Skeletal Maturity of Youths12-17 Years · 2016. 1. 26. · Skeletal age (hand-wrist) and...

Data from theNATIONAL HEALTH SURVEY

Skeletal Maturity ofYouths 12-17 YearsRacial,GeographicArea, andSocioeconomicDifferentialsUnitedStates,1966-1970

Skeletal age (hand-wrist) and bone-specific skeletal ages (asassessed by the Health Examination Survey Standard, based pri-marily on the Greulich-Pyle Radiographic Atlas) of boys and girlsage 12-17 years, by chronological age, race, geographic region,population size or land use of area of residence, annual familyincome, and education of parent.

DHEW Publication No. (PHS) 79-1654

Series 11Number 167

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFAREPublic Health Service

National Center for Health StatisticsHyattsville, Md. October 1978

/“

,

Library of Congress Cataloging in Publication Data

Roche, Alex F.Skeletal maturity of youths 12-17 years.

(Vital and health statistics: Series 11, Data from the National Health Survey, Data fromthe health examination survey; no. 167) (DHEW publication; no, (PHS) 79-1 654)

Includes bibliographical references.1. Skeletal maturity-United States. 2. Children in the United States–Anthropometry.

3. Health surveys-United States. I. Roberts, Jean, joint author. II. Hamill, Peter V. V.,joint author. III. Title. IV. Series: United States. National Center for Health Statistics. Vitaland health statistics: Series 11, Data from the National Health Survey, Data from the healthexamination survey; no. 167. V. Series: United States. Dept. of Health, Education, and Wel-fare. DHEW publication; no. (PHS) 79-1654. [DNLM: 1. Age determination by skeleton–In adolescence. 2. Bone development–In adolescence. 3. Racial stocks. 4. Socioeconomicfactors. W2 A N148vk no. 167.RA407.3.A347 no. 167 [GN63]ISBN 0-8406 -0121-2

312’. Q973s [573’.6’71097378-502

NATIONAL CENTER FOR HEALTH STATISTICS

DOROTHY P. RICE, Director

RO’BERT A. ISRAEL, Depu ty DirectorJACOB J. FELDMAN, Ph.D., Associute Director for Analysis

GAIL F. FISHER, Ph. D., Associate Director for the Cooperative Health Statistics SystemELIJAH L, WHITE, Associate Director for Data Systems

JAMES T. BAIRD, JR., Ph.D., Associate Director for International StatisticsROBERT C. HUBER, Associate Director for Afunagenrent

MONROE G. SIRKEN, Ph. D., Associate Director for Mathematical StatisticsPETER L. HURLEY, Associate Directorfor Operations

JAMES M. ROBEY, Ph. D., .4ssociate Director for Program DevelopmentPAUL E, LEAVERTON, Ph. D., Associate Directorfor Research

ALICE HAYWOOD, Information Officer

DIVISION OF HEALTH EXAMINATION STATISTICS

MICHAEL A. W. HATTWICK, M.D., Director

JEAN ROBERTS, Chiej h4edical Statistics Branch

ROBERT S. MURPHY, Clziej Survey F’larming and Development Branch

DIVISION OF OPERATIONS

HENRY MILLER, Chief, Health Examination Fie~ Operations Branch

COOPERATION OF THE BUREAU OF THE CENSUS

In accordance with specifications established by the National Health Survey, the Bureau ofthe Census, under a contractual agreement, participated in the design and selection of the sam-ple, and carried out the first stage of the field interviewing and certain parts of the statisticalprocessing.

Vital and Health Statistics-Series 11-No. 167

DHEW Publication No. (PHS) 79-1654Library of Congress Catalog Card Number 78-502

CONTENTS

Introduction .. ... .. ... .. ... .. ... .. ... .. ... ... .. ... .. ... ... .. .. ... .. .... .. ... .. ... .. .. ... . .... .. ... .. ... ... .. .. ... .. .. ... ... . .. ... .. .......................

Examination Method .. .. ... ... ... .. ... .. ... .. .... .. .. .. ... ... ... .. .. .... .. ... . ... ... .. ... ... .. ... .. ... .. ... .. ... .. .. ... .. .... .. . .. .. .. ... ... .. .. .....Field Radlo~aphy .. .... .. ... ... .. .. .. ... .. .... .. .. .. .... .. ... ... .. .. ... ... .. ... .. ... ... . .. .... . ... ... .. .. .... . .... . ... ... ... .. ... .. .... ..........Training of Assessors .. .. ... .. ... .. ... .. .. .... .. ... .. .... .. .. .. ..... .... .. .. .. . ... .. .. ... .. .. . .. ... .. .... . .. ... .. .... .. ... .. ... .. ... ... ... . ......Assessment Procedure .. .. .. ... ... .. ... .. ... ... .. ... . .. .. .. .. . .. ... .. .... . ... ... ... . ... ... ... .. .. ... ... .. .. ... ... ... .. ... .. ... .. .. ... .... .. .. ....

Skeletal Age (Hand-Wrist) Findings .. .. .. .. .. .. .. .. .... .. .. ... ... .. .... . .. ... ... ... .. ... . .... .. ... .. .. .. ... ... ... .. ... .. ... .... . ... ... .. .. ... ..Race ... .... . ... ... ... ... . ... ... .. .. .. . ... ... .. .. ... .. ... ... .. .... .. .. ... ... . ... ... .. ... .. .... .... .. ... .. ... .. ... .. .. .... .. ...............................Geographic Re@on ... .. .. ... .. .... .. .. ... ... .. .. ... .. ... .. ... ... ... .. ... .. ... .. .... . .. ... .. ... .. .... .... .. .... .. . .. . .... .. .. ... ... .. .. ... ........Urbm.Rurd . ... .. ... ... ... ... . ... ... .. ... .. ... .. ... .. ... ... ... .. .. ... .. .. ... .. .... .. ... .. ... .. ... .. . .. .. .. ... ... .. .. ... .. ... .. .... ...................Family Income .. .. ... .. .... .. ... .. .... .. .. ... ... ... .. .. .... . .... . ... .. .... .. ... .. ... .. .. ... .. .. ... ... .. .. ... ... .. ... .. ... ... ... .. .. ................Parental Education . .. .. .. .. . ... .. ... .. ... ... .. .... . .... ... . ... .... . ... .. .. .... .. ... . .... .. ... . ..... . .. ... .. ... .. ... .. ... .. .... .. .. ... ... .........

Bone-Specific Skeletal Age Findings .. .. ... .. ... .... .. ... . .. ... .. .. .. ... ... .. ... .. .... .... .. .. .. . .. ... .. ... .. ... . .... .. ... .. ... ... . .... . .... ..Race .. .... . .. .. .. .. ... .. ... ... ... .. ... ... ... . .... .. ... .. ... ... ... .. ... .. ... .. ... .. ... ... ... .. . ... .. .... .. ... . ... ... .. .. ... .. ... ................ ..........Geographic ReQon .... . ... ... .. ... .. .. ... ... .. .. ... .... ... .. .. .. ... .. .... .. .. .. . ... .. .. ... . .. .. .. .. .. . ... .. ... .. .. ... .. . .. ... .. ... .. ... .. ........Family Income .... .. .. .. ... ... .. ... .. .. ... .. .... . .... ... .. .. ... .. ... ... . .. . ... ... .. .. ... .. ... .. .. .... .. ... . .... .. ... .. ... .. ... . ... .. . ..............Range of Bone.Specific Skeletal Ages .. .... .. .. .. . ... .. ... ... .. .. .... .. .. ... .. ... ... .. ... .. .. ... . ... ... .. ... .. ... ... ... .. .. ... ... .. .. ...

Onset of Ossification Findings . .. .... . .. ... .. ... .... .. .. .. ... ... . .... .. ... ... .. .. ... ... ... ... . ... .. .. ... ... .. .. ... .. ... ... ... . .... .. .. ... ... ... . .Race . .. .. .. ... ... . .. .. .. ... .. .... ... .. .. ... .. ... .. .. .... ... . .. .... .. ... .. .. . .. .... . ... ... .. .. ... ... .. ... .. .. ... .. .... . ... ................................Geographic ReQon .. ... ... .. .. ... .. ... .. .... .. . .. .. .. ... .. ... ... .. ... ... . .... .. .. ... .. .. ... .. ... ... .. ... .. .. ... ... .. ... .. .... . ... ... .. .. .........Family Income ... ... ... ... . .. .. .. .... .. ... .. .... . ... .. .. .. . .. .... ... .. .. . .. .. .. ... ... .. .. .. .... .. ... .. . ... ... ... ... . ... ... .. .... . ... ...............

Epiphyseal Fusion Findings ... .. ... .. ... .. .... .. . .. . .... .. ... .. ... ... . ... ... ... . ... .. ... ... ... .. . .. . ... .. .. .. . ... ... .. ... .. ... ... .. .. ... .. ... .. ...Previous Studies . ... .. .. .. .. .. ... ... ... ... .. .. ... .. .... .. .. ... .. ... .. .. .... .. .. .. ... .. .. .. ... ... .. ... . .... .. ... .. .... .. . .. . ... ... .. .. ...............

Discussion .. .... . ... ... ... ... .. ... .. ... .. .... .. . .. .. ... .. .. ... .. ... .... .. .. .. . .. ... . ..... . ... .. .. .. .. ... .. .... . ... .. ... ... .. .. .. ............................Race . ... ... .. ... .. ... ... .. ... ... ... .. .. ... .. .... .. ... .. ... .. .. .... .. ... .. ... . .... .. ... .. ... .. ... .. ... .. .. ... .. ... .. .. .. .... ..............................Geographic Re~on .... ... ... .. .. . .. ... . .... ... .. .. ... ... .. ... .. ... .. .... . ... ... ... . ... .. .. ... .. .. ... ... .. .. .. ... .. .... .. .. ... ... .. ... ... .........Urban. Rural .. ... .. ... .. .... .. .. ... ... ... ... .. .. ... ... .. ... .. .... .. ... .. . ... ... ... . .... .. .. ... .. ... . ... ... ... .. ... . .... .. ... ... .. .....................Socioeconomic Factors ... .. ... ... ... .. .. ... .. ... ... ... .. ... ... ... . ... ... ... . ... .. .. ... . .... .. ... . ... ... .. .. ... ... .. ... .. ... ... ... . ... .. ... .. . ..nlness .. .. ... ... .. ... ... .. .. .. .. .. ... ... ... .. ... .. .. .... . ... .. .. .. .. .. .. .... . .... . .... .. ... .. ... .. .. ... ... .. .. .. ... .. ... .. .. .............................Diet ... .. .. ... ... .. .. .... .. .. ... .. ... ... .. ... ... ... . .. .. .. .. . ... .. .. .... .. .. ... ... .. .. .. ... ... .. ... . .... .. ... . .... .. .. .. ... ...............................

Summmy ... ... .. ... ... .. .... .. .. ... ... .. .. .... .. .. .. .... .. ... .. .... .. ... .. ... .. ... .. ... .. .... . ... ... .... .. ... .. .. ... .. ... .. ... .............................

References . .. .. ... .. ... ... ... ... .. ... ... .. .. ... ... ... .. .. .... .. ... .. ... ... .. . ..... . ... ... . .. . .. ... ... ... .. ... .. .. .. .. .. . .. ... .. ............................

Lkt of Detailed Tables ... ... ... .. ... ... .. .. ... ... .. .. ... ... .. .... . .. ... .. ... .. .... . ... ... .. .. .... .. .. .. ... .. .. ... ... ... . ... .. .... .. ... . .... . .........

AppendixesL Statistical Notes . .... . ... ... .. .. ... ... ... .. ... .. .. .... ... . .. .... .. .. ... .. .. ... ... . .. .. . .. . ... .. ... ... .. .. ... ... .. .. .. ... .... .. .. ... .. ........11, Demo~aphic and Socioeconomic Terns . ... .. .... . ... ... .... . .... .. .. ... .. .. ... ... . .... .. .. ... ... ... . .... .. .. .. .... .. . .... . ...III. Reliability of Assessments ... .. ... .. .. .. . .... .. ... .. .. .... . ... .. .... .. .. .. .... .. .. .. ... ... .. .. .. .. .. . ... .. .. ... ... .. .... . .... . .. ... ... .

LIST OF FIGURES

1. Mean difference inmonths between skeletal age (hand-wrist) and chronological age forwhite andNegro boys and white and Negro girls age 6-17 years by chronological age in years: United States,

1963.1970 ... .. .. ... ... .. .... . ... ... .. ... .. ... ... ... ... .. . ..... . ... .. .... .. ... . ... ... .. .. .. .. . .. .. . . .. ... .. .. ... .. .. ... .. .... .. .. ................

1

3334

56

19212225

2526272727

29292929

3232

33343738384041

42

45

52

909597

6

.Ill

2. Mean difference inmonths between skeletal age(hmd-tist) andchronolo#cd age forwhite boysand girls and Negro boys and girls age 6-17 years by chronological age in years: United States,1963.1970 .......................................................................................................................................

3. Difference between actual andexpected mean skeletal age (hand-wrist) forwhite and Negro boysand girls 6-17 years of chronological age: United States, 1963-1970 ...............................................

4. Relative variability in skeletaf age (hand-wrist) among white and Negro boys and girls age 6-17years by chronological age in years: United States, 1963.1970 .......................................................

5. Differences between skeletal and chronological a es of boys 12-17 years in studies of Flory1%(1936),16 Simmons (1944), 17 and Todd (1937) ........................................................................

6. Differences between skeletrd and chronological ages of boys 12-17 years in studies of Fry(1966), 21 Maresh (1970), 22 Johnston (1962),19 Greulich and Pyle (1959),10 and U.S. youths(1966-1970) ...................................................................................... ........................................... ...

7. Differences between skeletaf and chronological a es of ~rls 12-17 years in studies of Flory(1936), 16 Simmons (1944), 17 and Todd (1937)1 #........................................................................

8. Differences between skeletal and chronological ages of girls 12-17 years in studies of Fry (1966),21Maresh (1970),22 Johnston (1962),19 Greulich and Pyle (1959),10 and U.S. youths (1966-

9. Mean difference in months between skeletaf age (hand-wrist) and chronological age for boys andgirls age 6-17 years by region and chronological age in years: United States, 1963-1970 ............... ..

10. Difference between actual and expected mean skeletaf age (hand-wrist) for boys and girls 6-17years of chronological age by region: United States, 1963.1970 .....................................................

11. Difference between actual and expected mean skeletal age (hand-wrist) for white and Negro boysand girls 6-17 years of chronological age by region: United States, 1963-1970 ...............................

12. Mean difference in months between skeletal age (hand-wrist) and chronological age for boys andgirls age 6-17 years by ammaf family income and chronological age in years: United States, 1963-1970 ................................................................. .............................................................................. .

13. Difference between acturd and expected mean skeletal age (hand-wrist) for boys and girls 6-17years of chronological age by annual income: United States, 196$-1970 ........................................

14. Difference between actual and expected mean skeletal age (hand-wrist) for white and Negro boysand girls 6-17 years of chronqlogicaf age by annual family income: United States, 1963 -1970 .......

LIST OF TEXT TABLES

A. Minimum and maximum acceptable skeletal ages in months using the HES male standards: HealthExamination Survey, 1966.1970 .....................................................................................................

B. Mean differences in skeletal age (years) between Greulich-Pyle and Tanner-Whitehouse assessments(GP - TW) of the same radiographs .................................................................................................

c. Modaf differences between skeletal age and chronological age (S.A. - C.A. in years) in some Negro

7

10

11

11

11

12

12

20

21

22

23

24

25

4

4

youths in other counties ................................................................................................................ 16

D. Modsd Greulich-Pyle skeletal age levels (S.A. - C.A. in years) in southern Chinese youths ................. 16

E. Modal skeletal age levels (S.A. - C.A. in years) of American youths of Japanese ancestry40 andJapanese youths in Japan42’43 ....................................................................................................... 17

F. Standard deviations (years) of skeletaf age for U.S. youtiS, ............................................................... 18

G. Standard deviations (years) of skeletaf age in groups of youths outside the United States ................. 19

H. Modaf ages (years) for onset of ossification in selected bones in U.S. white youths ... ........................ 30

J. Modal ages (years) for onset of ossification in youths of European ancestry living in Europe ............ 31

K. Modal ages for epiphyseal fusion in the hand-tist of U.S. white youths ........................................... 32

L. Reported ages of epiphyserd fusion in Japanese youths ...................................................................... 33

M. Correlation coefficients between skeletal age (Greulich-Pyle) and year of birth in the Fels Longi-tudinal Study (Roche, unpublished data) ........................................................................................ 35

N. Mean relative differences between parent-offspring pairs in skeletal age (RWT, knee in years) ........... 36

0. Mean skeletrd ages for southern Chinese youths in Hong Kong at various socioeconomic levels(Low et al., 1964)39 ....................................................................................................................... 38

P. Retardation (years) in age of onset of ossification of hand-wrist centers in malnourished whiteyouths (data of Dreizen et al., 1958)169 ......................................................................................... 41

v

SYMBOLS

Data not available-----–---–--------–--–—-- ---

Category not applicable--------------—---——-- . . .

Quantity zero---------—---------—---—- -

Quantity more than Obut less than 0.05—- 0.0

Figure does not meet standards ofreliability or precision---------—----—- *

vi

SKELETAL MATURITY

OF YOUTHS 12-17 YEARS: RACIAL, GEOGRAPHIC AREA,

AND SOCIOECONOMIC DIFFERENTIALS

Alex F. Roche, M.D., Fels Research Institute;Jean Roberts and Peter V. V. Hamill, M.D.,

Division of Health Examination Statistics

INTRODUCTION

This report presents national estimates ofthe levels of hand-wrist skeletal maturity amongnoninstitutionalized youths age 12-17 years inthe United States, by race, geographic area ofresidence, and socioeconomic background, basedon findings from the Health Examination Surveyof 1966-1970. The previous report on these radi-ographic findings among youths,l which waslimited to the sex differences in skeletal matu-rity in relation to chronological age, contains amore comprehensive description of the nature ofskeletal maturation among youths and of theassessment method used in the survey.

Both the findings in these two reports onskeletal maturity among youths age 12-17 yearsand those from the corresponding reports amongchildren age 6-11 yearsz $3 are the first nationalestimates of skeletal maturity levels made forthese age groups in this or any other country.These studies provide estimates of known relia-bility against which present assessments of chil-dren and youths can be compared and possiblefuture changes in skeletal maturation rates, forthe country as a whole, can be judged.

The Health Examination Survey (HES) isone of the major programs of the National Cen-ter for Health Statistics (NCHS), authorizedunder the National Health Survey Act of 1956by the 84th Congress as a continuing Public

Health Service function in determining thehealth status of the U.S. population.

Four types of survey programs are used tocarry out the intent of the National Health Sur-vey.4 The Health Interview Survey collectsinformation from samples of people by house-hold interview and focuses primarily on theimpact of illness and disability within variouspopulation groups. The programs in the Divi-sions of Health Resources Utilization Statisticsand Health Manpower and Facilities Statisticsobtain health data as well as health resource andutilization information through surveys of hospi-tals, nursing homes, and other resident institu-tions and the entire range of personnel in thehealth occupations. The Health ExaminationSurvey, from which data in this report wereobtained, collects health data by direct physicalexaminations, tests, and measurements per-formed on samples of the population. The latterprogram provides the best way of obtainingactual dia~ostic data on the prevalence of cer-tain medically defined illnesses in the generalpopulation. It is the only effective way to secureinformation on unrecognized and undiagnosedconditions and on many physical, physiological,and psychological measures within the popula-tion, Also it collects demographic and socioeco-nomic data from the sample population understudy to which the examination findings may berelated.

The Health Examination Survey is organizedas a series of separate programs or cycles each ofwhich is limited to some specific segment of theU.S. population and to specific aspects ofhealth. From data collected during the firstcycle, the prevalence of certain chronic diseasesand the distribution of various physical andphysiological measures were determined on across-section of the defined adult population aspreviously described.s ~6

For the second examination survey program,a probability sample representative of the nonin-stitutionalized children age 6-11 years in theUnited States was selected and examined in1963-1965. The examination in this cross-sec-tional study primarily assessed health factorsrelated to growth and development, as describedin a previous report.7

The third cycle, on which findings in thisreport are based, was similar in design and pur-pose to the preceding children’s program. Forthis third survey, a probability sample represent-ative of the noninstitutionalized youths age12-17 years in the United States was selected forexamination. The examination in this cross-sec-tional study primarily assessed health factorsrelated to growth and development, usingmethods similar to those in the preceding chil-dren’s study supplemented as previously de-scribed for this older age group.1 YS

Included were examinations given by apediatrician, assisted by a nurse, an examinationby a dentist, tests administered by a psycholo-gist, and a variety of tests and measurements bylaboratory X-ray technicians.

Field collection operations for this youths’cycle, which started in March 1966, were com-pleted in March 1970. Of the 7,514 youthsselected in the sample, 6,768 youths, or 90 per-cent, were examined. The response rate washigher among Negro youths (96.6 percent) thanamong white youths (89. 1 percent) and loweramong white girls, particularly at 17 years ofchronological age, than among white boys,Negro boys, or Negro girls. The extent to whichthese differential response rates will affect theprecision of the national estimate for white andNegro youths is discussed in greater detail inappendix I. This national sample is representa-tive, and the examined group closely representa-tive, of the 22.7 million noninstitutionalized

youths age 12-17 years in the United States withrespect to age, sex, race, geographic region, pop-ulation size of place of residence, and rate ofchange in population size of place of residencefrom 1950 to 1960. The sample design for theyouths’ survey used the same sampling areas andhousing units as the preceding survey amongchildren. As a result, nearly one-third of theyouths in the present study had also been ex-amined in the children’s survey.

The examinations were conducted consecu-tively in 40 different locations throughout theUnited States. During the single visit, each youthwas given a standardized examination by theteam in the mobile units specially designed foruse in the survey. Prior to this examination,demographic and socioeconomic data on house-hold members as well as medical history, behav-ioral, and related data on the youths to beexamined were obtained from their parents.Ancillary data were requested from the schoolsattended by the youths, including their gradeplacement, school behavior, adjustment, ~dhealth problems known to their teachers. Anadditional Health Habits and History form wascompIeted by the youth before he or she arrivedfor the examination, and a Health Behavior formwas completed by the examinee while in the

examining center. Birth certificates of theyouths were obtained for verification of age andfor information related to their condition atbirth.

The same methods and measure of skeletalmaturation were used in the examination sur-veys among children and youths. In planning forboth survey programs, the advice of cliniciansand directors of long-term studies of skeletaldevelopment had been obtained about possibleuses of skeletal maturity levels and methods ofassessing skeletal age from radiographs. Thedirectors of growth studies conducted independ-ently from 1929 to 1962 at the Brush Founda-tion in Cleveland, Ohio, and the Department ofMaternal and Child Health at Harvard Universityin Boston, Massachusetts—Drs. William WalterGreulich and Harold C. Stuart–recommendedthat Dr. S. Idell Pyle prepare a single standardfrom their radiographic series specifically for usein the Health Examination Survey. The 1964Manual-the preliminary edition of A Radio-graphic Standard of Reference for the Growing

2

Hand and Wristg–was prepared for this purposeby Drs. Pyle and Greulich. This will be referredto in this report as the “HES Standard.”

The general concept of skeletal maturity, themethodology by which radiographs were takenand later assessed, and the quality control meas-ures used have been described in detail and dis-cussed in the first reports on skeletal maturity ofchildren 6-11 yearsz and youths 12-17 years.1

A brief description of the sample design,quality control methods, and reliability of thedata, as well as the population and samplingerror estimation procedures used in reportingthe findings of this study, is contained in appen-dix L Definitions of the demographic terms usedin this report are included in appendix II, and anevaluation of the reliability of the assessments isshown in appendix III.

EXAMINATION METHOD

At each of the preselected locations through-out the United States used in this study, theyouths were brought to the centrally locatedmobile examination center for a standardizedexamination which lasted about 3-1/2 hours. Sixyouths were examined in the morning and six inthe afternoon. When each youth entered theexamination center, an oral temperature wastaken and a screening for acute illness was made.If such illness was detected, the youth was senthome and reexamined later. All six proceeded todesignated but different stations for the start ofthe examination after changing into gymna-sium-type shorts, cotton sweat socks, a robe and(for girls only) a light sleeveless topper. Thesequence of elements in the examination dif-fered for each youth so that all six could beexamined simultaneously during the half day.The time of each part of the examination wasrecorded, but there is no reason to believe thattime of day or sequence of examination wouldaffect the composition or quality of the radio-graphic data.

Field Radiography

Each vouth was scheduled to have a 10” x12“ radiograph of thewhich the positioning

right hand and wrist forwas in accordance with

specifications in the Greulich-Pyle Atlas. 10Although some radiographs were made usingother film sizes when the 10“ x 12“ size wasscarce, this would not have influenced the find-ings in the assessment method used. Technicallyinadequate films could be repeated because theywere developed immediately in the field. Henceeach youth’s record contained a single radio-graph showing the dorso-palmar view of his orher entire hand-wrist with its full complement ofossifying parts at the time of the examination.

As indicated previously, the decision to radi-ograph the right hand-wrist rather than the left,which is the more frequent anthropometric prac-tice, was made on the advice of anthropologistconsultants who were interested also in the useof related measurement data for equipmentdesign in which right-side measurements werepreferred. When the selected radiographs used inthe plates from the Greulich-Pyle Atlas andthose from other sources were reproduced in theHES Standard, they were reversed photograph-ically so they could be used in right-side assess-ments. Previous reports on lateral differences inskeletal maturity of the hand-wrist, either forthe area as a whole or bone by bone, have shownthat these are too small to be of practical impor-tance.1 1

Training of Assessors

The assessments ofhand-wrist radiographs

skeletal age from theof youths age 12-17

years in the H&dth Examination Survey of1966-1970 were made by nine medical studentsat Case Western Reserve University. Theseincluded five of the medical students who haddone the assessments in the 1963-1965 nationalsurvey among children age 6-11 years. This workwas administered under a contract, with Dr. C.Wesley Dupertuis as project director, for theNational Center for Health Statistics. Under thedirect supervision of Dr. Pyle, training of theassessors and the implementation of relatedquality control procedures were done in themeticulous manner described previously. 1 Whenthe ratings and reliability for the new assessorreached good agreement with those of Dr. Pyle—the majority of differences within 4 months–that new assessor started his assessment of thesurvey radiographs. Reported evidence from

3

another studyl Z suggests that at the end of thistraining procedure the interobserver and intraob-server differences in skeletal maturity ratingswould be similar to those for experienced asses-sors.

Assessment Procedure

As previously described,l *Z the radiographswere assessed by comparison with prints of theseries of standards for the male hand-wristselected from those in the 1959 Greulich-PyleAtlasl 0 and other sources which have beenreversed so they appear to be of the right hand-wrist as shown in the 1971 Radiographic Stand-ard of Reference of Pyle et al.g The male skele-tal age equivalent values shown in that standardwere those used for the assessment of radio-graphs in both the national surveys among chil-dren and youths, with some very slight modifica-tion to smooth the skeletal age trend for a fewof the bones.

In making the assessments, the readers didnot have access to the chronological age, the sex,or other information about the youth. Eachbone on the radiograph of the hand-wrist wasrated separately and interpolation was madebetween standards to monthly intervals whenappropriate.

As a quality control measure and to permitdetermination of the leveI of reliability of theassessments throughout this study, independentreplicates were obtained on approximately 1 outof each 11 films. One randomly selected radio-graph in each 23 was rated independently byanother assessor for a measure of interobservervariability, and one randomly selected radio-graph among each 20 was rated independently asecond time by the same reader to give a meas-ure of intraobserver variability. For the latterset, the time lapse between the first assessmentand the reassessment was sufficiently long thatthere was little likelihood of recall. There wasalso no indication to the assessor that he wasmaking a reassessment. Information on thedegree of reliability of these assessments is givenin appendix III.

The order in which the bones were assessedwithin each radiograph was as listed in table A.This table also contains the minimum and maxi-mum bone-specific skeletal ages allowed in the

Table A. Minimum end maximum acceptable skelatal ages inmonths using the HES male standards: Health ExaminationSuwey, 1966-1970

Hand-wrist bone

Radius .... .. .. .. .. .. .. .. .. ... .. ... ... ... .. .... . ... .Ulna .. .. ... .. ... ... ... .. .. .. ... .. .. ... .... .. .. ... ...

Cavitate .. ... ... .. ... ... .. .. .. .. . ... .. .... .. .. .. ...Hamate .. .. .. .... ... .. .. ... .. .. .. .... ... .. .. ... .. ..Triquetral .... .. ... .. ... .. .. .... .. .. .... .. ... . ... .

Lunate ... ... ... . .... . ... ... .. .. .. .... ... .. ... ... . ..Scaphoid .. .. .. . ... .. ... . .... .. ... .. ... ... ... .. ...Trapezium .... ... .. .. .. .... .. .. .... .. .. .. .... .. ..Trapezoid .... .. . ... .... . ... .. .... .. .. ... ... .. . ...

Metacarpal I ... .. .. ... .. ... .. .... .. .. .. ... .... ..

Metacarpal II .. ... .. .. .. .... .. ... . .... .. .... .. ..

Metacarpal Ill ... .. ... ... .. ... . ... ... .. ... ... ...Metacarpal IV .... ... .. . ... .. .. . .. ... ... ... .. .. .Metacarpal V .... .. . ... .. .. .. .... .. ... .. ... ... ..

Proximal phalanx 1... .. ... .. .. .. ... ... .. ... .

Proximal phalanx I I-V ... .. ... .. .. .. ... ... .Middle phalanx I I-I V ... .. ... .. .... .. .. .. ...Middle phalanx V .... .. .. .. .... .. .. ... . .... ..

Distal phalanx 1.. ... .. .. .. ... .. .. ... ... .. ... ..

Distal phalanx 11, V .... .. .. ... ... .. ... ... . ..Distal phalanx Ill .. .. ... ... ... . ... .. ... ... . ..Distal phalanx IV ... ... .. .. ... .. ... .. ... . ....

Pisiform ... .... .. . .... . ... . .... .. ... . ... ... .. .. .. ..Adductor sesamoid . ... .. .. ... .. ... . ... .. ....Flexor sesamoid .. .. .. ... .. .. .. .. ... ... ... ... .

~Skeletal age in months

1570

. . .

. . .

17

35

685168

25

17

161724

33152339

15392232

110

146158

228215

197197197

197197197197

191

215209209215

215209209

209

191191191191

197

197197

lMinim”m age (according to standard) of radio-oPacity of

epiphysis or carpal.2one month below “adult” age.

male standard values for this study and in thepreceding one among children. The lower limitfor the bone-specific skeletal age was arbitrarilyset midway between the last standard in whichthe particular bone was not radio-opaque andthe first in which it was radio-opaque. Excep-tions were made for the three later-ossifyingbones: the pisiform and the adductor and flexorsesamoids. For these bones the minimum valuesallowed were 2 months above the last standardin which the bones were not radio-opaque.

At the upper end of the range when epiphy-seal fusion or maturation was complete for aparticular bone, only the designation “adult”and not a skeletal age in months could beassigned. The median ages in months, from theHES Standard, at which this occurs in boys wereused as the bone-specific skeletal age beyond

4

which only this designation “adult” could beapplied. The maximum allowable values 1month below this “adult” skeletal age are shownin table A.

As expected within chronological age inter-vals, the skeletal ages assigned to the girls weremore advanced than those assigned to the boys.This occurs because, although boys and girls passthrough essentially the same skeletal maturitystages, girls tend to mature more rapidly thanboys. Bone-specific female equivalent skeletalages were determined during the preparation of

the HES Standard but were not used in theass cssment of the survey radiographs. Themethod by which these female equivalent skele-tal age values were obtained is described in detailin Pyle et al.g In summary, these ages were esti-mated using three sets of serial radiographs ofnormal U.S. girls. The modal radiograph (inmaturity) for each chronological age group ineach set was assessed against the female stand-ards in the Greulich-Pyle Atlasl 0 and against theHIM Standard (male). Later these sequentialfemale equivalent skeletal ages were smoothed.

The skeletal age data for girls in the detailedtables of this report are given both in terms ofthe male standards, as originally assessed, and interms of the female equivalent skeletal ages thatwere obtained by converting the data recordedoriginally. The skeletal age values for the wholehand-wrist for boys and girls in this report weredetermined by computer from the originalbone-specific assessments by averaging the agesassigned the hand-wrist bones for each youth.

SKELETAL AGE(HAND-WRIST) FINDINGS

The preceding report on the skeletal matura-tion of youths age 12-17 years in the UnitedStatesl describes and analyzes the trend andextent of variation in the timing and velocity ofthis aspect of osseous development by age andSCX, without regard to racial or socioeconomicclassification. It includes a further analysis ofthese trends across the entire age range 6-17years for boys and girls in the United States, aswell as comparisons with findings from the pre-vious more geographically limited studies in thisand other countries. The national estimates of

skeletal maturity among U.S. children andyouths are based on findings from the HealthExamination Surveys of 1963-1965 and1966-1970 in which hand-wrist radiographsobtained for the national probability y samples ofexaminees were assessed against the HES Stand-ard for the hand-wrist using the Greulich-Pylemethod, as previously described.

In brief, among youths 12-17 years of age,the mean skeletal age (hand-wrist) of boys in theUnited States has been shown to increase consist-ently with chronological age from 11.7 years(140.2 months) for those 12 years of age at theirlast birthday (mean chronological age 12.5 yearsor 150 months) to 17.1 years (205.4 months) atchronological age 17 years (mean chronologicalage 17.5 years or 210 months). The yearly incre-ment in skeletal age is at a maximum amongboys age 12-14 years and then decreases at ages16 and 17 years to the same levels found amongboys age 6-11 years. When assessed against them~e s&ndard,- the mean skeletal age (hand-wrist) of girls in the United States increases from14.6 years (174.9 months) at chronological age12 years to 17.6 years (211.3 and 211.5months) at ages 16 and 17 years. During the6-year time span the yearly increment in skeletalage for girls is consistently less than that forboys of comparable chronological age and stead-ily decreases from a maximum at ages 12 and 13years across the remainder of the age range asproportionately more of the girls had reachedthe point at which epiphyseal fusion in theirhand-wrists is completed–the upper limit ofskeletal maturation.

On transformation to female equivalentvalues, which compensate for the more rapidskeletal development of girls compared withboys, the mean skeletal age (hand-wrist) of girlsin the United States increases with chronologicalage from 11.9 years (142.9 months) at age 12years to 15.5 years (185.6 and 186.0 months) atchronological ages 16 and 17 years, respectively.

The mean lag of skeletal age (hand-wrist)behind chronological age for boys drops from apeak of 13.8 months at age 11 years (from the1963-1965 national survey) to 9.8 months at age12 years and continues to decrease to less than 1month at 14 and 15 years before increasingagain to nearly 5 months at age 17 years. Amonggirls, the lag of skeletal age (female equivalent

5

values) behind chronological age at 12 years (7.1months) is slightly less than the maximum valueof 9.8 months at age 11 years (from the1963-1965 national survey) and decreasesslightly to a minimum of 6.0 months at age 14years. For girls from age 15 years on, the lag ofskeletal age behind chronological age becomes

progressively greater, reaching a maximum of 24months at age 17 years. The reasons for thesesomewhat inconsistent patterns among olderyouths have been discussed in detail in a pre-vious report. 1

Race

White.–The mean skeletal age (hand-wrist)of white boys in the United States increases withchronological age from 11.7 years (140.4months) for those 12 years of age at their lastbirthday (mean chronological age 12.5 years or150 months) to nearly 17.2 years (205.8

months) at chronological age 17 years (meanchronological age 17.5 years or 210 months) asshown in table 1. Among these white boys, theyearly increment in mean skeletal age is at amaximum of 16.9 months between chrono-logical ages 13 and 14 years and then decreasesto 8.8 months between ages 16 and 17 years.

The mean lag of skeletal age (hand-wrist)behind chronological age for U.S. white boysdrops from 9.6 months it age 12 years to 0.3months at age 14 years. The mean skeletal ageexceeds the chronological age by 1.1 months at

age 15 but again lags 1.0 month behind thechronological age at age 16 and lags by 4-.2months at age 17 years (figures 1 and 2).

Across the entire age range 6-17 years, meanskeletal age of white boys increases consistentlywith chronological age from 6.2 years (74.9months) at age 6 years to nearly 17.2 years(205.8 months) at age 17 years (table 1 andreference 3). The yearly increment is maximal

+5

r

BOYS

gwK -20uu.~0

zwz -25

I I I 1 I I I I I I I I 1

6 B 10 12 14 16 18

CHRONOLOGICAL AGE IN YEARS AT LAST BIRTHOAY

+5

r

GIRLS

(female equlvdem]

o

-5 —

-lo —

-15 —

-20 —

-25 —

\ \ .

Negro

1 I I I I I I I I I I I I I

6 8 10 12 14 16 16


Figure 1. Mean difference in months between skeletal age (hand-wrist) and chronological age for white and Negro boys and white andNegro girls age 6-17 years by chronological age in years: United States, 1963-1970

6

{5 ro

-5 -

-lo —

-16 —

-20 —

-2s —

WHITE

\II!IL1

11\1

Girls ~[female equivalent]

I I I [ I r I 1 1 I 1 I I

6 8 10 12 14 16 16

CHRONOLOGICAL AGE IN YEARS AT LAST 61RTHDAY

+5 —

o

-5 —

-lo —

-15 —

-20 —

-25 —

NEGRO

it

it1I

i

i,iII1

Ciirk ‘{female equivalent)

I 1 I I I 1 I 1 I I I I I 1

6 6 10 12 14 16 18

CHRONOLOGICAL AGE IN YEARS AT LAST 61RTHOAY

Figure 2. Mean difference in months batween skeletal age (hand-wrist) and chronological age for white boys and girls and Negro boys

and girls age 6-17 years by chronological age in years: United States, 1963-1970

(16.6, 16.4, and 16.9 months) from age 11 to 14years and minimal (8.0 months) between 9 and10 years of chronological age. The maximum lagof mean skeletal age behind chronological age isthe 14.2 months difference at age 11 years(from the 1963-1965 national survey).

As measured by the standard deviation, thevariability in skeletal maturity (hand-wrist)among white boys decreased with chronologicalage from maximum values of 17.17 months and17.77 months at ages 12 and 13 to 10.97months at age 17 years, The standard deviationis substantially greater among boys age 12-15years than among those younger (6-1 1 years) orolder (16 or 17 years). The relative variability(i.e., 100 times standard deviation divided bythe mean) among white boys decreases duringages 6-10 years (from 15.3 to 9.0), is slightlygreater again at ages 11-13 years (10.5, 12.2,11.3), and decreases steadily from age 14 yearsto 18 years (from 8.5 to 5.3).

Among white girls in the United States, themean skeletal age (hand-wrist ), assessed againstthe male standards, increases from 14.5 years(174.3 months) at age 12 years to 17.6 years(21 1.7 months) at age 17 years. Across theentire age span 6-17 years in the two nationalsurveys, the mean skeletal ages (male standard)for white girls increase from 7.5 years (89.7months) at age 6 to 17.6 years (21 1.7 months)at age 17. The yearly increment in mean skeletalage for white girls in the youth age range is at amaximum of 12.2 months between ages 12 and13 years and decreases to the minimum of 0.2month at age 17. In the earlier survey of chil-dren, the largest annual increment was 19.2months for the interval 10-11 years. The meanskeIetaI age (male standard) of white girls isabout 2 years in advance of their chronologicalages at 12, 13, and 14 years (24.3, 24.5, and23.9 months, respectively). This advancementdecreases to a minimum of 1.7months at 17

7

years. The means of the girls (male standard) areconsistently in advance of chronological age forthe entire 6-1 7-year range by values that aremaximal (about 24 months) at ages 12-14 yearsand minimal at age 17 years.

The variability of skeletal age (hand-wrist),as measured by the standard deviation, is greateramong younger white girls of 12 and 13 years(14 and 13 months) than among those 14-17years, where the st~dard deviatio~s are 9 to 10months. The variabilityy, relative to the mean,decreases from a maximum at age 12 and levelsoff from ages 15-17 years. The variability inskeletal age for white girls, when consideredacross the entire age span 6-17 years, is greatestat age 10 (s%= 17.28 months) and least from 14years on (9-10 months). When considered inrelation to the size of the mean, the relative vari-ability is greatest at age 6, somewhat higher at7-10 years, and then declines to minimum valuesat ages 15-17 years.

When conversion is made to the femaleequivalent values for white girls in the youth agerange, the mean skeletal ages increase from 11.9years (142.3 months) at 12 years to 15.5 years(186.0 months) at age 17. The yearly incrementin these mean values is slightly greater at ages 12and 13 years (12.5 and 13.1 months) than atother ages and later decreases to the minimum(0.2 month) at age 17.

The lag of mean skeletal age (hand-wrist)behind chronological ‘age, in terms of the femaleequivalent values, for white girls decreases veryslightly from 12 years (7.7-month lag) to 14years (6.1 months) then steadily increases to amaximum at age 17 (24.0 months).

From the two national studies, during theage span 6-17 years (reference 1-3 and table 1),the mean skeletal age (hand-wrist, female equiva-lent values) for white girls increases from 6.4years (76.7 months) at age 6 years to 15.5 years(186.0 months) at chronological age 17 years.The yearly increment in these values is maximal(14.2 months) between ages 11 and 12 years andnearIy as great between 13 and 14 years, thenfrom 14-16 years decreases to levels that do notdiffer significantly from those in the younger,6-1 1-year, age groups. The lag of skeletal age(hand-wrist, female equivalent values) behindchronological age for white girls, which increasesfrom 1.3 months at age 6 to 9.9 months at age

11, becomes slightly smaller at ages 12-14 (lagsof 7.7, 7.2, and 6.1 months) and then increasesto the maximum value of 24 months at age 17years (figures 1 and 2).

White girls consistently are more advanced inskeletal maturity than white boys across theentire 6-1 7-year age range when both areassessed against the single male standard. How-ever, when the female equivalent values for girlsare used in this comparison (figure 2), the meanvalues for younger white girls generally tend toexceed those for white boys up to age 12 years, ,although these mean differences are negligible atages 7-9 years. From 13 years on, the meanskeletal ages for white girls are significantlylower than those for white boys; these mean dif-ferences increase steadily with chronological agefrom 2.0 months at age 13 years to 19.8 monthsat age 17 years. This disparity is due, in part, tothe fact that there are progressively fewer girls inthe older age groups whose hand-wrist bones arestill maturing; hence these comparisons are madebetween the majority of boys and only the latermaturing girls, as discussed in a previous report.1

Negro.-Among Negro boys in the UnitedStates, the mean skeletal age (hand-wrist) valuesincrease steadiIy from 11.6 years (138.7months) at age 12 to 16.9 years (202.4 months)at age 17 years. Across the age range 6-17 yearsin the two national surveys (references 1-3 andtable 1), mean skeletal age (hand-wrist) forNegro boys increases from 6.6 years (79.0months) at age 6 years to 16.9 years (202.4months) at age 17 years. The yearly increment ismaximal (21.9 months) between ages 12 and 13years and minimal (9.0 months) between ages 14and 15 years. When considered over the entireage range of the two surveys combined, theyearly increment is maximal (21.9 months)between ages 12 and 13 years and minimalbetween 8 and 10 years (5.5 and 5.9 months).The mean lag of skeletal behind chronologicalage for Negro boys is greatest (11.3 months) atage 12, decreases to only 1 month at 13-14years, and then consistently increases to 7.6months at age 17.

Skeletal maturity (hand-wrist) of Negro boysis more variable at age 13 years (s% = 19,69months) and least variable at 17 years (standarddeviation of 11.37 months). The variability rela-tive to the mean for Negro boys shows a similar

pattern of change but decreases more consist-ently with chronological age from 13 to 17 yearsthan dots the standard deviation.

For the age span of the children’s andyouths’ surveys combined, variability, as deter-mined by the standard deviation, is greatest atage 13 and least at ages 8-10 years (10.11,10.58, and 10.27 months). However, relativevariability is greatest among the Negro boys 7and 6 years old and least among the oldest agegroup (17 years).

For Negro girls age 12-17 years, mean skele-tal agc (hand-wrist, male standard) increasesfrom 14.9 years (178.4 months) at chronologicalagc 12 years to 17.5 years (210.5 months) atchronological age 17 years. Across the 6-17-yeartigc span from the two national surveys, thernwm skeletal age (hand-wrist, male standard)for Negro girls increases consistently from 7.7years (91.9 months) at chronological age 6 yearsto 17.5 years (210.5 months) at age 17 years.The mean skeletal ages (hand-wrist, male stand-ard) for these Negro girls are consistently inadvance of their chronological ages across the6-1 7-year span by amounts that increase consist-cmtly from a minimum of 9 months among8-year-olds to values in excess of 24 months at12-14 years. Later this advancement decreases toIcss than 1 month at age 17 years.

The yearly increment for Negro girls is great-est at ages 12-15 years (9-11 months) and thendecreases to less than 1 month (0.3 month)between chronological ages 16 and 17 years. Themaximum yearly increase, for the total span6-17 years, is between ages 9 and 11 years (16.3and 16.1 months), and the minimum is amongthe oldest Negro girls (0.3 month between 16and 17 years).

The variability and the relative variability inskeletal age (hand-wrist, male standard) amongNegro girls is largest at age 12 and least at 15years in the survey of youths. When the datafrom both surveys are considered, the standarddeviation is greatest at ages 9-12 years (18.33,17.65, 17,28, 16.72 months) and least at ages 15and 16 years (8.35 and 9.36 months, respec-tivcly) for Negro girls.

On conversion to female equivalent values,the mean skeletal age (hand-wrist) of Negro girlsin the youth age range increases from 12.2 years(146.4 months) at age 12 to 15.4 years (184.5

months) at age 17 years. The yearly incrementin these mean values is largest between 13 and14 years (12.6 months) and later decreases toless than 1 month (0.3 month) between ages 16and 17 years. The lag of mean skeletal age(hand-wrist, female equivalent values) behindchronological age for Negro girls is 6 months orless from 12 to 15 years and later increases toexceed 25 months at age 17.

Across the age span 6-17 from the twonational surveys, the mean skeletal age (hand-wrist, female equivalent values) for Negro girlsincreases from 6.6 years (78.9 months) at age 6to 15.4 years (184.5 months) at age 17 years.The yearly increase is greatest between ages 11and 12 years (17.6 months) and slows to a negli-gible amount (0.3 month) between ages 16 and17 years. Only at age 6 years does the meanskeletal age exceed the chronological age forNegro girls, and then by less than 1 month.From 7 to 17 years, these female equivalentvalues lag behind chronological age. As seen infigure 2, the lag increases from 7 to 11 years,and decreases to less than 6 months at ages12-14 years, after which it increases to the maxi-mum of more than 25 months at age 17.

When both Negro girls and boys are assessedagainst the male standards, the girls are consist-ently more advanced in skeletal maturity thanthe boys are across the entire age range 6-17years. This is similar to the findings among whitechildren and youths. When comparison is madewith the female equivalent skeletal ages of girls,the mean skeletal ages for Negro boys consist-ently exceed those for Negro girls from age 13to 17 years, which is consistent with the findingsamong white youths. Only for the two oldestgroups (16 and 17 years) are the mean differ-ences large enough to exceed the 95-percentconfidence limit for the national estimates (sta-tistically significant at the 5-percent level).Among the younger age groups, 6-12 years, themean skeletal ages for Negro girls slightly exceedthose for Negro boys except at 6 and 8 years.

White-Negro. –White boys age 6-11 years are,on the average, generally slightly less matureskeletally than Negro boys. However, the pat-tern is reversed at age 12-17 years, when themean skeletal ages of white boys generally tendto exceed those for Negro boys in the UnitedStates (figures 1 and 3). Only at ages 10 and 13

9

Figure 3. Difference between actual and expected mean skeletalaae (hand-wrist) for white and Negro boys and girls 6-17y;ars of chronological age: United States, 1963-1970

years do exceptions to the above trends occur.By contrast, white girls are slightly but consist-ently less mature skeletally than Negro girls, 6through 15 years except at 8 years where themean values are identicaL Only among 16- and17-year-old girls is this pattern reversed, and thedifferences are slight at these older ages.

These white-Negro differences can be com-pared with the corresponding differences forheight and weight of U.S. children and youthsfrom these national surveys. 13 Negro boys wereslightly taller at 7-9 years and white boys wereslightly talIer from 9 to approximately 12 years;Negro girls were consistently talIer than whitegirls were from 7 to 14 years, after which thewhite girls were consistently taller. The meanweights of Negro boys were less than those ofwhite boys at all ages except 13 to 14 years; themean weights of Negro girls were greater thanthose of white girls at 11 to 15 years. It is alsorelevant to note that the Health ExaminationSurvey data yield estimates of median age atmenarche of 12.80 years in white girls and 12.52years in Negro girlsl 4 since age at menarche isknown to be associated closely with the rate ofskeletal maturation.1 5

There is no significant or consistent patternof racialmaturityage span

10

differen~es in variability of skeletalamong either boys or girls across the6-17 years (figure 4). However, Negro

boys and girls tended to be slightIy more vari-abIe in skeletal maturity than white boys andgirls.

Comparisons with other studies in theUnited States. –Some previously reported skele-tal maturity data for white children in theUnited States are shown graphically in figures5-8. These data have been adjusted to a commonGreulich-Pyle zero line to facilitate comparison.This is necessary because there are only quasi-units of skeletal maturity. The data relate tomodal skeletal ages within chronological agegroups, that is, those above the zero line areadvanced (modal skeletal age exceeds meanchronological age) and those below the zero lineare retarded in comparison with the Greulich-Pyle standards. The Greulich-Pyle standards 0were derived from a selected group of whiteCleveland youths of upper socioeconomic statuswho were born between 1917 and 1942 andwere radiographed close to birthdays and half-birthdays. By a painstaking method in whichradiographs were arrayed in order of maturity,within sex- and age-specific groups, one radio-graph was selected as the standard for eachchronological age group because it was con-sidered most representative of the central tend-ency of the skeletal maturity level for the group.This selection was made from 100 radiographsfor each sex at each age.

The mixed longitudinal data of Floryl 6were obtained from white Chicago youths ofabove average socioeconomic status who wereborn between 1904 and 1917. Flory had avail-able 100 radiographs for each sex at each age; allthese radiographs had been taken within 2 weeksof a birthday. From these he selected the radio-graphs he considered best represented the cen-

tral tendencies of his groups. These selected radi-ographs are about 1 year retarded in maturity incomparison with the corresponding Greulich-Pyle standards (figures 1 and 3). Simmonsl 7reported data from white Cleveland youths,most of whom were included among thosestudied by Greulich and Pyle.l 0 These youthswere radiographed near each birthday. The sam-ple size varied from 68 to 198 for each year ofage in each sex. Simmons excluded some girls atolder ages who had surpassed the upper limits ofthe standards. Consequently, the means for girlsat ages beyond 14 years have not been included

20

r

BoYS 20

Iii

h~4\ 15

, \

\$

6

\Ha .

/ \

10 \ \-- .-., 0 ~. . 10-----

\\\\\

6\ Negro

White 5

01 , , , t , I I I o

6 8 10 12 14 16 lB

CHRONOLOGICAL AGE IN YEARS AT LAST 61RTHDAY

GIRLS

\

1 1 1 1 1 t I , I 1 a I 1

6 B 10 12 14 16 lB

CHRONOLOGICAL AGE IN YEARS AT LAST SIRTHOAY

Figure 4. Relative variability in skeletal age (hand-wrist) among white and Negro boys and girls age 6-17 years by chronological age inyears: United States, 1963-1970

+0.6 -

0.0 -

-0.6 -

-1.0 -

aow

.- FIory (1936)18

. . . .. Simmcms(19gl)%7 /..+

_Tcfld (1937) ,../

//

//

%. ..””“%... ,.”

...

,/’ \\

,/’\

---- /’

.,,,,15 17 1s

CHRONOLOGICAL AGE IN YEARS

Figure 5. Differences between skelatal and chronological agas ofboys 12-17 years in studies of Flory (1936),16 Simmons

(1944),17 antiTodd [1937).la

in figure 3 because the proportion excluded isunknown. The means reported by Simmons,after adjustment for the use of Todd standards,were within 0.5 year (skeletal age) of the Greu-lich-Pyle standards at most ages.

In 1937 Toddl 8 published standards derivedfrom a group of white Cleveland youths of all

BOYS

+1.0 -- Fry (1966)2’~g ...... Maresh(1970) M

. . . . Johnston[1962)< ..- Greulich and Pyle (le59)f0y — Lhited States{1966.1970)

------------\ --- ......................

‘\----,,. - .-.~.

.\ ./. . . . . . ------- -.

I 1 I I 1 1 I12 13 14 15 16 17 lB


Figure 6. Differences between skeletal and chronological ages ofboys 12-17 years in studies of Fry (1966),21 Maresh(1970),22 Johnston (1962),19 Greulich and Pyle (1959),10and U.S. youths (1966-1970)

socioeconomic levels. These youths were bornbetween 1915 and 1936 and radiographed neareach birthday and half-birthday. The standardplates were chosen to represent the central tend-encies for skeletal maturity level within age- andsex-specific groups. The sample size within eachgroup varied from 42 to 161. The standards of

11

+1.0

+0.5

0.0

-0.5

-1.0

-1.5

GIRLS

FlorY (19361’6 ,./Z.Z Simmons (lS#)

— Tcdd (1937)

/‘\ ,/’\ \ /

WJI 1 I I I I

12 13 14 15 16 17 18


Figure 7. Differences between skeletal and chronological ages of

girls 12-17 years in studies of Flory (1936),1G Sim-mons(1944,17and Todd (1937)18

Todd were about 0.5 year lower than those ofGreulich and Pyle at 12-14 years; the differenceswere much sma.Ilerat later ages. It is tempting toascribe the differences between the skeletalmaturity levels reported by Todd,l 8 Sim-mons,1 7 and Greulich and Pylel 0 to variationsin socioeconomic status among the groups ofyouths studied by these workers. This leavesunexplained the relative lack of differences atlater ages. This may be due, in part, to the sys-tematic exclusion of youths who were toomature to be assessed.

Greulich and Pylel 0 reported data from theHarvard Growth Study. The group of whiteBoston youths included was of middle socioeco-nomic status, born between 1930 and 1939, andexamined near each birthday. The size of thegroups varied from 63 to 67 for each age in eachsex. The mean skeletal ages (Greulich-Pyle) werevery close to the mean chronological ages.John-stonl 9 reported mixed longitudinal data frommiddle-class Philadelphia white youths bornbetween 1937 and 1955. The major ethnicstrains in this group were Italian and British.z0These youths were radiographed at random

+1.0r

GIRLS

1 ................................+0.5 .-.7, *.:2.-+

iii .,/.,’ ~-

w I ----s. ;. ...... . ,. .

-1

t

---Fry (1966)2’ ~: -1.0 . . . . .. Maresh (1970] ,g< . . . . . Johnston (1962)A~ --- Greulich and Pyle (1959)’0

— United States (1SS6.1970)5 \L(Jg

-1.5

t

12 13 14 15 16 17 18


Figure 8. Differences between skeletal and chronological agesofgirls 12-17 years in studies of Fry (1966) ,21 Maresh(1970),22 Johnston (1962),19 Greukh and Pyle (1959),10and U.S. Youths (1966.1 970)

chronological ages and the group size variedfrom 23 to 50 for each annual interval in eachsex. All the mean skeletal ages for each sex wereabout 0.5 year in advance of the Greulich-Pylestandards.

Cross-sectional skeletal age data from somewhite Nebraska youths of middle socioeconomiclevel have been re~orted.z 1 These children wereborn between 19~2 and 1954 and were radio-grapher at random ages. The group included 25youths of each sex within each annual interval.The means were below the Greulich-Pyle stand-ards in the boys but not in the girls. In each sexthe differences between the mean levels reportedby Fry and those of the Greulich-Pyle standardsdid not exceed 0.6 year. Mareshzz reportedmixed longitudinal data from a group of middleclass white Denver youths. These youths wereborn between 1915 and 1955, but most of theradiographs were taken after 1947 and close tobirthdays and half-birthdays. The group size

12

ranged from 21 to 43 for each 6-month intervalin each sex. The median skeleta.Iages for theseyouths were between 0.5 and 1.0 year below theGreulich-Pyle standards from 12 through 17years, Data have been reported by Malina andJohnston,Z8 . who used Todd assessments ofabout 20 white Philadelphia youths of each sexfor each annuaI interwd from 12 to 16 years.After adjustment to a Greulich-Pyle baseline,their data for boys show an advancement inskeletal age of about 1 year except at 15-16years, when the advancement is 1.6 years. Thegirls, however, are retarded by about 0.5 year.

These previous studies of groups of whiteU.S. youths indicate that sex differences inmean levels were small. This does not mean thatgirls did not mature more rapidly than boys butthat the differences between the mean skeletalages for the two sexes were slight when assess-ments were made against sex-appropriate stand-ards,

The present national survey data for whiteboys, as noted earlier, are markedly below theHES reference standards at 12, 13, and 17 yearsbut not at the intervening ages. These referencestandards were derived from and closely matchthose of the Greulich-Pyle Atlas.10 The levelsand patterns of change across age for white boysfrom the national survey are not in agreementwith those reported from earlier smaller groupsof U.S. white boys.lo~ lG-19~ zl-z~

The mean skeletal maturity levels of whitegirls from the national survey (female equivalentvalues) are best considered in two different ageperiods (12-14 and 15-17 years). From 12 to 14years the mean leveIs are about 0.5 year lowerthan the Greulich-Pyle standards; these findingsare similar to those reported by Todd,l g Fryjz Iand Maresh.z Z However, at later ages (15-17years), the mean female equivalent values forwhite girk from the natiomd survey fall mark-edly behind the Greulich and Pyle standardsuntil the difference is about 18 months at 17years. It must be emphasized that all thenational survey radiographs were assessed againsta single set of male standards. Consequently, thepresent findings probably reflect both real dif-ferences in level between white girls in thenational survey and the Greulich-Pyle standardsand systematic sampling bias in the sex-associ-

ated differences in skeletal maturity levels usedto transform the values assigned to the girlsagainst the male standards when obtainingfema.Ieequivalent wdues.

At 17 years (mean chronological age = 17.5years) the mean skeletal age for white boys is17.1 years and the corresponding mean skeletaIage for girIs (fema.Ie equiwdent values) is 15.5years. The latter value was obtained after trans-forming the mean observed value of 17.6 yearswhich had been obtained using the male stand-ards. The actual difference between the meanvalues assigned to the boys and girls at 17 years,when both were assessed against the male stand-ards, was only 0.5 year. At younger ages theactual sex difference on the male standards wasconsiderably larger; for example, at 12 years thedifference was 2.8 years. This decreasing actualsex difference, at ages after 14 years, leads tomisleading female equivalent values because thesex differences used to obtain the latter weretoo large at these older ages. However, the errorsintroduced by this transformation are systematicand constant across all racial, socioeconomic,and other groupings. This subject is discussed indetail in an earlier reportl and is considered inthe “Discussion” section of this report.

Practically no previous data are availableconcerning the skeletal maturity status of groupsof white U.S. youths of more specific ancestry,nor were such data recorded during the HealthExamination Survey. Toddz 4 reported insignifi-cant differences in maturity status between 315U.S. children and youths, both of whose parentswere born in Italy (usually southern Italy orSicily) and 201 children and youths, both ofwhose parents were born in the United States,most of whom were not of Italian ancestry.These children and youths, who were age 5-13years, were examined cross-sectionally. Fromthis study Todd concluded that the data showedno evidence of race-linked differences although,of course, there were few children in each age-and sex-specific group. Furthermore, he did notcontrol for possibIe socioeconomic differences.

Comparison with forei~ studies. –The avail-able data have been collated concerning theskeletal maturity levels of youths in countriesthat have contributed substantially, by emigra-tion, to the U.S. population. In order, these

13

countries are Germany, Italy, Great Britain(excIuding Ireland), Ireland, Austria-Hungary,Canada, and the U. S. S.R.2s Unfortunately, rele-vant reports are available only for England andPoland.

A major source of information concerningskeletal maturity levels of British youths is thedifferences between Greulich-Pyle and Tanner-Whitehousez632 7 assessments of the same radio-graphs.z1J28‘3 0 These data are relevant irrespec-tive of the specific groups studied. It is importantto note the Tanner-Whitehouse standardizingsample consisted of cross-sectional and serialradiographs of British youths, most of whom werefrom Scotland. The number of subjects per yearfor each sex in the Tanner-Whitehouse standard-izing sample is about 150, but the sample didnot include youths over 16 years. This led toproblems at the upper end of the scalez7Y28which apparently have been remedied to someextent by enlarging the standardizing sample,redefining the criteria for grades, and eliminatingsome grades. This revised system of Tanner andWhitehouse is referred to as “TW-II.”27

The reported findings summarized in table Bconcern studies made using the original Tanner-Whitehouse Method (TW-1). Problems in stand-ardization and rating criteria at the upper end of

the TW-I scale are presumably responsible, inlarge part, for the irregularity of the findings,especially in older girls.

All the reported comparisons show lowermean values for Greulich-Pyle skeletal ages thanfor Tanner-Whitehouse skeletal ages in boys. Ingirls the data are less regular. In the older girlsstudied by Fry2 1 and by Andersen, 28 Greulich-Pyle skeletal ages tended to be higher than thecorresponding Tanner-Whitehouse values. Theo-retically, these variations could be due to differ-ences between the two in the methods ofweighting the bone-specific skeletal ages (orscores). It has been shown, however, that this isnot an important factor.z 9 There is no doubtthat the reported differences almost entirelyreflect variations between the standardizing sam-ples used by Greulich and Pylel 0 and by Tanneret zd.z G To a lesser extent, they may be due tosystematic bias in assessment. Consequently, thedifferences in table B can be interpreted asshowing the variations in skeletal maturity statusbetween the group of white youths in C1evelandand several pooled groups in Britain. As men-tioned earlier, inferences from these data con-cerning the comparative rates of maturation ofyouths in the United States and several pooledgroups in the United Kingdom (U. K.) can be no

Table B. Mean differences in skeletal age (years) between Greulich-Pyle and Tanner-Whitehouse assessments (Gp - TW) of the sameradiographs

Chronological age and sex

Bow

12.0 years .. .. .. ... ... .. .. ... .. ... . ... .. ... .. .... .. .. ... .. ... .. .. .... .. ... ... . ... ... ... .. .. .... ... .. .. .... ... . ... .... . ... .. ...13.0 years ... ... .. .. ... .. . .... .. ... ... . ... .. .. .... .. .. . .. ... .. .. .. .. .. .. .. .. . ... .. .... . ... .... .. ... .. .. .... ... .. ... ... .. .. . ...14.0 years .. .. .. .... ... . .. .. ... .. ... .. .... .. .. . .... .. ... .. .. ... ... .. ... ... .. ... ... ... .. ... . .... .. .... .. ... ... .. .. .... . ... .. .. .15.0 years ... .. .... . ... ... .. ... .. .. .. .... . ... ... .. ... .. ... ... ... ..o.... ... .. .. .. ... .... . .. ... .... .. .. ... ...o.. .. ... .. .. ... ... .16.0 years .. .. .. .. .. ... . ... . ... .. .. .. ... .. .. .. .. .. .. .. .. ... ... .. .. .. .. .. .. .. .. .. .. .. ... ... .. .... .. .. .... . ... .. .. .. ... ... . .. ...

17.0 years .. .. .. .... . ... .. ... .. ... .. .. .... . ... .. .... .. .. .. .. . ... .. .. .. .. .. .. .. .. .. .. .. .. .... .. .. .... .. .. ... ... .. .... .. .. .. .. ..

Girls

12.0 years .. .. . ... ... .. ... ... .. ... .. .. .. .. ... ... ... ... . ... .. .. .... .. .. .. .. .. ... ... .. ... . .... ... . ... ... ... ... .. .. .... .. .. .. .. ..13.0 years ... ... ... .. ... .. . .... .. .. .... .. ..o. .. .. .... .. .. .... ... . .. .... .. .. .. .. .. .. .. . . .. .... .... .. .. .. ... .. ... ... ... .. .. .. ...14.0 years .... . .... .. .. ... ... .. .. .. ... .. ... .. .. .... .. .. .. .... .. .. .. .. .. .. ... .. ... .... .. . ... ... .. ... ... .. ... ... .. .. .... .. .. .. ..15.0 years .. ... ... .. .. ... .. .. ... .. .. .. .. . .... ... . ... .. ... ... . ... .. ... .. ... .. ... ... .. .. .... .. .. ... .... .. ... .. ... .. .. ... ... .. ...16.0 years .... .. .. .. .. ... .... . .. ... ... .. .. ... ... .. .. ... .. ... .. .. .... .. .. .... .. .. .. ... .... .. .. ... ... .. ... .. ... ... .. ... .. ... .. ..17.0 years . .. .. ... . ... .. ... .. .... .. ... . .. .... .. .. .. .. .. .. .. .. .. .... .. .. .. . ... .. ... . .. .. .. .. .. . .... ... .. .. .. .... .. .. ... ... .. .. .

Andersen, Rocha et al., Clark,

19%1 196828 197129 19743’J

Mean difference

-0.9-0.7-0.4

. . .

. . .

. . .

0.0+1.1+’0.5. . .. . .. . .

-0.3-0.7-0.7-0.4-0.5-0.4

-0.50.0

+0.2+1.1+1.7

. . .

-0.5-0.4-0.1

. . .

. . .

. . .

-0.7-0,5-0.5. . .. . .. . .

-1.0. . .. . .. . .. . .. . .

. . .

. . .. . .. . .. . .. . .

NOTE: Fry–Nebraska, white youths; Andersen-Danish youths in Copenhagen; Roche et al.–Australian youths of British ances-try; Clark-Saskatchewan youths.

14

more than tentative because neither the Greu-lich-Pyle nor the Tanner-Whitehouse scale isbased on a representative national sample.

When the levels of skeletal maturity in U.S.and U.K. youths are compared by consideringthe reports of investigators who applied both theGreulich-Pyle and Tanner-Whitehouse methodsto the same youths, the groups studied are irrele-vant except in regard to sample size, which will,of course, af feet the reliability of the estimates.Fryz 1 studied 25 youths of each sex at eachannual interval; this study has been describedearlier. The group studied by Andersenzsincluded about 50 Copenhagen youths of eachsex at each annual interval. Mixed longitudinaldata from 23-51 Australian youths at each yearof age have been reported by Roche and hiscoworkers.z g Clarks O assessed 12 youths at 12years. All the means reported by Andersen indi-cate slight retardation (0.2 to 0.7 year) of theBritish standardizing group in comparison withGreulich-Pyle standards, except in girls at 14-16years (0.2 to 1.7 years advanced). The differ-ences reported by othersz 1$28‘30 are similar forboys. However, Fryz 1 and Andersen,z 8 unlikeRoche et al.,29 found the Greulich-Pyle skeletalages were more advanced than those of Tanner-Whitehouse in girls age 14 years or older. In gen-eral, these studies indicate that the standardizingsample of boys of Tanner et al.z 7 was about 0.5year behind the Greulich-Pyle standardizing sam-ple in mean skeletal maturity level, but the dif-ferences among these reports preclude any gen-eralization for girls. Paradoxically, when a groupis given a higher mean rating on the Tanner-Whitehouse scale than on the Greulich-Pylescale, this shows that the standardizing groupused to construct the Tanner-Whitehouse scalematured more slowly than the group used toconstruct the Greulich-Pyle scale.

Further evidence concerning the skeletalmaturity levels of British children is availablefrom the mixed longitudinal data of Roche31obtained from essentially the same group ofAustralian children of British ancestry as thatstudied by Roche et al.z 9 The size of this groupranged from 42 to 51 for each sex at each yearof age. The mean Greulich-Pyle skeletal ages inthese Australian youths were very close to themean chronological ages, within 0.2 year. This

suggests that youths of British ancestry born andliving in Australia mature slightly more rapidlythan British youths living in Great Britain.

Kopczynska3 z reported cross-sectional datafrom about 6,000 Polish youths age 12 to 16years living in Warsaw. The mean skeletal ages(Greulich-Pyle) tended to be less than the meanchronological ages, especially in the boys.

Other comparisons. –The literature allowsonly tenuous comparisons between reportedskeletal maturity levels of groups of white andNegro youths in the United States. Toddz 4using cross-sectional radiographs of 149 Negrochildren and youths (age range not reported)tentatively concluded there were no modal dif-ferences in skeletal maturity level betweenNegro and white boys but that Negro girlstended to be more advanced than white girls.

Malina3 3‘36 and Malina et al.36 made Tan-ner-Whitehouse assessments of some middle to

upper-middle socioeconomic class white youths(IV = 35) and some lower socioeconomic classNegro youths (IV = 168) in Philadelphia, age 12to 14 years. Both groups of youths were slightlyin advance of the Tanner-Whitehouse standardsexcept at 12 years in girls, when the differencewas very small. The differences between themeans for the two groups (white and Negro)were small, but the Negroes were slightly moreadvanced (O. 1 year, boys; 0.4 year, girls) despitethe lower socioeconomic status of the Negrogroups. These findings suggest that, at the samesocioeconomic level, the skeletal maturity statusof Negro youths may be slightly in advance ofthat of white youths.

Cross-sectional data have been reported from139 rural Jamaican youths age 12 to 16 yearsliving about 15 miles northofKingston.37 At allages, the mean Tanner-Whitehouse skeletal ageswere less than the mean chronological ages.These differences tended to increase with agebecoming comparatively large in girls between14 and 16 years (table C). These Jamaicanyouths were retarded skeletally in comparisonwith the Negro youths in Philadelphia studied

by Malina.3 3‘3 4 ~3f’ Michaut-Barthod38 reportedGreulich-Pyle skeletal ages for Dakar youths ofOvoloff ethnic origin. The group size rangedfrom 18 to 60 for each sex within 6-month age

groups. These youths were markedly behind the

15

Table C. Modal differences between skeletal age and chron-ological age (S.A. - C.A. in years) in some Negro youths inother countries

Chronologicalage and sex

Boys

11.5 years .. ... .. ... .. ... .. .. .. ...12.0 years .. ... .. .... .. .. .. ... ... .12.5 years .... ... .. .. .. ... .... ... .13.0 years .... . ... .. ... .. . .. ... .. .13.5 years ..... .. .. .. .. .. . ... .. ...14.0 years .... . .. ... ... . .. .... ... .14.5 years .... .. .. .. ... ... . ... ....

15.0 years ... .. ... . ... .. ... .. ... ..15.5 years ..... ... ... .. .. .... .. .. .

Girls—

11.5 years .. .. .. .... .. .. ... .. ... ..12.0 years .. .. .. .. .. .. .. .. .. ... . ..12.5 years . .. . .. ... .. ... ... .. .. ...13.0 years ... ... .. .. .. ... ... . ... ..13.5 years ... ... ... .. ... .. .. ... ...14.0 years .... ... .. .. .... .. .. ... ..14.5 years ... .... .. .. .. .. .. .... .. .15.0 years ..... . ... ... ... . .. ... ...15.5 years ... .. .... .. . ... .. .... .. .

Modal difference

-0.2. . .

-0.7. . .

–0.7. . .

-0.8. . .

-0.8

-0.6. . .

-0.4. . .

-0.5. . .

-1.1---

-1.7

. . .-1.3-1.3-1.4-1.2-1.1-1.2

-1.1. . .

. . .

-7.7–1.3-1.8-1.4

-1.6-1.6–1.8

..-

NOTE: Marshall et al.–rural Jamaican youths (Tanner-Whitehouse Scale): Michaud-Barthod–Ovoloff youths in Dakar(Greulich-Pyle Scale),

Greulich-Pyle standards. The mean differencesbetween the chronological and skeletal agesranged from 1.1 to 1.8 years, tending to begreater in girls. When adjustments are made forthe differences in rating scales used, it becomesclear that skeletal maturation was markedlydelayed in the Dakar youths compared withthose in Jamaica. But as noted earlier, skeletalmaturation was also delayed in the JamaicanNegro youths compared with those in Philadel-phia.

Cross-sectional data from 3,624 southernChinese youths in Hong Kong who were bornbetween 1944 and 1950 have been reported 39(table D). Greulich-Pyle assessments showed amarked tendency to skeletal retardation in theseChinese boys at 12 and 13 years, but later themean differences between chronological andskeletal ages were small. This tendency to lesserdelay in skeletal maturity in the boys as ado-lescence proceeded may reflect genetic differ-ences between the groups studied by Low etala g and Greulich and Pylel O in a~e-associatedrates of skeletal maturation. From 12 to 15

Table D. Modal Greulich-Pyle skeletal age levels (S.A. - C.A. inyears) in southern Chinese youths


Boys

12.0 years ... ... ... . .... ... ... . .... .. ... .. ... .. ... .. .. .... . .13.0 years .. ... .. .. ... ... .. ... .. ... .. ... ... .. ... .. ... ... . ...14.0 years .. .. .. .. .. ... ... ... .. .. ... .. ... ... ... .. ... . .... .. .15.0 years .... .. .. .. . ... .. ... .. ... . ..... . .... .. .. .... . ... .. .16.0 years .. .. ... ... .. ... ... ... . ... .... .. .. ... ... .. .. ... .. ..17.0 years .. .. .. .... .. . .... . .... .. .. .. ..... .. . .... .. .. .. . ...

Girls

12.0 years . ... .. ... . .. ... .. ... ... .. .. .... . ... .. ... .... . .. . ..13.0 years .... .. ... . ... .... . .. ... ... ... .. .. ... ... .. .. ... .. ..14.0 years ... ... .. .. .. .. .. .... .. .. .. .... .. .. ... ... .. .. .. .. ..15.0 years .... .. .. .. .. .... .. .. .. ... ... .. ... ... .. ... ... .. .. ..

16.0 years .. ... . ... ... .. ... .. ... ... . ... ... .. ... ... ... ... .. ..17.0 years ... .. ... .. ... ... .. .. .. ... ... .. ... ... ... .. ... .. ... .

Low et al.,196439

Modal skeletal age

-1.1-1.5-0.2+0.2+’0.7+0.6

+0.1+0.3+0.4+0,4

+0,5+0.1

years, however, it might also reflect the demon-strated differences between the Greulich-Pyleskeletal maturity levels and those present in thenational probability sample of U.S. white andNegro boys. The Chinese girls studied by Low etala g tended to be very slightly advanced skele-ta.lly in comparison with the Greulich-Pylestandards at all ages from 12 through 17 years.This is different from the findings of the presentsurvey of U.S. white and Negro girls who werebehind the Greulich-Pyle standards during thesame age range.

Greul.ich40 reported cross-sectional datafrom a “representative sample” of Americanborn youths of Japanese ancestry living in theSan Francisco area of California (table E). Thissample included 20 to 41 youths of each sex ateach annual interval who had been born between1939 and 1944. The mean skeletal ages41 ofthese Japanese-American youths were advancedover their mean chronological ages for all agegroups in each sex. In the boys, these differenceswere small except at 16 years, but in the girlsthe y were large from 13 through 16 years.Sutow4 Z reported cross-sectional data fromJapanese youths in Hiroshima who were bornbetween 1936 and 1941 and examined within 1month of a birthday. These youths constitutedthe normal control group when irradiationeffects were being studied in Hiroshima youths.The group sizes varied from 56 to 107 for eachsex at each age. Standards were selected from

16

Table E. Modal skeletal age levels (S.A. – C.A. in years) ofAmerican youths of Japanese ancestry40 and Japanesevouths in JaPan42’43

Chronologicalage and sex

BOVS

12,0 years ........................12.5 years ........................13.0 years ........................13.5 years ........................14.0 years .............. .. ........14.5 years ........................15.0 years ........................15.5 years ........................16.0 years ........................16.5 years ........................17.0 years ........................

Girls—

12.0 years ........................12.5 years ........................13.0 years ........................13.5 years ......... ...............14.0 years ........................14.5 years ..................... ...15.0 years ........................15.5 years ........................16.0 years ........................16.5 years ........................17.0 years ........................17.6 years ........................

Modal skeletal age

+0.4. . .

+0.6..-

+0.6. . .

+0.5. . .

+1.2-..

+0.5

+0.6---

+1.4-..

+1.0---

+1.0. . .

+1.1---

+0.6. . .

-1.0. . .

-0.6. . .

-1.2-..

-1.0.-.

-1.5-..

-1.0

-1.2---

-2.0. . .

-1.5-..

-1.5. . .

-1.5.-.

–2.0---

-

----0.5

-..

0.0---

0.0---

0.0..-

+0.5. . .

---

-0.5-..

0.0. . .

–0.5---

-0.5---

-0.5..-

-0.5

these radiographs by a procedure similar to thatused by Greulich and Py1e44 and these standardswere a&essed against the Greulich-Pyle Atlas bySutow.A z These assessments show that, by com-parison with the Greulich-Pyle standards, themodal levels of skeletal maturity were low inthese youths, particularly in the girls, in whomthe mean retardation exceeded 1 year at eachannual age interval.

These data of Greulich and Sutow showmarked differences between the skeletal matur-ity levels of American youths of Japanese ances-try and Japanese youths in Japan, with the for-mer being the more advanced. It must bestressed that these data were derived fromyouths born between 1936 and 1944; the cur-rent differences may be smaller.

That such a secular change has, in fact,occurred is shown by recent findings. The skele-tal maturity standards of Sugiura and Naka-zawaA 3 indicate that Japanese youths living inNagoya have median skeletal ages that are now

very close to the Greulich-Pyle standards. Simi-larly, Ashizawa4 E reported Tanner-Whitehouseskeletal ages for Japanese youths living inTokyo. The means for the boys were about 1year in advance of the Tanner-Whitehouse stand-ards, but the corresponding differences for thegirls were very small. If transformed to a Greu-lich-Pylel 0 baseline, this would imply that theboys were about 0.5 year in advance of theGreulich-Pyle standards and that the girls wereabout 0.5 year behind them. Kimura46 reportedmean Tanner-Whitehouse skeletal ages for 137Japanese youths age 12-17 years. These wereabout 0.5 year in advance of the mean chrono-logical ages in each sex, implying that the meanlevels would have been close to those of theGreulich-Pyle standards.

As suggested by Greulich,40 it is reasonableto conclude that the differences between theskeletal maturity levels of youths of Japaneseancestry in California and those living in Japanin the 1950s are likely to be environmentallydetermined although the possibility of selectivemigration cannot be excluded. The more recentfindings of Sugiura and Nakazawa,43 Ashi-zawa,zs and Kimura46 suggest that these earlierdifferences have been greatly reduced, if noteliminated. This rapid change supports the viewthat the difference; reporte~ earii& were Iarzely.environmentally determined. They are als~ inagreement with changes in rates of growth andsexual maturation occurring in Japan in recentdecades that have been reported in otherstudies.4 T‘4 g

One can infer, however, that genetic factorsare also involved in differences between meanskeletal maturity levels of Japanese youths andU.S. white youths from data provided byKimura.s0)51 He reported that skeletal ageswere less advanced in a group of male Japaneseyouths than in a group of hybrid Japanese-American youths. The members of both groups

had been reared and cared for in the same Japan-ese orphanage environment.

Variability of skeletal ages. –The standarddeviations of the various reported skeletal agesfor ,groups of U.S. white youths can be used as agau~e of variability to compare earlier findingswith those in the national survey (table F).There is considerable agreement among thestudies of white youths, although the groups

17

Table F. Standard deviations (Years) Of skeletal a9e for United States youths

Flory, Johnston, Fry, Malina,l Malina,2United States

Age and sex193616 %% 196219 196621 197053 197053 White Negro

Boys

12 years .............................................................13 years .............................................................14 years .............................................................15 years ........o...................o.............................l..16 years .............................................................17 years .............................................................

Girls (female scale or equivalent)

12 years ................................................... ..........13 years .............................................................14 years ........ .....................................................15 years .............................................................16 years .............................................................17 years .............................................................

1.00.81.11.11.11.1

1.11.10.90.80.70.6

0.90.91.01.11.21.2

1.11.21.31.10.90.7

0.70,91.01,00,91,1

1.11.20.91.20.90.5

Standard deviation

1.41.50.9. . .. . .. . .

1.41.21.3. . .. . ...-

1.1. . .. . .. . .. . .. . .

0.9.-...-.-.. . .. . .

1.20.9. . .. . .. . .. . .

1.11.1. . .. . .. . .. . .

1,41.51.21.21.10.9

1.00.90.70.70.70.7

NOTE: Flory, Bayley, Johnston, Fry-white youths; Malinal–white Philadelphia youths; Malina2–Negro Philadelphia youths.

studied differed in socioeconomic variability andin their range of chronological ages. There is,however, a slight tendency for the standard devi-ations from the national survey to be larger thanthose reported by others for boys 12-15 years; asimilar tendency is not present in the data forgirls.

At all ages, the national survey data for bothwhite and Negro youths indicate that skeletalmaturity levels are less variable, judged by thestandard deviations, in girls than boys. Thewhite-Negro differences in variability are negli-gible (table F). Within the other reportedstudies, a tendency to a similar sex differencewas present only at the oIder ages.1G~19~szThese sex differences at the older ages may onlyreflect the truncated distributions caused bymany girls reaching the maximum values thatcan be assigned.

When the variability of skeIetal ages is com-pared between the white and Negro groups inthe national survey, in terms of the coefficientof variation (figure 4), it is clear that Negro boystend to be considerably more variable thanwhite boys except at 12 years. The pattern ofdifferences between the white and Negro youthsis less consistent in the girIs; the mean skeletalages are more variable in the white girls at 13,15, and 16 years but less variable at 12, 14, and17 years. This lack of a consistent pattern in thefindings for boys and girls in the coefficient of

1.31.61.41.31.40.9

1.10.80.90.60.70.8

variation might reflect the comparatively smallsamples of Negro youths. Long ago, Toddz 4considered, after amdysis of data from a smallergroup, that skeletal maturity was more variablein American Negroes than whites. The presentfindings provide limited support for his view.

Reported standard deviations for the groupof Australian youths studied by Roche31 aresmaller than those for the national surveyyouths; however, those reported by Low et a.1.t9for Chinese girls are larger (table G). Much ofthese differences could reflect variationsbetween these studies in the scheduling of exam-inations. The Australian youths were seen veryc1os e to birthdays and half-birthdays, theChinese children and the U.S. survey childrenwere examined at random chronological ages.The latter procedure would have increased themeasures of variability. Furthermore, there wasa much wider range of socioeconomic status inthe group of Chinese youths than in the Austra-lian youths and possibly even the national surveyyouths. This also would tend to increase thevariability. The variability of skeletal ages in thegroups studied by Andersenz 8 and Marshall andhis associates y is similar to that found in thenational survey. As in the national survey, varia-bility tended to be less in older girls in thegroups studied by Low and his coworkers 9 andAndersen.z 8 The data of Marshall and hisassociates y show a tendency to less variability

18

Table G. Standard deviations (years) of skeletal age in groups of youths outside the United States


Boys

12,0 years .... .... .. ... .. ... ... ... .. ... .. ... .. ... ... ... .. .. .. .. . ... .. .... .. ... . ... ... .. ... . .. .. ... . ... .. ... .. ... ... .. .12.5 years .. .... ... .... .. ... .. .. ... ... .. ... .. ... .. .. ... .. .. .... ... .. .... .. .. .. .. .... .. .. .. .... . ... .. .. .... . .... .. ... . .13.0 years ... . ... ... ... .. ....m.m.. ... ... . ... .. ... ... ... .. .. .. ... ... .. ... ... .. ... .. ... .. ... .. ... .. .. .. .... .. .. .. ... ... .13.5 years ... .. .... ... .. .... .. .. ... .. .... .. ... . .... ... .. .. .. .. .... .. ... ... .. .. .. .. .... .. ... .. ... ... .. .. ... .. .. ... ... ..14,0 years .... .. .... ... ... .. ... ... .. .. ... .... . .. .... .. .. ... .. .... .. .. ... ... .. ... .. .. .... . ... . .... . ... ... ... ... . ... .. ..14.5 years ... ... .... .. ... .. ... .... . ... ... .. .. ... ... .. ... .. .. ... ... .. .... . ... ... .. ... .. .. .. ... ... .. .. ... ... .. ... .. ... . .15.0 years .... .... .... . ... ... .. ... .. .... . ... ... . .... .. .. ... .. ... .. .. ... .... .. . .... . .... . ... ... ... .. .. .. ... .. .. ... ... ..15.5 years ... .. .. .. .... .. .... . .... . ... .... ... . ... .. .. ... . .... .. ... . .. .... .. ... .. ... .. .. ... .. ... ... .. ... .. .. ... .. ... ...16.0 years ... ... ... .. ... .. .... ... .. .. ... .. .... . ..... . ... .. ... .. ... ... ... ... .. .. ... . .... .. .. ... .. ... .. ... .. .. ... ... ... .16.5 years ... .. .... .... . .. ..... .... .. ... ... .. .. ... ... . ... .. .. ... .. ... .... .. .. .. ... ... .. ... . ..... . ... .. ... .. .. .... . ....17.0 years .. ... .... .... . .. ... ... .. . . ... .... .. .. ... .. ... .. .. .. .... .. .. .... .. .. .. ... .. ... .. .. ... .. .. ... ... .. ... ... .. .. ..17.5 years ..... .. ..m... . ... .... ..m. .. ... ... .. .. . ... .. ... . ... ... .. ... .. .... .. .. .. .. ... .. ... .. ... .. .. .. ... ... .. .. ... ... .

Girls

12.0 years .. .. ..... .. ... . .... ... ... .. .. .... .. . .... .. .. .. ... .. ... ... .. ... .. ... . ... .. ... .. .. ... .. .. ... .. .. ... ... .. ... . ..

12.5 years ... ,.,, .,,..!.,. ... ... ... ... ... .. .. .. .. .... .. .. .. .. ... ... .. ... ... .. .. .. ... .. ... . .... ... . ... ... .. .. .. .. .... ..13,0 years .... ... ... .. ... ... ... .. ... .. ... ... .. .. ... .. ... .. ... ... .. .. ... ... ... . .. ... .. ... . ... .. ... .. .... .. .. .. ... .. ... .13.5 years ... ... .... .. ... .. .. . .. .. .... ... . .... .. .... . .. . .... ... . .. . ... .. ... .. .. .. ... .. .. ... ... .. .. .. .. .... . .... . ... ...14.0 years ... .... .. ... ... .. ... ... ... .. .. .... .. .. .. .... .. .. .. ... ... . .... .. .. . .. .. ... .. .. .. .. .. .. .. ... .. ... .. .. .. .... .. .14.5 years ... .. ... .. .. .. .. .... ... . .. .. .. .. ... .. ... ... .. .. .. ... ... .. . .... ... . .. .... .. .. ... .. .. .. ... .. .. . ... .. .. ... .. ...

15.0 yaars .... ..o. .. .. .. ....o. ...o. ... .. .. ... ... .. ... .. .. ... ... ... .. ... ... .. .. .. ... ... .. .. .. ... .. ... .. . ... . .. .. ... .. ..

15.5 years ... ...mm...o.. ... .. . .. ... .... .. .. ... .. ... . ... . ... ... ... .. ... .. ... .. .. ... .. .. .. ... ... .. .. .. .. .... . ... ... ... ..

16.0 years ... ... ... ... .. .. ... .. .. .. ..... ... . ... ... .. .. .. .. ... ... ... .. ... .. .. .. ... .. .. ... .. ... ... .. .. ... .. .. .. .. ... ... .16.5 years .... .... .. .. .... .. .. . ... .. .. .. .. .. .. .. .. ... .. ... .. ... ... .. .. ... .. .. .. ... .. ... .. ... ... . ... . .... .. ... . .. .. . ...17,0 years ..... .... .. ... .. . .. .. ... ... .. ... ... ... .... .. .. .... .. .. .. .. .... .. ... . .. .... .. . ... .. .... .. .. .. ... .. .. ... .. ....

17.5 Vaars ... .. .... .. .... .. .. . .. .. .. .. .. ... .. .. ... ... .. .. . .. . .. .. .. .. .... . ... .. ... ... .. . ... ... .. .. ... .... .. .. .. .. . ... .

Standard deviation

0.7. . .

0.7. . .. . .. . ...--..

. . .---. . .---

0.8. . .

0.8---..-. . .-..

. . .

.-.

..-

.-.---

. . .0.9-..

0.8---

1.0.-.

1.1. . .

1.0---

1.0

. . .

0.9. . .

1.1.-.

1.1. . .

1.1. . .

0.8..-

0.7

1.3---

1.5. . .

1.3.-.

1.0. . .

1.4..-

1.6-..

1.3---

1.3..-

1.1. . .

1.3. . .

1.0.-.

0.8---

Marshall et al.,197037

---1.2. . .

1.6.-.

0.8.-.

1.1. . .

..----..-

. . .0.7. . .

0.5---

0.6.-.

0.6-...-.. . .---

NOIE: Roche–British youths in Australia; Andersen-Danish youths; Lowetal.-Chinese youths; Marshall etal.-Nego youthsinJamaica.

in Negro Jamaicans than in U.S. Negro youths.This may reflect a relatively homogeneous andlow socioeconomic level in Jamaica.

Geographic Region

Analysis of the national survey data by geo-graphic region shows that for all racial groupscombined, youths in the South are slightly moreadvanced skeletally and those in the Midwest areless advanced in this aspect of development, on

the average, than those in either the Northeastor West Regions of the United States (table 2).This regionzd differential is present among bothboys and girls over the total age span 12-17years but is not consistent at the individual yearsof chronological age and may be confounded byunequal racial distributions (figure 9). It isemphasized, however, that these regional differ-ences are small. The total regional differencesfor either sex do not exceed the 95-percent con-fidence limits for such estimates from this study.

The four regions into which the United Stateswas arbitrarily divided for sampling and adminis-trative reasons in this national survey are so largegeographically and so heterogeneous that anyreal differences among smaller regions that mayexist in the skeletal maturity of youths withinthis country would probably be masked.

Mean skeletal ages (hand-wrist) of boys age12-17 years (mean chronological age of 15.0years or 180 months) range from 14.7 years(175.9 months) in the South to 14.5 years(174.0 months) in the Midwest. However, forgirls (assessed against the male standards) thevalues range from 16.5 years (19 7.5 months) inthe South to 16.3 years (196.0 months) in theMidwest.

Among boys, the mean skeletal ages forthose in the South exceed those in the otherthree regions of the country only at chronolog-ical ages 12 and 16 years; at ages 12, 14, 15, and16 years the mean skeletal ages of those in the

19

+5

o

-5

-lo

-15

-20

-25

BOYS

Northeast

----- Midwest

‘---- South

------ West.

1 1 I I 1 I 1 1 I I 1 1 I I

6 B 10 12 14 16 lB

CHRONOLOGICAL AGE IN YEARS AT LAST BIRTHDAY

+5

o

-5

-lo

-15

-20

-25

GIRLS

\,.

\

‘<,,

v

— Northeast

----- Midwest

‘---- South

.............. .... West

1 I I I I I I I 1 I I I t I

6 8 10 12 14 16 18


Figure9. Mean difference in months between skeletal age(hand-wrist) andchronological age for boys andgirls age6-17years by regionand chronological age in years: Unitad States, 1963-1970

Midwest are lower than elsewhere in the UnitedStates.

For girls at chronological ages 15-17 years,the mean skeletal ages of those in the Southexceed those in the other three regions; how-ever, only at age 12 years are girls in the Mid-west less skeletally mature, on the average, thangirls living elsewhere in this country.

If the age-specific mean skeletal ages forboys in the four regions combined applied ineach individual region, boys in the South wouldbe expected to be the most skeletally mature(on the basis of the chronological age distribu-tion) and those in the Northeast, rather than theMidwest, would be expected to be the leastskeletally mature, on the average. When theexpected skeletal ages (on the basis of chrono-logical ages) are determined for girls, those inthe Midwest would be expected to be the leastskeletally mature, and those in the South andWest would be most advanced, on the average.

The negligible difference between the actual andexpected mean values in each region indicatesthat differences in the chronological age distri-bution of boys or girls among the regions prob-ably account for much of the actual but smallmean regional differences in skeletal maturityamong youths in the United States (figure 10).

The variability of skeletal maturity, as meas-ured by the standard deviation (table 2) or inter-quartile range (tabIe 8), tends to decrease withincreasing chronological age among youths (boysand girls) in each region.

The regional pattern of skeletal maturityamong youths age 12-17 years is more consistentand different from that found among childrenage 6-11 years in the preceding national survey.3Boys age 6-11 years in the Northeast are themost skeletally mature and those in the Souththe least advanced in this respect. Among girlsage 6-11 years, the mean values are highest inthe Midwest and lowest in the West, though, as

20

I Northeast Midwest South West

1 =,.,,,,,,,~ 12.17 years

GIRLS

Fiaure 10. Difference between actual and expected mean skel-.etai age (hand-wrist) for boys and girls 6-17 years ofchronological age by ragion: United States, 1963-1970

in the youth survey, all these mean values arewithin the 95-percent confidence limit for suchestimates (not statistically significant).

When white youths only are considered,boys age 12-17 years in the South are slightlymore advanced skeletally and those in the Mid-west slightly less advanced in this respect, on theaverage, than boys living elsewhere in theNation. Among girls age 12-17 years, those inthe South are also slightly more advanced andgirls in the Midwest slightly less mature skele-tally than girls living elsewhere in the UnitedStates (table 3 and figure 11). The mean valuesfor white boys age 12-17 years (mean chronolog-ical age of 15.0 years or 180 months) range from

14.8 years (177.3 months) in the South in 14.5years (174.2 months) in the Midwest and forwhite girls from 16.5 years (197.5 months) inthe South to 16.3 years (195.9 months) in theMidwest. All these values are for assessmentsagainst the maIe standards.

The regional pattern for skeletal maturityamong Negro youths differs somewhat from thatamong white youths. Negro boys age 12-17years in the West tend to be more skeletallymature and those in the South less skeletallymature, on the average, than Negro boys livingin the other regions. Negro girls in the Midwestare more skeIetaIIy mature and those in the Westless skeletally mature than Negro girls living else-where in the Nation. The mean skeletal agevalues for Negro boys age 12-17 years (meanchronological age of 15.0 years or 180 months)range from 14.6 years or 174.9 months for thosein the West to 14.3 years or 172.0 months forthose in the South; among Negro girls in thesame age range the values range from 16.5 yearsor 197.8 months in the Midwest to 16.4 years or196.2 months in the West.

Urban-Rural

There is no consistent pattern of urban-ruraldifferences in skeletal maturity among eitherboys or girls in the youths’ age range in theUnited States (table 4). This finding is similar tothat for children 6-11 years old in the previousnational survey.3 Unlike the situation in someother countries, this implies a relative lack ofdifferences between urban and rural areas of theUnited States in the genetic and environmentalfactors that influence the rate of skeletal matu-ration and physical growth in generals 4

The mean skeletal age (hand-wrist) for boysage 12-17 years (mean chronological age of 15.0years or 180 months) in either urban or ruralareas is 14.6 years or 174.9 months. For girls themean values (male standards) in both the urbanand rural areas are 16.4 years (196.6 months,urban; 196.5 months, rural).

For both boys and girk in urban areas, themean values are slightly higher for those living inthe largest (3 million or more) urbanized areas.For those living in rural areas, there are no con-sistent differences dependent on whether they

21

Figure 11. Difference between actual and expected mean skeletal age (hand-wrist) for white and Nagro boys and girls 6-17 years ofchronological age by region: United States, 1963-1970

live on farms or dependent on the size of thenon farm community in which they live.

Family Income

There is no consistent relationship betweenthe skeletal maturity levels of youths age 12-17years in the United States and the size of theirfamily income (table 5 and figure 12). However,those from the higher income levels of $10,000and over per year appear to have slightly, butnot significantly, higher mean values than thosewith lesser incomes.

Among boys age 12-17 years (mean chrono-logical age 15.0 years or 180 months), the meanskeletal age (hand-wrist) for those with annualfamily incomes of $10,000 and over is 14.6years or 175.5 months compared with 14.5

years (174.5 and 174.6 months) in the twobroad income groups below $10,000

($5,000-$9,999; under $5,000). If only those inextremes of the income distribution are con-sidered, the mean skeletal age (hand-wrist) ofboys in families with $15,000 or more annualincome is nearly identical with that for theentire group with $10,000 and over income(175.8 months compared with 175.5 months),while among those with annual family income ofless than $3,000 the mean skeletal age is slightlyhigher than for all those in the bracket under$5,000 (175.6 months compared with 174.5months). The difference (all ages combined)between those with annual family incomesgreater than $15,000 (175.8 months) and thosewith annual family incomes less than $3,000(175.6 months) is trivial.

22

+5r BOYS GIRLS

0

-6

10

-15

-20 — Less than $5,000

I ------ $5,000.$9,999

I ----- $l0,0000rmOre

-26

rt I I I 1 r I I I I I t I

6 6 10 12 14 16 18

CHRONOLOGICAL AGE IN YEARSAT LAST BIRTHDAY

+5

o [

-5 —

-10 —

-15

-20 — Lessthan $5,000

-----$5,000.$9,999

----- $l0,0000rmOre \

I I I I I I I I I I I I I J

6 8 10 12 14 16 18

CHRONOLOGICAL AGE IN YEARSAT LAST BIRTHOAY

Figure 12. Mean difference in months between skeletal age (hand-wrist) and chronological age for boys and girls age6-17vearsbvannual family income andchronological age in years: United States,-1963-1970 - - - -

A nearly similar pattern ofassociation existsbetween family income and the skeletal matur-ity of girls age 12-17 years (mean chronologicalage 15.0 years or 180 months). The mean skele-tal age is greatest among those with an annualfamily income of $10,000 or more (16.5 yearsor 198,1 months) and about the same (16.3years) in the two broad lower income groups. Atthe extremes of the income ranges, the meanskeletal maturity level of those with a yearlyfamily income of $15,000 or more is 197,9months or just slightly less than the mean of198,1 months for all those with a yearly familyincome of $10,000 or more. As for boys, at thelowest income level ($3,000 a year or less) themean skeletal age of girls (male standard) is197.0 months, which is slightly greater than forall girls in families with annual incomes under$5,000. Despite this lack of a clear-cut associa-tion with income when all ages are combined, itis clear that in the girls, but not the boys, thosewith annual family incomes in excess of $15,000

were considerably more mature than those inlower income groups at age 14-17 years.

When the effect of differences in the chrono-1ogiczil age distribution among the variousincome level groups is removed, boys age 12-17years in the highest income level famiIies($1 OJJOO a year and over) are slightly moreadvanced skeletally than expected and those inthe lowest income level group (under $5,000)are less advanced than expected in this respect;the differences are slightly more marked thanamong younger boys age 6-11 years, but notlarge enough to possibly reflect more than theeffect of sampling variability (figure 13). Thepattern of deviation in skeletal maturity from

that expected among girls 12-17 years acrossincome differs somewhat from that shown forboys and younger girls, but the differences againare negligible.

Because of a possible confounding effect ofracial differences on the preceding analysis ofincome-related variations, the national survey

23

-i:z~ozn~u! Less than S5,0Q0 $5,000.$9,999 $10,OCQor more%.

g +5 _

$GIRLS

0~

.w<A$

!5

;

z$ 0z0:

Less than $5,000 $5,000-$9,999 S1 0,000 or more1+x

:g

Figure 13. Difference between actual and axpected mean skel-etal age (hand-wrist) for boys and girls 6-17 Years ofchrono-logical age by annual fa”mily inc;me: United States,

1963-1970

data have been considered separately for whitesand Negroes. Among white boys age 12-17 yearsthere is even less association between skeletalmaturity level and family income than thatnoted for boys of all races combined (table 6).The mean skeletal age values are identical forthose with $10,000 or more and those withunder $5,000 annual family income (175.4months) and nearly identical (175.5 months)with those in the family income bracket of$15,000 and over. Furthermore, boys in thelowest income level families, less than $3,000reported annual income, have slightly highermean levels (176.4 months) than the others.

White girls appear to show an association be-tween skeletal maturity and family income simi-lar to that for girls of all races combined–slightly higher means for those in the upperincome IeveIs.

Both Negro boys and girls age 12-17 years inthe higher income level families ($10,000 ormore per year) are slightly more advanced skele-tally than those in families with income levelsbeIow $5,000. Mean skeletal age for Negro boys(mean chronological age 15.0 years or 180months) in families with incomes of.$ 10,000 ormore is 14.6 years or 175.8 months comparedwith 14.4 years or 172.6 months for those infamilies with incomes of under .$5,000. ForNegro girls there is a large difference betweenthe mean skeletal ages (male standard values) forthose in families with $10,000 and over annualincome (17.2 years, 206.6 months) and the cor-responding ages for those in the bracket under$5,000 (16.4 years, 196.7 months). At theextremes of family income considered, the meanskeletal age for Negro boys was markedly higher(15.6 years, 187.8 months) for those in familieswith incomes of $15,000 or more than for theentire group in families with incomes of.$ 10,000or more (14.6 years, 175.8 months). However,the mean skeletal age was also slightly higheramong those with family incomes less than$3,000 (14.5 years, 174.2 months) than for theentire group with family incomes less than$5,000 (14.4 years, 172.6 months). AmongNegro girls, the pattern of differences betweenmean skeletal ages and family income were evenless consistent. To some extent, the inconsist-encies in each sex might reflect the effect ofsmzdl samples sizes at the extremes of the distri-bution of family incomes.

The mean skeletal ages of Negro boys wereslightly lower than those for white boys age12-17 years in families with less than $10,000annual income (less than $3,000;$3,000-$5,000; $5,000-$9,999) but essentiallythe same at income levels of $10,000 and over.Although the difference is large for those withfamily incomes exceeding $15,000, the Negrosample is small, and consequently this estimateis unreliable. Negro girls, in the age range 12-17years, were slightly more mature skeIetally thanwhite girls across all three broad income groups(under $5,000; $5,000-$9,999; $10,000 and

24

+lo — BOYS +1o

g

$

0~

uCl<A +5 — +5

$

:

3z

,.,.:..,

$ ....,

b ‘~<:..:.,.

,:.?.E

ho o

i rz

:

$Lessthan $5,Q20 $5,000.$e,999 $10,000 or mare

-5 — -5

~ whk8,&ll years ~ whke,12-17Years ~ Nqro,6.11 wars ~ NW0,12-17YW3

Fimsre 14. Difference between actual and exuected mean skelatal acre (hand-wrist) for white and Negro boys and girls 6-17 years ofchronological age by annual family in~ome: United States, 1963-1970 -

over). The opposite was true in both of theextreme groups (under $3,000 and $15,000 ormore), but the small sample sizes reduce the reli-abilityy of these findings.

When the effect of differences in the chrono-logical age distribution between the two largestracial groups within income level groups isremoved, Negro boys 12-17 years of age are lessmature than expected skeletally and Negro girlsmore mature than expected in this respect acrossincome levels, although the deviations from theexpected are not large enough to be statisticallysignificant (figure 14).

Parental Education

The association between skeletal maturityand parental education among white and Negroyouths–both boys and girls–is even less clearthan that with family income (table 7). Thoseyouths whose first parent (the father if he wasstill present in the household) had completed 13years or more of formal schooling were veryslightly more advanced skeletally than those in

the same race-sex group with lesser parental edu-cation. This differential was slightly more evi-dent among boys than among girls. The differ-ences noted are much too small to be statisti-cally significant.

BONE-SPECIFIC SKELETALAGE FINDINGS

In the Greulich-Pyle method of assessment,the skeletal maturity of the hand-wrist assignedto an individual youth is based usually on theaverage of the ages assigned those of the youth’s31 hand-wrist bones that are radio-opaque butnot classified as adult. While some investigatorsuse the median and others assign an age to thewhole area without recording separate skeIetalages, the common practice of using the averagehas been followed in this report as in the pre-vious ones.l’s Although, in general, there isgood concordance among the bone-specificskeletal ages for an individual, the differencesare real and may be important.

25

The order of onset of ossification and therates of maturation of individual bones vary con-siderably among individual children and youths.It is probable that there are similar individualdifferences in the order of epiphyseal fusion, butfew findings have been reported. As a result ofthese variations, there are differences betweenthe skeletal ages assigned to individual bones in asingle radiograph. For youths in the age range ofconcern in this study, 12-17 years, nearly all the31 hand-wrist bones have become radio-opaque,but their maturation is incomplete. There areonly 2 hand-wrist bones in which the onset ofossification is normally delayed until age 12years or later–these are the adductor and flexorsesamoids in boys and the flexor sesarnoids ingirls. “

Several factors may be responsible for thedifferences that occur commonly among theskeletal ages assigned to individual bones withina single hand-wrist radiograph. The selection ofstandards by Greulich and Pylel 0 may havebeen imperfect. That is, bones each assigned thesame skeletal age in a standard might, in fact,individually differ in actual skeletal age. Thiswould not explain the largely random nature ofthe variations noted. Errors occur during theassessment of radiographs. These might be sys-tematic; for example, an assessor or group ofassessors might systematically assess a particularbone higher than the real level. The variationsdue to the assessors might, of course, be ran-dom, in which case, when the direction of theerrors are taken into account they would bal-ance each other when group data are considered,but they could cause or increase the variationamong bone-specific skeletal ages in a single radi-ograph. Reported data indicate that the compar-ability and replicability of bone-specific skeletalages are lower for the cm-pals than for the otherhand-wrist bones.Es ~E6 This could increase thevariability of the skeletal ages recorded for thesebones.

Differences in skeletal maturity levels amongthe bones of a single hand-wrist might resultfrom variability within individuals that is ran-dom in a population. Thus it is possible thatwhile the population means for all bones couldbe at the same level of maturity in children of aparticular age, there could still be variations in

leveI within individual children. Alternatively,when differences are noted among the skeletalages assigned to a radiograph, they could reflectreal genetically or environmentally determinedpopulation differences. That is, a particular boneor group of bones may systematically be lessmature or more mature than the other hand-wrist bones in a defined population.

Race

For each of the 31 hand-wrist bones themean skeletal age of white boys exceeds that forNegro boys age 12-17 years in the United States.The racial differences in the mean values are,almost without exception, small enough to bewithin the 95-percent confidence limits for esti-mates in this study. This pattern of white boysbeing more skeletally mature than Negro boysfor each bone is generally consistent at eachsingle year of age, except at age 13 years where30 of the 31 bones (all but the capitate) aremore skeletally mature in Negro than in whiteboys. Minor exceptions at other individual agesare detailed in table 9—the pisiform at age 17,the adductor sesarnoid at ages 12 and 17, theflexor sesamoid at ages 14 and 17, and middlephalanx IV at age 17.

In contrast to the findings among boysdivided on the basis of race, Negro girls of 12-17years generalIy are more advanced skeletally foreach individual bone than are white girls. Meanskeletal ages for Negro girIs slightly exceed thosefor white girls age 12-17 years in 25 of the 31hand-wrist bones, the exceptions being the capi-tate, trapezoid, metacarpal V, pisiform, and dis-tal phalanges IV and V. Across the age range inthe present study the pattern of racial differ-ences in bone-specific skeletal maturity amonggirls is nearly as consistent as that in boys, butthe reverse in direction, and the exceptionamong girls occurs at age 14 years. At each yearof chronological age except 14 years, the meanskeletal age for 20 or more of the 31 bones inNegro girls exceeds that in white girls. At age 14years, white girls are more advanced skeletallythan Negro girls are for 27 of the 31 hand-wristbones.

Previous studies. –There are few reports withwhich the present findings can be compared. In

26

the national survey of children (Cycle 11),3 itwas shown that, within a sex, there are statisti-cally significant differences between whites andNegroes (Negroes more mature) in the skeletalages assigned to the radius, ulna, carpak, andmetacarpal in each sex, and to distal phalangesIII-V in boys. In the national survey data for age12-17 years, the sex differences (femaIe equiva-lent ages for the girls) were small,l as they hadbeen during the 6-1 l-year period in the earliernational survey.2

Ma.Iina and his group86~53 reported Tanner-Whitehouse skeletal age scores for individualbones in a group of white and Negro Philadel-phia youths age 12 and 13 years. These bone-specific scores cannot be converted to skeletalages, but they can be used to compare thematuration levels in white and Negro youths ofthe same sex. In the boys, most bones weremore mature in Negro than in white youths atboth 12 and 13 years, but the reverse was notedfor the scaphoid, trapezium, trapezoid, meta-carpal I, proximal phalanx V, and distal pha-langes III and V. Without exception, all thehand-wrist bones tended to be more advanced inNegro girls than in white girls at both 12 and 13years. However, in each sex almost all the meandi f f ere rices between matching bone-specificscores in these two racial groups were small.

Geographic Region

There is no consistent pattern of regionaldifferences in the levels of skeletal maturityamong the 31 hand-wrist bones (table 10).Among boys the most frequent regional patternsin mean bone-specific skeletal ages were eitherslightly higher mean levels in the South andlower levels in the Northeast than elsewhere (12of the 31 bones) or slightly higher levels in theWest and lower levels in the Midwest than else-where (8 of the 31 bones). For girls the twomore frequent patterns were slightly highermean values for those in the Northeast andlower values in the West than elsewhere (14 ofthe 31 bones); and slightly higher mean values inthe Northeast ‘and lower in the Midwest thanelsewhere (9 of the 31 bones). Within bones,there is no consistency between the sexes inthese small regional differences.

Family Income

There is a clear lack of any strong relation-ship between skeletal age (hand-wrist) of youthsand family income in the levels of skeletalmaturity for the 31 individual bones (table 11).Among boys age 12-17 years, the highest meanskeletal ages for 20 of the 31 bones were amongthose boys in the highest annual income levelfamilies ($10,000 or more). However, the lowestmean wdues for these bones were as nearly com-mon among boys in the lowest annual incomebracket of under $5,000 (12 bones) as amongthe middle income group of $5,000-$9,999 (17bones).

Similarly, among girls age 12-17 years, thehighest mean values for 27 of the 31 hand-wristbones were found among those in the bracket of$10,000 and over but the lowest mean skeletalages were much more likely to occur among girlsin the middle income group (21 of the 31 bones)than in the lower income level (5 of the 31bones).

Range of Bone-SpecificSkeletal Ages

Commonly, and indeed almost universally,there are differences among the maturity levelsof the hand-wrist bones within a single radio-graph.57 If this were not the case the rangewould, of course, be equal to zero. While it hasbeen claimed that these ranges are greater inchildren who are skeletally retarded,58 curiouslythere have been few studies of the ranges and,until recently,1 ~Z reference data were not avail-able.

It has been claimedsSJ59 that a wide rangeof bone-specific skeletal ages within a hand-wristreduces the reliabilityy of assessments. This doesoccur when overall assessments are made, butthere has been some doubt as to whether thisfactor still operates when bone-specific assess-ments are made.60 This variation among skeletalages of hand-wrist bones gives rise to problemsof interpretation. Using the atlas method ofGreulich and Pyle, the same mean skeletal agemay be assigned to two hand-wrist radiographs,although in one the carpals may be more maturethan the other bones are and in the second radi-ograph the carpals may be less mature than the

27

other bones are. In fact, there is always uncer-tainty about the skeletal age equivalents of allradiographs in which unusual patterns of skeletalmaturity levels are present due to the lack ofadequate standardizing samples with the samepatterns.61

Many earlier workers have claimed that ill-ness or malnutrition has differential effects onthe ages of onset of ossification or rates of latermaturation among individual bones.10 Y6* ‘T 0 Ifthis were established, and if there were no“catchup” maturation, the range of bone-specific skeletal ages within a hand-wrist radio-graph would be a sensitive indicator of past envi-ronmental effects.

Findings from the present national surveywith respect to the consistency and variability ofthe range of bone-specific skeletal ages, withinindividual radiographs, have been analyzedacross racial, re~onal, and family income levelsubgroups among youths in the United States ofchronological age 12-17 years. As do the com-parable findings among U.S. children age 6-11years from the preceding national survey,3 theseprovide reference data that can be used to assessthe possible effects of such factors as illness ormalnutrition on skeletal maturation. Mediansand quartile points in the distributions of therange of bone-specific skeletal ages within indi-vidual hand-wrists by race, geographic region,and family income are included in tables 12-14.

Race. –Among white youths age 12-17 years,the median range in these bone-specific skeletalages decreases with advancing chronological agesomewhat more rapidly in girls than boys (table12). The median values for boys exceed thosefor girls at each chronological age. Toward theend of the range, this would be expected,because girls characteristically reach adult levelsearlier than do boys and as a consequence therewould be fewer bones in the girls to which skele-tal ages could be assigned. For white boys themedian range decreases from 15.9 months at age12 years to 4.9 months at age 17 years; while forwhite girls the decrease is from 14.4 months atage 12 years to 1.7 months at age 17 years.Although the median values are higher for theboys, the variability in these skeletal age ranges,as measured by the difference between the 25thand 75th percentiles in their distributions, isgenerally less among white boys than among

white girls. Exceptions occur at age 12, wherethe values are nearly identical (8. 1 months forwhite boys and 8.0 months for white girls) andat age 16, where values for white girls are theless variable (1 1.2 months for white boys and9.6 months for white girls). The younger whiteboys age 12-15 years show less variability (.P7~ -Pz ~ of 8-9 months) than the older white boys of16 and 17 years (P75 - P25 of about 11months); among white girls the variabilityyincreases from a minimum at age 12 (P7 ~ - P2 ~of 8 months) to a maximum at age 15 years(P75 - P25 of 15.4 months).

As among white youths, the median rangesof bone-specific skeletal ages within individualhand-wrists for Negro youths decrease withadvancing chronological age and somewhat morerapidIy in Negro girls than boys. The medianvalues for Negro boys exceed those for Negrogirls throughout the age range 12-17 years. ForNegro boys the median range of bone-specificskeletal ages within the hand-wrist decreasesfrom 15.0 months at age 12 years to 8.4 monthsat age 17 years; among Negro girls the decreaseis from medians of about 12 months at 12 and13 years (1 1.6 months and 12.5 months, respec-tively) to 2.7 months at age 17 years. The varia-bility in these skeletal age ranges, as measuredby the difference between the 25th and 75thpercentile in their distributions, is less amongNegro boys than among girls at age 12-16 yearsand is somewhat less among younger (age 12-15years) than among older (age 16-17 years) Negroboys. The pattern of variability across chrono-logical age among Negro girls is slightly less con-sistent than that for Negro boys.

There is no consistent racial differencebetween white and Negro youths in these rangesof skeletal maturity. Median ranges for whiteand Negro boys differ by only negligibleamounts (1 month or less except at age 17years) across the age range and not consistentlyin one direction; among girls the median valuesfor white girls at ages 12-15 years are slightlygreater than those for Negro girls. When variabil-ity is judged from the difference between 75thand 25th percentiles, both white and Negro boysat ages 12-15 years are less variable in skeletalmaturity than their older counterparts; the pat-tern of variability is less consistent among bothwhite and Negro girls. There are no marked dif-

28

fcrences in the variability of these ranges whenyouths are separated on the basis of race withina sex.

Geographic region. –No significant patternof geographical regional differences is evident inthe range of bone-specific skeletal ages withinthe hand-wrists of youths in the United States(table 13). Among boys, the geographic regionalmedian values in these ranges decrease consist-ently with advancing chronological age from15-16 months at age 12 years to 4-6 months atage 17; among girls the medians decrease from13-15 months at 12 years to 1-4 months at age17 years. Although the differences betweenregions are generally small, there is a slight tend-ency for the median ranges to be larger in theWest for boys and in the Northeast for oldergirls. Furthermore, there is a slight tendency forthe variability of these ranges in the girls to begreater in the Northeast; but a similar tendencyis not apparent in the data for the boys.

Socioeconomic factors. –Possible socioeco-nomic influences on the range of bone-specificskeletal ages within individuals in the youths’age range were analyzed in relation to familyincome. There is no consistent pattern ofincome-level differences in the ranges of bone-specific skeletal ages for boys or girls age 12-17years (table 14). Within each of three broadincome groups, there is a fairly consistent andsimilar pattern of decrease in these ranges withadvancing age. Among boys, the decrease in themedian values is from 15-16 months at age 12years to 4-7 months at age 17 years; among girlsthe decrease is from 13-15 months at age 12 to1-5 months at age 17 years. Among girls, but notboys, the median ranges tend to be slightlylarger for those with family incomes of$5,000-$9,999 per year than for the groups witheither larger or smaller incomes. This resultwould be puzzling were it not that the differ-ences between these income groups of girls intheir median ranges of bone-specific skeletal ageswere generally small.

ONSET OF OSSIFICATION FINDINGS

During the age range of youths, 12-17 years,ossification usually begins in two hand-wrist

bones–the adductor and flexor sesamoids inboys and the flexor sesamoid in girls.

Race

Among white boys in the United States, themedian age of onset of ossification in the adduc-tor sesamoid is 12.4 years, somewhat earIierthan that for Negro boys (12.7 years). Themedian age of onset for the flexor sesamoid ismore than a year Iater but shows about the sameracial difference, and in the same direction, 14.2years in white boys and 14.5 years in Negroboys (tabIe 15). The median age of onset of ossi-fication for the flexor sesamoid in girls is about1 year earlier than in boys and is about the samein white as Negro girls–13.O years and 13.1years, respectively.

Geographic Region

Across all four regions into which the UnitedStates was divided for the purposes of this sur-vey, the median age of onset of ossification forthe adductor sesarnoid in boys is 12.5 years. Forthe flexor sesarnoid the median age of onset inboys ranges from a low of 13.3 years in theMidwest to 14.4 years in the South and West.Among girls there is essentially no geographicregional difference in the median age of onset ofossification—1 3.1 years in the Northeast and13.0 years in each of the other three regions.

Family Income

Among boys (table 15), the median age ofonset of ossification for the adductor sesamoidis negligibly lower for those in the middleincome bracket of $5,000-$9,999 per year (12.4years) than in either the lower or higher incomelevel groups (12.5 years for both those with lessthan $5,000 and those with $10,000 or morefamily incomes). The onset of ossification forthe flexor sesamoid is delayed in boys from thefamily income group of under $5,000 per year(14.4 years); it is about 1 year later than themedian age for the onset of ossification of thisbone in boys in the yearly income levels of$5,000 or more. The median age of onset for theflexor sesamoid in girls shows a consistent butnegligible association with family income. Themedian age for those girls in families with less

29

than $5,000 annual income is 13.1 years and is12.9 years at the income level of $10,000 ormore per year.

Previous studies. –Reported modal ages forthe onset of ossification in the adductor sesa-moid in United States boys and the flexor sesa-moid in both boys and girls are included in tableH. The data in this table are based on two typesof modal ages: the median or mean age at onsetof ossification and the age when the center wasossified in 50 percent of the youths. The latterestimate was obtained after plotting the per-cents, at successive chronological ages, on proba-bility paper. The youths included in these sam-ples were predominantly of northwestern Euro-pean ancestry and of middle, or slightly abovemiddle, socioeconomic status.

The report of Harding71 was based onmixed longitudinal data from white youths inBoston born between 1930 and 1939 and ex-amined near each birthday. The sample sizevaried from 40 to 60 at each age in each sex.

The data of Greulich and Pylel 0 and Pyle etaLTs were obtained from serial radiographs, byinterpolation, on the thesis that onset of ossifi-cation occurred between the age at which thecenter was first visible radiographically and theage at which the last radiograph was taken inwhich the center was not visible radiograph-ically. The interpolated ages were not necessarilymidway between the ages at which these twoannual radiographs were taken. However, it isreasonable to assume that the recorded ageswere systematically 0.5 year earlier than wouldhave been recorded had these authors appliedthe more familiar method of recording the age at

which the center was first observed. Conse-quently, to make these findings more compar-able, in methodology, with those reported byothers, 0.5 year has been added to each modalage reported by Greulich and Pylel 0 and Pyle etal.Ts before it was included in table H. Greulichand Pylel 0 analyzed data from serial radio-graphs of 100 boys and 100 girls in the BrushFoundation study. These were white youths ofupper socioeconomic class living in Cleveland,Ohio, who had been born between 1917 and1930. Data from the serial study at the Depart-ment of Maternal and Child Health at HarvardUniversity were reported by Pyle et al.T3 Theseyouths (16 boys, 14 girls with relevant data)were white and middle-class socioeconomically,and were living in or near Boston, Massachusetts,having been born between 1930 and 1939. Theyouths whose data were reported by Pyle etaL73 were included also in the group studied byHarding.71

The data of Buehl and Pyle64 were obtainedfrom a subset of Brush Foundation youths (30boys). It is not clear whether these authors inter-

polated ages at ossification in the manner ofGreulich and Pylel 0 and Pyle et al. ;T3 conse-quently the reported ages have not been ad-justed.

Mixed longitudinal data derived from middlesocioeconomic class white youths in southwest-ern Ohio who were born between 1929 and1960 were reported by Garn et a.1.7z Theseyouths were radiographed within 1 month ofeach birthday and half-birthday. The sample sizewas about 180 for each sex in each 6-monthinterval.

Table H. Modal ages (years) for onset of ossification in selected bones in U,S. white youths

Bone and sex

BOYS

Adductor sesamoid ..... .. ... . ... ... ... .. ... .. ... .. . .... ... .. .. . ... .. ... .. ... .... .. .. ... ... .. .. ...Flexor sesamoid .. ... .. ... ... .. .. .. .... .. ... .. ... ... .. . ... ... .. ... ... .... . .. ... .... . ... ... ... ... ... .

Girls

Adductor sesamoid .. .. .. .. .. .. .. .. .. .... .. .. . .. .... . ... ... .. ... .. .. ... ... .. ... .. ... ... .. .. ... ... .Flexor sesamoid .. ... ... .. .. .... . ... ... ... . ... .. . .. .. ... .. .. ... .... .. .. ... .. .... .. .. ... .. ... ... ... ..

12.16413.510

10.5’3411.01’J

Modal age from previous studies

12.673

10.772

12.771

10.810

12.872

11.073

13.210

11.274

UnitedStates,

1966-1970

12.514.2

10.713.0

30

Hansman74 studied about 50 white boysand 50 white girls of middle socioeconomicstatus who were enrolled in the program of theChild Research Council, Denver, Colorado.These youths were born between 1915 and19540

There is very close agreement between theages reported by Pyle et aL,73 Harding,7 I andGarn et aL7z for the onset of ossification of theadductor sesamoid in boys. It is surprising, how-ever, that both the earliest and the latest ageshave been reported from the Brush Founda-tion.64 )73 In part, this may be methodological.As noted earlier, Buehl and Pyle may have inter-polated, in which case 0.5 year should be addedto the ages reported by them. The median agefor white boys in the national survey is at aboutthe midpoint of the range of modal ages re-ported by others. In both boys and girls, theflexor sesamoid began to ossify just slightly laterin the national survey youths than in the groupof youths studied by Greulich and Pyle.1 OTheseauthors have provided the only other set of dataon age of onset of ossification for the flexorsesamoid of youths in the United States.

In reviewing data for youths of Europeanancestry living outside the United States,emphasis will be placed on those countries fromwhich large numbers of immigrants have cometo the United States. Joseph’5 reported dataconcerning the onset of ossification in theadductor sesamoid for English youths living inLondon, but the sample size and the method ofreporting do not allow useful comparisonsbetween his conclusions and those of the presentnational survey. Semp&76 reported median agesfor the onset of ossification of the adductor ses-amoid and flexor sesarnoid in French youths (91boys, 89 girls) generally of middle socioeco-nomic status living in Paris (table J). Theseyouths were born in 1953 and radiographedclose to birthdays and half-birthdays. Rudzin-ski’ 7 reported modal ages for the onset of ossifi-cation of the adductor and flexor sesamoidsbased on mixed longitudhml data from 6-monthradiographs of 91 Polish boys in Warsaw. Theseages for youths in Paris or Warsaw are slightlylater than the estimates for U.S. white youths inthe present national survey (table J), with theexception of the flexor sesarnoid in girls. It is

Table J. Modal ages (years) for onset of ossification in youths ofEuropean ancestry living in Europa

I Modal age

Bone and sex

I 197076I I

Boys

Adductor sesamoid . ... .. .. ... ... .. ... . .... .. .. .... I 13.0 13.0Flexor sesamoid .. .. .. .... .. .. ... . .. .. .. .. ... .... . .. 14.0 13.5

Girls I IFlexor sesamoid ... .. ... .. ... .. .. ... ... .. .. ... .. ... . 1 12.01 ---

NOTE: Semp&French youths in Paris; Rudzinski–Polishyouths in Warsaw.

stressed, however, that all these differences aresmall.

Comparisons can be made between reportedmodal ages for the onset of ossification in somehand-wrist centers in Negro youths living in theUnited States and Negro youths living in Africa.The differences are not easily interpreted be-cause it is impossible to identify groups of Negroyouths in the United States or Africa thatbelong to the same relatively homogeneousgenetic pool. The data considered for Negroyouths in Africa relate to the part of Africafrom which large numbers of slaves were trans-ported to the United States,7s ~’g but, almostcertainly, the present U.S. Negro population isunrepresentative of the original slaves and theslaves were unrepresentative of the African pop-ulations from which they were taken.

Michaut-Barthod80 reported data from 628radiographs of Ovoloff youths of low socioeco-nomic status living in Dakar (Senegal). Most ofthese youths were radiographed three times nearbirthdays or half-birthdays. About 40 radio-graphs were available for each sex at each6-month interval. Although all the youths weremore than 11 years of age at the time of theirfirst radiograph, the data are useful for compara-tive purposes. Masse and Hunts 1 reported cross-sectional data from children of Ovoloff ethnicorigin living in Dakar. The sample included 45 to95 children of each sex in both age groups. Thedata of Michaut-Barthod80 and Masse andHunt8 I make it clear that the onset of ossifica-tion tends to occur considerably earlier in U.S.

31

Negro girls than in African Negro girls theystudied, but the corresponding differences aresmaller for boys.

Sutow42 reported data from normal Japa-nese youths of all socioeconomic levels in Hiro-shima. The sample size for each sex varied from67 to 104 for each year of age. The ages at onsetof ossification that he reported (boys: pisiform12.3 years, adductor sesamoid, 14.0; girls:adductor sesamoid, 11.8 years) are considerablylater than those found in Cycles 112 and 1111ofthe Health Examination Survey. As pointed outearlier in this report, it is likely that the currentages of onset of ossification in Japanese youthsare much closer to those of youths in the UnitedStates.

EPIPHYSEAL FUSION

The national survey data were used to esti-mate median ages at epiphyseal fusion by inter-polating between prevalence data for annual age

groups. This allowed reasonably accurate esti-mates for all relevant bones except the radius ineach sex and the ulna in the boys. The order ofmedian ages was closely similar in each sex andin both white and Negro youths. Fusion tends tooccur earlier in white boys than in Negro boys(table 16). For about half the bones (metacarpalI, proximal phalanges I-V, and middle phalangesII-V) these bone-specific differences are statisti-cally significant at the 5-percent level. Thebone-specific racial differences in median ages atepiphyseal fusion are less consistent in the girls.About half these median ages are earlier in whitegirls than in Negro girls; and nearly half areearlier in Negro than in white girls. Fusionoccurs significantly (5-percent level) earlier inwhite girls than in Negro girls for metacarpal I,proximal phalanges I-V, and middle phalangesII-V. An opposite tendency, also significant atthe 5-percent level, is present, however, for theulna; metacarpal II-V; and distal pha.IangesI, II,and IV.

Table K. Modal aoesfor e~i~hyseal fusion in the hand-wrist of U.S. white youths

Hand-wrist bone

Radius .......................................................................................Ulna .......................... .............................. ..................................

Metacarpal I ..............................................................................Metacarpal II .............................................................................Metacarpal 111............................................................................Metacarpal lV ............................................................................Metacarpal V .............................................................................

Proximal phalanx I ....... .............................................................Proximal phalanx 11...................................................................Proximal phalanx III .................................................................Proximal phalanx IV ...... ...........................................................Proximal phalanx V ...................................................................

Middle phalanx II ......................................................................Middle phalanx Ill .................... .................................................Middle phalanx lV .....................................................................Middle phalanx V ......................................................................

Distal phalanx I ................................................ .........................Distal phalanx 11........................................................................Distal phalanx III ....................................................................!.Distal phalanx IV ......................................................................Distal phalanx V ........................................................................

Boys

18.07417.874

16.374’8216.4,s2 16.57416.4,a2 16.574‘16.474Va216.574’s2

16.2,73*74 16.3a216.3,a2 16.47416.2,73 16.374*S216.2,a2 16.57416.274’82

16.474*a216.4,8216.57416.474*8216.3,74 16.4s2

15.7,= 15.97415.7,7315.8,74 16.0a216.074*8215.8,74 16.0a215.9,74 16.0a2

Modal age

15.87415.974

14.1 ‘4$214.5,74 14.6s214.5,74 14.6s214.4,7414.68214,4,7415.082

14.2,7414.3,73 14.4a214.274Sa214.2,74 14.5s2~4.274,a2

14.274*82

14.274S8214.4,74 14.5*214.3,741 4.5=’14.2,7414.382

13.5,a2 13.674‘12.5,64 ~3.6,74’a2 [email protected],52

. . .

. . .

15.816.516.616.616.6

16.315.916.116.115.8

16.116.316.316.3

15.715.815.815.615.7

. . .16.2

13.814.814.814.915.0

14.014.014.114,114,0

134914.114,114.0

13.513.513,513.413.4

32

Previous Studies

Data from other studies of white youthsliving in the United States are included in tableK. There are no previously reported data forNegro youths in the United States. Hansman74reported data on Denver, Colorado, youths ofabove average socioeconomic status who weremdiographed at 6-month intervals. These youths(about 30 of each sex) were born between 1915and 1941.

Data from a small group (IV= about 12 foreach bone in each sex) of Boston youths havebeen reported by Pyle et a.1.73 These middleclass youths who were born between 1930 and1939 were radiographed annually. In interpret-ing these data, it is important to recall that therelatively late-maturing males are underrepre-sented because the study was discontinuedbefore all had matured.

Buehl and Pyle64 reported data from 30boys and 30 girk of upper socioeconomic statusenrolled in The Brush Foundation Study, Cleve-land, Ohio, who were examined serially. Find-ings from 107 youths in southwestern Ohio whowere slightly above average socioeconomicallyhavt been reported by Garn et al.g Z In all thesestudies, as in the national survey, epiphysealfusion was considered to be present when theepiphyseal cartilage had been completely re-placed, even if a radio-opaque line persisted atthe junction.

In general, the national survey estimates areclose to those reported for these smaller, lessrepresentative groups; the match is particularlyclose for girls. The median ages for boys fromthe national survey are earlier than those in theprevious reports for metacarpal I, proximalphalanges II and V, middle phalanx II, and distalphalanges IV and V. In girls, the national surveyages are earlier than those reported previouslyfor middle phalanges III and IV and later formetacarpal IV.

There are few sets of satisfactory datareported for youths living abroad. Ages at whichcpiphyseal fusion occurred, using cross-sectionaldata from 1,613 Japanese children and adoles-cents, have been reported by Russell et al.s 3Although the subjects had been in utero in Hiro-shima or Nagasaki at the time of the atomicbombing, there was no evidence that the age of

Table L. Reported ages of ep:

Hand-wrist bone

Radius ... ... ... . .. .. . ... ... .. .. ... ... ... . .Ulna .. ... .. .. ... ... ... .. .. ... .. .. .... . ... ..

Metacarpal I ... .. .. .. .. .. .. .. .. .. .... ..Metacarpal II .... .. ... .. ... ... ... .. . ...Metacarpal Ill .... ... .. .. ... .. .... . ... .Metacarpal IV ... ... .. ... ... .. .. .. .. ...Metacarpal V . .. .. ... .. ... .. .. .. .. .. .. .

Proximal phalanx 1..... .. ... .. ... ..Proximal phalanx I l . ... . .. .... .. .. .Proximal phalanx Ill .... .. ... . ... .Proximal phalanx IV ... .. ... ... . ..Proximal phalanx V .... ... .. .. ... ..

MiddIe phalanx I I ... ... . .. .... .. ... .

Middle phalanx I I I ... .. ... .. .. .. ....Middle phalanx IV . .... .. . .... .. ... .Middle phalanx V .... ... .. .. . .. .. ...

Distal phalanx 1. .... .. ... .. ... .. .. ...

Distal phalanx I l .... . ... .. .. .. . ... .. .Distal phalanx Ill . .. ... . .. ... .. .. .. .

Distal phalanx IV .... .. ... . .. .. .. .. .Distal phalanx V ... .. .. .... . ... .. .. ..

lvseal fusion in

Russall et al.,1973’33

Boys

18.7518.25

16.2516.7516.7517.017.0

16.7516.7516.7516.75

16.75

16.7517.017.0

16.75

16.016.2516.25

16.516.5

Girls

17.7517.25

14.7515.5015.2515.515.75

15.2515.015.015.25

15.0

15.2515.515.5

15.0

14.514.514.5

14.7514.5

]anese youths

Sutow19534$

Boys

18.8IB.7

. . .---..-..----

. . .

. . .---

.-.

---. . ...-

. . .

---

16.3----..---

17.517.3

..--..----..---

----....-

. . .

. . .-..---

. . .

. . .

14.5. . .. . .. . .

closure was related to the estimated radiationexposure dose. The ages reported by Russell etal.s 3 indicate that fusion occurred about 7

months later than in U.S. youths (table L).These findings are in general agreement withthose of other workers who have studied groupsof Japanese youths.4 Z74s *84

Median ages at fusion in the third proximal,middle, and distal phalanges of Danish boys arevery similar to those estimated from the UnitedStates National Survey.85

DISCUSSION

There is no doubt that youths of differentracial groups vary in body size and in levels ofskeletal maturation and sexual maturity at cor-responding chronological ages.86 ‘g 1 The factorsthat control the rate of skeletal maturation mustact by influencing the formation or resorptionof bone. The possible factors are related togenes, nutrition, illness, and climate, inter alia,but few studies have been designed so as to sep-

33

arate the possible effects of these factors. Conse-quently, knowledge is almost entirely lackingconcerning the effects of relatively precise envi-ronmental factors (e.g., protein intake, tempera-ture), on rates of skeletal maturation in youthsor of specific groups of genes (e.g., autosomal,sex-linked).

This discussion will relate to the factors con-sidered in this report (race, geographic region,size and type of community, family income,parental education) that could have been associ-ated with real population differences in skeletalmaturity levels. The findings from the presentsurvey will be discussed in relation to the find-ings from the corresponding study of childrenage 6-11 yearss and in relation to reports basedon findings from smalIer less representativegroups. In interpreting these findings, it shouldbe recalled that the national surveys are the onlysource for national estimates of skeletal matur-ity levels. The sarnpling technique employedensured that a truly representative sample waschosen for each survey. Of the children chosen,96 percent were examined; the correspondingfigure for the youths is 90 percent. Conse-quently, these national surveys can provide rea-sonably reliable estimates for the entire U.S.population of children and youths.

Race

It is difficult to interpret racizd comparisonsbecause, almost always, the groups compareddiffer not only genetically but in environmentalfactors, particularly in nutrition and the inci-dence of disease. The importance of genetic fac-tors is clear from studies of the timing and pat-tern of onset of ossification and the occurrenceof skeIetal variants (e.g., pseudoepiphyses)in pairs or triads of individual sharing similarenvironments but different proportions ofgenes.65)92-111 These studies indicate that

the extent of the differences within pairs ortriads are approximately inversely related to thepercentage of genes shared in common.

Skeletal age (hand-wrist). –The two nationalsurveys show that Negro boys tend to be moremature skeletally than white boys at 6-9, 11,and 13 years, but the reverse is true at the otherages. White girIs, however, are less mature skele-tally than Negro girls throughout the whole age

range except at age 16-17 years. There are noconsistent white-Negro differences in the varia-bility of skeletal age. These findings indicatepossible changes with age in racial differences(white-Negro) relating to skeletal maturation inboys and girls, but the patterns vary between thetwo sexes. Soon after birth, centers of ossifica-tion are more numerous in newly born Negroesthan in whites; this is true for Negroes living inAfrica as well as for those living in the UnitedStates. This acceleration in Negroes occursdespite their generally less favorable socioeco-nomic circumstances.1 11’1 ‘ 5 This advancementof Negroes in onset of ossification has beenreported up to about 7 years of age.1 1G~11THowever, as noted earlier in the national sur-veys, Negro youths were more advanced in skele-tal maturation than white youths only until age13 years (and then not at all ages) in boys and

‘ until 16-17 years in girls. Age-related patterns ofracial differences in skeletal maturity have beennoted by Lee et all 18 These workers reportedthat Chinese children in Hong Kong wereadvanced in onset of ossification over U.S. chil-dren when early-appearing hand-wrist centerswere considered, but an opposite tendency waspresent for late-appearing centers.

In the national survey data there are onlyslight differences between the mean values forskeletal age in Negro and white youths withineach sex. The small size of these differences andtheir inconsistency across age and sex are inagreement with reports by Toddz4 andMalinas ~‘s 5 and MaIina et al.~ G that white-Negro differences are inconsequential during theage range 12-17 years. The substantial accelera-tion of skeletal maturation in U.S. Negroes com-pared with those in Jamaica or Dakars TIS8 pre-sumably reflects environmental effects.

Previous studies of groups of white U.S.boys10,16-19,21-23 are not in complete agree-ment with the national survey findings that themean skeletal ages of U.S. white boys are consid-erably less than the mean chronological ages at9-12 years. While Flory,l G Todd,l 8 andMareshz 2 reported low mean skeletal ages dur-ing this age range, the patterns of change withage in their data differed from those in thenatiomd sample. It must be stressed that theseearlier studies were of less representative groupsof youths in the United States, and most of the

34

studies were not based on bone-specific skeletalages. A further factor to be considered is thelevel of reliability of assessments of skeletalmaturity.

The natiomd survey data for white girls(female equivalent values) are generally similarto those for boys with two exceptions: the retar-dation of the mean skeletal ages from 9 to 12years is less marked, and there is a marked andrapid retardation after 15 years. The data ofFloryl 6 indicate an even greater skeletal retarda-tion of girls at 9-12 years, but the early litera-ture contains no hint of the change in reIativeleveI after 15 years that is so marked in thenational survey data. As discussed earlier,l thisis almost certainly due to the fact that all thenational survey radiographs were assessed, with-out identification by sex, against a single set ofmale standards. Later the values for girls weretransformed to female equivalent values using aset of sex-associated differences in skeletal ageprovided by Dr. S. Idell Pyle. These sex differ-ences were derived by Dr. Pyle after a painstak-ing stud y of radiographs.g However, to take theextreme example, the means of the skeletal agesassigned to boys and girls age 17 years on themale standards differed by ordy 5.9 months,whereas the difference of 22 months as reportedby Pyle et al.g was used in the transformation.The actual sex difference on the male standardswas greater than reported in the HES Standardgat the earlier ages. Its marked reduction at laterages was due only slightly to the exclusion ofgirls in whom all the hand-wrist bones hadbecome adult.

The previous literature for U.S. youthswould lead one to expect that epiphyseal fusionwould be complete throughout the hand-wrist ofa typicaI girl age 17.5 years, but that fusionwould not have occurred at the distal ends ofthe radius and ulna in a typical boy of the sameage.73 !74,82 ALso, these earlier studies Iead tothe expectation that in a majority of the girlsage 17.5 years it would be impossible to assessthe hand-wrist because all the bones of this areawould be adult. In the national survey data thisoccurred in 22 percent of the girls. If a skeletalage of 19.1 years were assi~ed to each of thesegirls (19. 1 years is the highest maximum value

for any bone on the male standards) this wouldhave very little effect on the sex-associated dif-

ferences in skeletal maturity, as calculated pre-viously. This matter is discussed more fully inthe earlier report.]

There is no evidence of a secular trend inskeletal maturation rate when the data for whiteU.S. children and youths are compared withreported findings from earlier studies. This istrue whether the comparison is with the sets ofdata in figures 1-410>1 G-19,21,22 or with data

reported still earlier from New England childrenand youths, 24 percent of whom were of Italianancestry.1 1g,1 ZO

It is not easy to interpret the apparentabsence of secular trends when data from thenationaI surveys are compared with data fromless representative groups-sampling variationsmay mask real differences or alternatively anydifferences found may be due to sampling varia-tions. These methodological problems can beovercome only by repeated national surveys, butit is interesting to note some findings from long-term serial studies of unrepresentative groups inthe United States.

In the group of southwestern Ohio childrenand youths studied at the Fels Research Insti-tute, rezd secular trends are not apparent over aperiod of 36 years, when skeletaI age is regressedagainst year of birth (table M).1 z 1 Similarly, inthe same group, the mean relative differences forRWT (Roche, Wainer, and Thissen) skeletal agesbetween parent-offspring pairs, within sex, aresmall and inconsistent in direction (table N).RWT skeletal ages are obtained from the knee,but there is no reason to believe that this area isany less representative of the whole skeletonthan is the hand-wrist.61 These findings showthat little if any secular trend has occurred dur-ing recent decades in a group of children and

Table M. Correlation coefficients between skeletal age(Greulich-Pyle) and year of birth in the Fels LongitudinalStudy (Roche, unpublished data)

Boys GirlsChronological age

N r N r

3 years ................................... 112 -0.016 118 +0.1 876 years................................... 120 -0.088 105 +0.1629 years ... .. ... .. .. ... .. ... ... .. ... . ... .. . 91 +0.179 82 +0.185

12 years .. .. . .... .. .. .... .. ... . ... .. ... ... . 73 –0.01 1 73 +0.705

NOTES: None of these coefficients is significant at the5-percent leveL

N = number of subjects; r = simple correlation coefficient.

36

Table N. Mean relative differences between parant-offspringpairs in skeletal age (RWT, knee in years)

Chronological age

6 years ..... .. .. .. ... .... .7 years ... ... .. ... .. ... .. .8 years .... ... .. ... .. ... ..9 years ... .. .. .. .. ... .. .. .

10 years .... ... .. ... .. ... ..11 years .. . ... .. .... .. .. .. .12 years .. .... . .. .. ... ... ..13 years ... ... .. ... ... .. .. .14 years .... .. . .. ... .. .. . ..15 years ... ... . .... .. .. .. ..16 years .... .. ... ... .. ... . .

Difference

Father-son—N

—

25242325211714

898

8—

Mean

-.33-.15+.40+.29+.1 2+.16+.24+.04

+.17

-.93-.02

Sx

1.161.361.141.321.451.321.891.360.75

0.590.51

Motherdaughter—N—

3335322919

20211717

1910— I

Mean Sx

-.16 1.17+.21 1.10+.23 1.40+.08 1.35-.35 1.28-.95 1.52-.14 1.00-.15 0.98-.32 1.15

-.62 1.71-.57 1.48

NOTE: + = rmrent more mature; N = number; s. =standard deviation.

.

youths of middle socioeconomic status wheneffects of sampling variability are largely re-moved. These findings are in close agreementwith those of Mareshl 2 Z who reported datafrom a middIe socioeconomic group in Denver,Colorado. Taken together, these studies suggestthat secular trends in skeletal maturation ratesare absent or very slight in white U.S. childrenand youths of middle socioeconomic status. Ofcourse, due to the method of group selection,these findings cannot be extended to all socio-economic levels and geographic regions as thenational survey data can for youths in theUnited States.

The tentative conclusion that secularchanges in the rates of skeletal maturation mayno longer be occurring in the U.S. populationshouId be considered in reIation to secularchanges in body size. After a close analysis ofdata recorded in national probability samplesbetween 1962 and 1974,90 S1239124 it was con-cluded there was no evidence of a secular trendin either stature or weight during this periodexcept for a slight change at the lower percent-iles. Thus the data for body size are in agree-ment with the tentative conclusion that has beenreached in regard to skeletal maturation.

Variability. –The national survey findingsconcerning possible white-Negro differences inthe variability of skeletal age are inconsistentsuggesting that , if such differences do occur,they must be small. In each of these racial

groups skeletaI age was more variable for theboys than for the girIs. This is in agreement withearIier reports.1 6J19Y38Y39Y5z Presumably it isdue, at least in part, to truncation of the distri-butions for girls as they approach the upperlimit of the skeIetal maturity scaIe.

Bone-specific skeletal ages. –The nationalsurvey data show that, among boys 12-17 years,the mean skeletal age of each hand-wrist bone ismore advanced in the whites than in the Ne-groes, although the individual differences are notlarge enough to be statistically significant. There !is an opposite tendency among girls but this alsois not statistically significant. The directions ofthese differences within each sex, at 12-13 years,match those reported by Malina et a.1.36 and byMalina.53 As would be expected from the find-ings for mean skeletal ages, the white-Negro dif-ferences in bone-specific skeletal ages are, how-ever, in the reverse direction to those found inthe national survey of children.3 In the earliersurvey, most of the individual hand-wrist boneswere less mature in the whites than in the Ne-groes.

In the national survey data, there are no con-sistent white-Negro differences in the meanranges of bone-specific skeletal ages or in thevariability of these ranges within individualhand-wrist radiographs. In both Negro and whitegroups, the means of the bone-specific skeletalages are less variable in boys than girls, but therange of bone-specific skeletal ages is greater inboys than in girIs.

Onset of ossification. –Only for the adductorand flexor sesamoids in boys and the flexor sesa-moid in girls do the modal ages of onset of ossi-fication occur during the age range of the pres-ent survey (12-1 7 years). White boys are veryslightly advanced over Negro boys in medianages for the onset of ossification in these bones(0.3 year); the corresponding difference for theflexor sesamoid in girls is trivial (0.1 year).These findings are consistent with the small, sta-

tistically nonsignificant white-Negro differences

in mean skeletal age and bone-specific skeletalages. The national survey data are close to thosereported for other groups of white youths in theUnited States except for the flexor sesamoid inboys. The only previous estimate for thisbonel 0 is considerably earlier. There are no pre-

36

vious estimates for Negro youths in the UnitedStates.

Epiphyseal fusion. –The national survey dataallow estimates for the median ages at epiphy-seal fusion for all hand-wrist bones that developepiphyses except the radius in both boys andgirls and the ulna in boys only. In the latterbones, the median ages are too late for them tobe estimated accurately from the present data.There is no evidence of a racial difference in thesequence of fusion, but fusion tends to occurearlier in white boys than in Negro boys. Thiswould be expected from the racial differences inskeletal maturity levels for boys. Both in girlsand in boys there is a consistent pattern of sta-tistically significant differences in ages at epi-physeal fusion between white and Negro youths(metacarpal I, proximal phalanges I-V, andmiddle phalanges II-V); these ages are earlier inwhites than in Negroes. There is a significantracial difference in the opposite direction in girlsfor the ulna, rnetacarpals II-V, and distal pha-langes I, II, and IV. This is in agreement with thefinding that white girls are less advanced skele-tally than Negro girls at 12-15 years althoughthe reverse is true at 16-17 years. The estimatedages at fusion for white boys and girls are verysimilar to those reported by others for smallergroups of U.S. youths;G4~T3Y74Y8z there are nocomparable data for Negroes in the UnitedStates.

Geographic Region

Very few studies of regional factors allowthe separation of genetic and specific environ-mental effects. Regional differences, within theUnited States, in the incidence of illness, basedon the same regions considered here, will be pro-vided in later NCHS reports. Regional differ-ences in nutritional status have been reportedfrom the Ten-State Nutritional Survey,l zs andanthropometric differences have been reportedin a previous NCHS report.124

An earlier report3 provides estimates ofregional differences in the skeletal ages of U.S.children 6-11 years. After removal of the effectsof age differences and varying racial distribu-tions among regions, there was a tendency forU.S. children in the Northeast and MidwestRegions to be slightly advanced in skeletal

maturity compared with those in the otherregions. However, most of these regional differ-ences relating to children age 6-11 years couldhave been due to chance.

The data for U.S. youths (boys and girls)from the present survey reveal only small re-gional differences after age-related and race-related effects are removed. Those in the Southare slightly more advanced skeletally and thosein the Midwest slightly less advanced than thosein the Northeast and West, but these differenceswere not statistically significant. Sampling varia-bility could have been responsible for the varia-tion between this pattern for youths and thatreported previously for children.s If the skeletalmaturity of U.S. youths indeed differs by geo-graphic region, this was obscured by the largeheterogeneous regions into which the UnitedStates was divided when the national survey datawere analyzed.

If real differences between geographicregions had been found, it could have been pos-tulated that climatic factors were responsible.Despite suggestions, there is no convincing evi-dence that tropical climates retard skeletalmaturation,l z6~1z T although it does appear thatwarm climates retard age of menarche. 1z 8 Thereare severe difficulties in interpreting the re-ported data because there has not been controlof many confounding variables in the studydesign or the statistical analysis. While heat pro-motes calcification experimentally,l z9~130 thisis doubtfully relevant. Studies of experimentalanimals in extreme environmental tempera-tures 18*13 l‘133 suggest that heat acceleratesskeletal maturation, but large ambient tempera-ture differences between the control and experi-mental groups are needed to p~oduce this effect.

If -significant differences had been foundbetween the skeletal maturity of groups ofyouths separated by geographic region, it wouldhave been difficult to associate these differenceswith climate. The fact that significant differ-ences were not found may reflect the diversityof these large regions and, perhaps, migrationbetween them. If the aim had been to demon-strate the existence of regional differences, amore appropriate sampling (e.g., of those livingat high altitudes, in the desert, or in the arcticregion) would have been employed. Howeverinteresting, such a study would be less important

37

in relation to public health within the UnitedStates than the present estimates forverykirgegroups.

Bone-specific skeletal ages. –The differencesbetween the mean bone-specific skeletal ages forgroups separated on the basis of geographicregion are inconsistent. This would be expectedfrom the lack of statistically significant differ-ences between the mean skeletal ages for groupsof youths in the four large geographic regions ofthe United States. The mixed pattern of ad-vancement and retardation among the bone-specific skeletal ages for each region is inconsist-ent for the two sexes. This indicates a lack ofmajor differences among the regions in their gen-eral levels of factors, as an example, nutrition,known to affect the rate of skeletal maturation.Similarly, there are only small differences amongthe geographic regions in the median ranges ofbone-specific skeletal ages within single radio-graphs. There is, however, a slight tendency forthe median ranges to be larger for boys in theWest and for older girls in the Northeast.

Onset of ossification. –There were almost noregional differences in the mean ages of onset ofossification for either the adductor sesarnoid orthe flexor sesamoid except that the flexor sesa-moid in boys ossified somewhat earlier in theMidwest.

Urban-Rural

There are no consistent urban-rural differ-ences in mean skeletal ages either for youths inthe present national survey or for children in theprevious survey.3 However, among youths butnot among children, there is a slight tendencyfor skeletal maturation to be advanced in thoseliving in large urban areas (population exceeding3 million). Presumably, the absence of real dif-ferences between urban and rural areas reflectsthe heterogeneous nature of the environmentwithin these groupings and the lack of majorurban-rural environmental differences in theUnited States, as in the case in Australia.l34This situation differs sharpIy from that in someother countries where there are major socioeco-nomic differences between urban and rural areasand associated differences in rates of skeletalmaturation and physical growth.l 35-14 Z

Socioeconomic Factors

Skeletal maturation. –The importance ofsocioeconomic factors in controlling the rate ofskeletal maturation, as distinct from age at onsetof ossification, has been stressed by severalworkers.l 8Y1ss ~14s -14 f’ Particularly importantdata have been reported by Low et al.s g whorecorded Greulich-Pyle skeletal ages for a largegroup of Hong Kong youths separated into high(IV = 3,659), middle (N= 5,227), and low(N= 5,591) socioeconomic groups (table O).This grouping was made using a combination ofparents’ education, parents’ occupation, totalfamily income, and housing.8 T Skeletal maturitylevel is associated positively with socioeconomicstatus in these data, but the mean differences aresmall despite the very wide ranges of socioeco-nomic status among the groups compared. Thesecomparatively smaIl differences are in agreementwith the observations of Grande CoVi&n and RofCarballo.l 4 G

Kopczyfiska3 z reported data from upperand lower socioeconomic class Polish youths(total N= 3,988) that show a significant associa-tion in the expected direction between socioeco-nomic status and the level of skeletal maturity.Because her data were analyzed on the basis ofthe percentages of subgroups in whom thechronological age exceeded the skeletal age,

Table O. Mean skaletal ages for southarn Chinese youths inHong Kong at various socioeconomic levels (Low et al.,1964)39


Boys

12.0 years .. ... .. ... .. .. ... .. .. ... .. .. ... ... .. .... .. ..13.0 years .. .. .... ...o.. .. ... .. .. .. .... .. .. ... .. ... .. .14.0 years ... .. ... .. ... .. ... .. .. ... . .... .. .. .. ... ... ..

15.0 years ..... .. .. .. .... .. . ... .. ... .. .. ... ... .. ... .. .

16.0 years ... .. .... .. .. .. .. ... ... .. .. ... .. .. ... . .. ... .17.0 years .. .... .. .. .. .. .. .... .. .. .. ... . .. .... .. .. ....

Girls

12.0 years .... .. ... ... .. .. .. .. .. ... ... .. .. .. ... ... .. ..13.0 years ... . ... ... . .. .. .. ... . ... .. .. .. ... ... .... .. ..14.0 years ... ... .. .. .. ... ... .. .. .. ... .. ... ... .. ... ... .

15.0 years ... .. .. .. .. .... . ... .. . .. .. .. .. .... ... . .... ..

16.0 years .... .. .. .... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

17.0 years ... .. ... ... .. .. .. .. .. .... . ... .. ... .... ... . ..

Socioeconomic status

High Middle Low

Mean skeletal age

11.512.813,9

15,316.617.7

12.313.614.6

15.5

16.317.0

11.112.513.8

15.1

16.417.6

12.113.314.5

15.4

16.317.0

11.112.513.9

15.016.217.3

11.813.014.2

15.3

16.217.0

38

direct comparisons cannot be made betweenthese data and those of Low et aL39 with regardto the magnitude of socioeconomic effects.

Neyzi et aL147 using data from 2,000 urbanTurkish youths of moderately different socio-economic levels found only slight associationswith skeletal maturity levels. The differenceswere significant only when extreme socioeco-nomic groups were compared and, even then,only in the girls. These relatively small or absentsocioeconomic effects on the rate of skeletalmaturation in youths support the contention ofAchesonl48 that the slowing of skeletal matura-tion with an adverse environment has beendemonstrated with certainty only in the prepu-bertal period.

The differences among socioeconomicgroups reported by Low et al.39 for Chineseyouths were slightly greater in girls than in boysup to age 15 years. Later, there was a slight sexdifference in the reverse direction that may havebeen due, in part, to some of the girls reachingthe upper limit of the skeletal maturity scale.This greater effect in girls is in agreement withthe findings of Neyzi et aL147 In Polish youths,however, the apparent effect of socioeconomicstatus on skeletal maturity level is greater inboys than girls.3z)149

Deschamps and Benchemsil 50 reportedfindings from 4,526 French children and youthsexamined at ages from 6 to 18 years. The hand-wrist skeletal ages (Greulich-Pyle) of these chil-dren were significantly related to the occupationof the father (especially in boys), the level ofeducation of the mother (girls only), the qualityof housing (both sexes), and the number of chil-dren in the family; Their data were not analyzedwithin age groups: but the authors report thatthe differences in skeletal maturity levels withenvironmental factors were more marked in ado-lescents, which is in conflict with the report ofFrisancho et al.l51 Although many of the dif-ferences reported by Deschamps and Ben-c hernsils O were statistically significant, themean differences were rather small (3-6 monthsof skeletal age), which is in general agreementwith other reports from Belgiuml52‘ *s 3 andFrance.1s 4

These variations between studies in sex dif-ferences could reflect variations among races inthe sensitivity of skeletal maturation to socio-

economic influences, or differences among racesbetween the care of boys and girls classified asbeing at the same socioeconomic level. Thesereports draw attention to the slender and incon-sistent evidence on which claims are made thatskeletal maturation is less affected by environ-mental factors in girls than in boys.

Andersen, in her analysis of data fromCopenhagen children,z 8 reported a markedassociation between skeletal maturity level andthe father’s occupation and a lesser associationwith family income. There were no real differ-ences in skeletal maturity levels in relation toemployment of the mothers, but crowding ofapartments seems to be associated with skeletalretardation in lower socioeconomic groups.

When such skeletal retardation occurs, it isprobable that adverse environmental circum-stances do not affect all bones equally. Differ-ential effects have been described within thehand-wrist only. 1ss If they occur throughoutthe skeleton, they could lead to differences inbody proportions between upper and lowersocioeconomic groups. That such differences inproportions are affected by environmentzd influ-ences may be inferred from data relating to theratio

sitting heightstature

in Japanese youths, American-born Japaneseyouths, and American children.A 0 This inferenceis supported also by the marked secular trend inthis ratio. Similarly, a secular trend toward amore linear build has been noted in Yugoslaviawith improved socioeconomic conditions. 1s 6

In the present national survey, socioeco-nomic status was categorized by family income(within wide groupings) and by years of parentzdeducation. In the survey data, mean skeletal ageis not related consistently to family income.Although there is a slight tendency for it to beslightly more advanced in those with familyincomes exceeding $10,000 per year, the lowestincome group (less than $3,000 per year) werenot the least advanced in either sex. This lack ofa clear-cut relationship is not due to a confound-ing effect of race. Within racial groups, there isno consistent relationship between familyincome and skeletal maturity. However, withinfamily income groups, white boys tend to be

39

more mature skeletally than Negro boys forthose in families of moderate or lower incomelevels under $10,000 while white girls tend to beless mature in this respect than Negro girls irre-spective of family income level. Similarly, thereare no statistically significant differences inskeletal maturity between groups separatedaccording to the length of parental education.

There is also no strong interrelationshipbetween bone-specific skeletal ages and familyincome. While more advanced ages tend to occurin the upper famiIy income groups, the lowestages are almost equally distributed between themiddle and lower family income groups. The dif-ferences among the ranges of bone-specific skele-tal ages, within single radiographs, for groups ofyouths separated by family income are verysmall and the pattern of differences is inconsist-ent.

Onset of ossification. –The modal ages re-ported from previous studies concerning theonset of ossification for youths in the UnitedStates of northwestern European ancestry werederived from middle or slightly superior socio-economic groups (table B). Those studied byHarding71 were from average middle class fami-lies. Findings from youths described as beingfrom a good class of English-speaking peoplewere reported by Baldwin et all57 The data ofHansman74 were derived from upper-middlesocioeconomic class youths studied by the ChildResearch Council, Denver.ls 8 The youthsstudied by Floryl 6 were also above average ineconomic and in social status. The youths fromwhom Garn et al.7 z obtained data were gen-erally of upper-middle socioeconomic status, butnot quite as high as the sample of Hansman.7 *

It is difficult to interpret the variationsamong ages at the onset of ossification reportedby these workers in relation to socioeconomicstatus. Youths in the groups studied by Hans-man74 and Floryl 6 appear to have been ofslightly higher socioeconomic status than youthsin the groups studied by others. If such a differ-ence in socioeconomic status were present, it isnot reflected in the data for age at onset of ossi-fication (table H).

The failure of these studies to show socio-economic effects on age at onset of ossificationmay be due to the fact that they were not de-

signed for this purpose or, perhaps, such effects

are slight. It has been suggested that socioeco-nomic status has more effect on the onset ofossification in infancy and childhood than inadolescence.1 51

The median ages at onset of ossification,estimated from the national survey data foryouths, for the adductor sesarnoid in boys andthe flexor sesamoid in girls are not related con-sistently to family income. However, the onsetof ossification of the flexor sesamoid in boys ismarkedly delayed in the lowest family incomegroup. In generzd, these findings are in agree-ment with earlier reports that the onset of ossifi-cation is rather insensitive to environmentaleffects, but it is not completely insensitive. Thisis clear from the rather large differences betweencorresponding ages for Negroes in the UnitedStates and Africa.80 ~81

Epiphyseal fusion. –There are no previousstudies of the influence of socioeconomic fac-tors on age at epiphyseal fusion, however, it canbe concluded from the data of Low et aL39 thatsuch differences are probably small. Reporteddata concerning the age at which growth instature ceases are not helpful because elongationof the trunk continues after the cessation ofelongation in the Iimbs.1 59 Furthermore, serialdata from individuals studied until at least age25 years are not available for low socioeconomicgroups. Such data are necessary, however, todetermine when growth in stature has ceased inan individual.160

The national survey data show the absenceof a close interrelationship betweensocioeconomic status judged by broad groupingsof either family income or parental educationand various aspects of skeletal maturation (meanskeletal age, bone-specific skeletal ages and theirranges, onset of ossification, and epiphysealfusion). It is important, however, to stress thatthese findings relate to only a limited range ofsocioeconomic status; real effects may be pres-ent at lower levels than those studied. If sucheffects were present, they might reflect theinfluence of differences in illness experience anddiet. The literature concerning these factors willbe reviewed briefly.

Illness

Onset of ossification.-The influence of illnesson age at onset of ossification in children has

40

been reviewed recently.2 There have not beencorresponding reports for youths, perhaps be-cause so few centers begin to ossify between 12and 17 years in the areas of the skeleton that areusually radiographed for skeletal age assess-ments. The evidence indicates that the usual ill-nesses of childhood have little or no effect, butwhen effects occur they may differ amongbones. There is little doubt that very severe ill-nesses retard the onset of ossification in chil-dren, but all the previous reports for childrenhave come from either the Brush FoundationStudy or the Fels Research Institute. Thesereports relate to “normal” volunteers in whomsevere illnesses were uncommon. Additionally,the timing of radiographic examinations wasscheduled according to chronological age; it wasnot planned to maximize the possibility ofdemonstrating the effects of illnesses. In a sched-ule designed for this purpose, examinationswould be made before, during, and after eachillness.

It has been claimed that unusual orders ofonset of ossification are due to illnesses near thetime of ossification of particular centers; as ares u 1t ossification of these centers is de-Iayed.1O)18 $6z ~6A The report of Garn and Roh-marm161 f or children, and that of Hansman andMaresh66 for children and youths do not sup-port this view. If illnesses had such an effect,they would be associated with increases in theranges of bone-specific skeletal ages within radi-ographs. This subject has not been studied ade-quately; reports based on very few individualshave led to conflicting conclusions,l A8,] 6z,]63In a large-scale study, it has been shown that themedian order of onset of ossification in thehand-wrist is the same in Guatemala boys as inboys in southwestern Ohio and that the variabil-ity of sequence was similar in both groups,although illnesses were much more common inthe Guatemalans.164

Skeletal maturation. –In youths, skeletalmaturation is retarded by severe illnesses but itaccelerates during the catchup growth that mayfollow the illness. 16s The nature of the illnessmay be important. Bashe and Ratnerl 66,167assessed 1,054 hand-wrist radiographs of chil-dren and youths hospitalized because of tuber-culosis. About half of these patients were Negroand all were of low socioeconomic status, de-

spite which many were skeletally advanced. Inthese patients there was no apparent relationshipbetween skeletal maturity level, or the ranges ofbone-specific skeletal ages within individuals,and either the severity or the duration of thedisease.

Epiphyseal fusion. –Reports are not availableconcerning the influence of generalized illnesseson age at epiphyseal fusion.

Diet

There is no doubt that undernutrition re-tards the onset of ossification and skeletal ma-turation and, presumably, it retards epiphysea.1fusion. Many studies are difficult to interpretbecause of confounding variables and the lack ofreliable information concerning specific dietaryfactors. Commonly of course, undernutrition isassociated with a high incidence of disease, poorhousing, and racial differences.

Onset of ossification. –There is convincingevidence that malnutrition retards the onset ofossification, but during adolescence these effectstend to be smalll G1 or absent.168 Dreizen etal.,16 9 using serial radiographs, studied theonset of ossification in 541 undernourishedwhite urban children and youths in AIabama.There was a marked delay that tended to begreater in girls than in boys (table P).

In generaI, in the data of Dreizen et al,l 69the standard deviation Ievels for ages at onset ofossification in the late ossifying bones (adductorand flexor sesarnoids) were higher than those forbones that ossify during childhood. This is incontrast to the claim of Frisancho et all51

Skeleta[ maturation. –Undernutrition retardsskeIetaI maturation and dietary supplementationaccelerates it in youths.lAs~lA6SlGG>170-17GThese effects are less marked in girls than inboys.15 5 Skeletal maturation is slow also inyouths with inflammatory bowel disease;1 76

Table P. Retardation (years) in age of onset of ossification ofhand-wrist centers in malnourished white youths (data ofDreizen et al.. 1958)169

Hand-wrist bones I BOYS I Girls

Adductor sesamoid .... .. ... . ... ... .. .. .. .. .... .. ... . .. .. .. .. .. .

I-0.1

I-0.7

Flexor sesamoid .. .. .. . ... .. ... .. ... .. . .... .. .. ... ... ... .. . ... ... . -0.7 –1.7

41

this may be a result of the associated malnutri-tion.

Few have studied the effects of specific nu-trients, but an increased rate of maturation inskeletally retarded youths occurs after the miIkintake is increased.1 71 J177 Mack and Ur-bachl72 showed that restriction of calories, inassociation with a protein intake at the recom-mended level, resulted in retardation of skeletalmaturation. Others consider that the level ofprotein intake may be a more important factorthan the level of caloric intakes g Both workersmay be reporting correctly; the difference be-tween the reports could reflect differencesbetween the groups studied in their deficienciesof specific nutrients or groups of nutrients; thebulk of the evidence shows that skeletal matura-t io n is retarded in undernourished youthswhether the main lack is in calories or pro-teins.151j173~178

Malnutrition apparently has a differentialretarding effect across bones. Dreizen et al. I r greported that the carpals and the bones of thefifth finger were more retarded than otherhand-wrist bones in undernourished Alabamachildren and youths of British ancestry. Anattempt was not made, however, to estabIishwhether there were corresponding real differ-ences in bone-specific skeletal ages in well-nour-ished children within the same populationgroup. It is well to be cautious when assessingtheir conclusions. The differences reported byDreizen et all79 could reflect variations be-tween these workers and Greulich and Pyle inthe ways in which bone-specific skeletal ageswere assessed.

Mass6 and Hunt81 have claimed that skeletalretardation due to malnutrition is less marked inthe carpa.ls than in the short bones of the hand-wrist. Whichever of these conflicting views iscorrect, acceptance of Todd’s attitudels thatone should use the most advanced centers as aguide to actuaI maturity would lead to the em-ployment of the centers that are least sensitiveto environmental influences. This would be inap-propriate in many circumstances.

In general, overnutrition has effects in exper-imental animals that are the opposite to theeffects of undernutrition.18 O~1s I The changesin overfed animals resemble those in overweightor obese youths,ls z‘1 g 1 although a significant

association between overnutrition and acceler-ated skeletal maturation was not found byHortling et alls 3 except in obese adolescentswho were also short.

Within age groups, the level of skeletalmaturity is correlated positively with weight andsubcutaneous fat thickness,ls Y1s G>1g z but thisrelationship is not close. The acceleration ofskeletal maturation is more marked in those whohave been obese for a long timel g0 or in whomlean body mass is increased.193 It has beenreported that the effect of ovemutrition on therate of skeletaI maturation is equal in bothsex e S;l 9 * others consider the effect moremarked in girls than boys.1 90 Furthermore, ithas been claimed that the acceleration of skele-tal maturation in obese youths is more markedin the Iate than in the early ossifying carpals.1 g 1Probably, however, this reflects only the greatervariabilityy of the ages at onset of ossification inthe carpals that are Iate to ossify.

Epiphyseal fusion. –Data from malnourishedchildren and youths who received a milk supple-ment have been reported by Spies et all Tq Withsupplementation, skeletal maturation was accel-erated in the children, but in the youths therewas no reduction in the delay of epiphysealfusion.14 5 It has been claimed that malnutritiondelays epiphyseal fusion to similar extents ineach sex and in each bone. 14s It is difficult todetermine the accuracy of this claim becausesatisfactory reference data for the sequence ofepiphyseal fusion and the distribution of ages atepiphyseal fusion have not been available.

SUMMARY

In this report, data for the skeletal maturityof the right hand-wrist in noninstitutiona.lizedyouths age 12-17 years are analyzed and de-scribed in respect to race, geographic region, sizeand type of community, family income, andparental education. The original data wereobtained from radiographs taken during theHealth Examination Survey of 1966-1970. Forthis survey, a representative sample of 7,514youths was chosen from the entire U.S. popula-tion within the age range 12-17 years. Examina-tions were made of 90 percent (6,768) of theyouths who had been chosen.

42

The radiographs were assessed, bone bybone, by specially trained medical students whodld not know either the age or the sex of anyyouth whose radiograph was assessed. Thisremoved several sources of bias. The assessmentswere all made against male standards, thus pro-viding a unique opportunity to establish the trueextent of the sex-associated differences in ratesof skeletal maturation. Later, the ages assignedto the girls were adjusted to female equivalentvalues, using a set of sex-associated differencesin skeletal maturity reported by Pyle et zd.g Inthis summary, reference will be made not onlyto the data from the present survey but also tothe data from the corresponding survey of chil-dren 6-11 years.z 33

Negro boys tend to be more mature skele-tally than white boys at 6-9, 11, and 13 years,but not at other ages within the range 6-17years. Negro girls, however, are more matureskeletally than white girls at all ages except 8,16, and 17 years. It must be stressed that thedifferences between the means are small, whichis in agreement with several earlier reports. Themean skeletal ages for both white and Negroboys are markedly less than the mean chrono-logical ages at 9-12 years, showing, as reportedearlier, that the Greulich-Pyle Atlas standardsduring this age range are set much too high forthe total U.S. population. There is a similar pat-tern in the girls, but the differences between themean skeletal and mean chronological ages aresmaller. While the levels of skeletal maturity forwhites in the United States are close to thosereported for northern European children, levelsof skeletal maturity for Negroes in the UnitedStates are substantially accelerated comparedwith groups of Negroes in Africa and Jamaica.

In the girls, whether white or Negro, theskeletal ages (female equivalent values) are mark-edly retarded (less than chronological age) after15 years. Almost certainly, this is due to the useof inappropriate sex differences to transform tofemale equivalent values the skeletal ages ob-tained against the male standards. A survey ofearlier literature had led to the expectation thatalmost all hand-wrist bones would be adult in atypical girl at 17.5 years; actually, only 22 per-cent of the girls age 17.0 -17.9 years had all theirhand-wrist bones mature. Even if the maximumvalue of the male set of standards were assigned

to each excluded girl, this would have influencedonly slightly the mean skeletal ages (femaleequivalent values) for the girls. The large retarda-tion of female equivalent values at older ages is,almost certainly, due largely to the inaccuracyof the sex-associated differences used to obtainthe female equivalent values.

There is no evidence that the bones of U.S.children and youths are now maturing morerapidly than in recent decades. There is evidencethat any such changes have been absent or slightin white U.S. children of middle socioeconomicstatus; conclusions for the total populationawait the analysis of data from repeated nationalsurveys.

Mean skeletal ages tend to be more advancedin Negro boys than in white boys at most agesup to 10 years but not, in general, later. Themean skeletal ages tend to be more advanced inNegro than in white girls at all ages except 8, 16,and 17 years. The mean hand-wrist skeletal agesare more variable in boys than in girls, but thereare no consistent differences in variabilitybetween white and Negro youths. There are sta-tistically significant differences in bone-specificskeletal ages between white and Negro groups ofboys when each bone is considered separately,but there is a general tendency for each bone tobe more mature in white than Negro boys from12 to 17 years. The slight tendencies noted arein the reverse direction to those reported earlierfrom the national survey of children. Similarly,the white-Negro differences in both the meanranges of bone-specific skeletal ages within singlehand-wrists and in the variability of these rangesare too small to be statistically significant. In thegirls, there is an opposite tendency that is notsignificant for the majority of the individualbones to be more mature in Negro than in whitegirls from 7 to 17 years.

The white-Negro differences in both themean ranges of bone-specific skeletal ages withinsingle hand-wrists and in the variability of theseranges are too small to be statistically signifi-cant. Also, there are no consistent white-Negrodifferences in the ages at onset of ossification ofthe adductor and flexor sesamoids.

Epiphyseal fusion, judged from the medianages, occurs in the same sequence in both whiteand Negro youths. Fusion occurs significantlyearlier in white than in Negro youths of both

43

sexes in metacarpal I, proximal phalanges I-V,and middle phalanges II-V. Among girls there arealso significant racial differences in the oppositedirection for the ulna; metacarpal II-V; and dis-tal phalanges I, II, and IV.

After adjusting for effects associated withchronological age and racial distribution, U.S.children age 6-11 years in the Northeast andMidwest Regions tend to be somewhat advancedskeletally, although much of the observed differ-ence could have been due to chance.3 Amongyouths in the United States age 12-17 years, thedifferences in skeletal maturity between regionsare small also. Youths in the South tend to bemore advanced and those in the Midwest lessadvanced than youths in the other two regions.

There are inconsistencies between variationsby geographic region in mean skeletal ages andthose in age at onset of ossification. In part, thismay reflect the few hand-wrist bones in whichossification had not occurred by age 12 years. Ifthere are real regional differences in the UnitedStates, it is probable that they occur only amongmuch smaller regions than those analyzed. Wheneach region is considered as a whole, there areonly minor differences among the four largeheterogeneous regions into which the UnitedStates was divided for the purpose of this na-tional survey.

The earlier literature indicates that socioeco-nomic factors exert a definite influence on the

rate of skeleta.1maturation, but these effects aresmalI unless extreme groups are compared. Thepresent national survey data are consistent withthese earlier findings.

Within both white and Negro groups ofyouths, mean skeletal age is not related consist-ently to family income. Nevertheless, except atthe extremes of family income where the esti-mates are less reliable because of small samplesize, white boys tend to be more mature skele-ta.lly than Negro boys and white girls less maturein this respect than Negro girls within cor-responding family income groups. In the na-tional survey data, there is a similar pattern ofinconsistent differences associated with familyincome for bone-specific skeletal ages, the rangeof these ages within individual radiographs, andonset of ossification. However, the data relatingto onset of ossification are somewhat more con-sistent, especially in girls, but the differencesbetween family income groups are small.

In the present report, numerous referenceshave been made to earlier studies of smaller andless representative groups of youths in this coun-try and abroad. These other studies have pro-vided much important information, but the datafrom the present national survey together withthose from the previous survey of youthsl $3provide, for the first time, estimates that areapplicable to the total U.S. population in the agerange 6-17 years.

000

44

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49

162pyle, so I., M~n, A. W., Dreizen, S., Kelly, H. J.,Macy, I. G., and Spies, T. D.: A substitute for skeletalage (Todd) for clinical use: the red graph method. ].Pediatr. 32:125-136, 1948.163Hoerr, N. L., Pyle, S. I., and Francis, C. C.: Radio-

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fication of the bones of the wrist in institutional chil-dren. II. Effect of cod liver oil supplement. Amer. j. Dis.Child. 58:295-319, 1939.17 lMacNair, V. and Roberts, L. J.: Effect of a milk

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Effect of improved care on the predicted adult height ofundernourished children. Nature 194:735-736, 1962.

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Animals. Butterworth Scientific Publications. London.Butterworth & Co., Ltd., 1954.181 Dickerson, J. W. T., and Widdowson, E. M.: Chemi-

cal changes in skeletal muscle during development.Biochem. J. 74:247, 1960.182 Bruch, H.: Obesity in childhood: Physical growth

and development of obese children. Am. J. Dis. Child.58:457-484, 1939.183Hortling, H., de la Chapelle, A., Frisk, M., and

Widholm, O.: The syndromes of obesity and of delayedgrowth in adolescence. Acts Med. Stand. (Suppl.) 412:109-122, 1964.184Mossberg, H.-O.: The X-ray appearance of the knee

joint in obese overgrown children. A eta Paediat. Stand.38:509-516, 1949.185 Garn, S. M., and Haskell, J. A.: Fat and growth

during childhood. Science 130:1711, 1959.186Garn, S. M., and Haskell, J. A.: Fat thickness and

developmental status in childhood and adolescence. Am.J. Dis. Child. 99:746-751,1960.187 Fry, P. C.: A comparative study of “obese” children

selected’ on the basis of fat pads. J. Clin. Nutr.1:453-467, 1953.188 Peckos, P. S.: Caloric intake in relation to physique

in children. Science 117:631, 1953.189Melhnau, W. J., Bongiovanni, A. M., and Hope, J.

W.: The diagnostic usefulness of skeletal maturation inan endocrine clinic. Pediatrics 23:530-544, 1959.190 Frisk, M., Widholm, O., Tenhunen, T., and Hortling,

H.: Overweight in adolescents–a complex problem. Ann.Paediatr. Fenn. “12:234-245, 1966.191Markuske, H.: Rontgenologische Untersuchungen

der Handwnrzelknocken adipbser Kinder. Z. Kinder-heilk. 106:225-234, 1969.192Maresh, M. M.: Changes in tissue widths during

growth, Roentgenographic measurements of bone, mus-cle, and fat widths from infancy through adolescence.Am. J. Dis Child. 3:142-155, 1966.193 Forbes, G. B.: Growth of the lean body mass during

childhood and adolescence. J. Pediatr. 64:822-827,1964.194National Center for Health Statistics: Quality con-

trol in a National Health Survey, by W. L. Schaibee.Vital and Health Statistics. Series 2-No. 44. DHEW Pub.No. (HRA) 74-1023. Health Resources Administration.Washington. U.S. Government Printing Office, Feb.1972.

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195Nation~ Center for Health Statistics: Sample designand estimation procedures for a national Health Exami-nation Survey of children, by E. E. Bryant, J. T. Baird,and H, W. Miller. Vital and Health StatzWcs. Series 2-No.43. DHEW Pub. No. (HSM) 72-1005. Health Servicesand Mental Health Administration. Washington. U.S.Government Printing Office, Aug. 1971.196Moore, W. M,: Compwability in skeletal maturation

research. Am. ]. l%ys. Anthropol. 35:411-415, 1971.197Anderson, M., Hwang, S.-C., and Green, W. T.:

Growth of the normal trunk in boys and girls during thesecond decade of life, related to age, matmity, and ossi-fication of the iliac epiphyses. J. Bone Joint Surg.47A:1554-1564, 1965.~98Gray, S. W., and Lamons, F. P.: Skeletal develop-

ment and tooth eruption in Atlanta children. Am. J.Orthod. 45:272-277,1959.lg9Acheson, R, M.. Fowler, G., Fry, E. I., Janes, M.,

Koski, K., Urbane, P., and van der Werff ten Bosch, J.J,: Studies in the reliability of assessing skeletal maturityfrom x-rays. Part 1. Greulich-Pyle Atlas. Hum. Biol.35:317-349, 1963.200 Roche, A. F. g Associations between the rates of

maturation of the bones of the hand-wrist. Am. J. Phys.Anthropol. 33:341-348,1970.

2°1 Mazess, R. B., and Cameron, J. R.: Skeletal growthin school children: maturation and bone mass. Am. J.Phys. Anthropol. 35:399407, 1971.202Ma~~d, D.: Etiution of the skeletal age method

of estimating children’s development: II. Variable errorsin the assessment of roentgenograms. Pediatrics13:165-173, 1954.2°3Anderson, M.: Growth, overgrowth, and matuxity:

observations based upon examination of serial roentgen-ograms of children with hemihypertrophy. Am. J. Phys.Anthropol. 27:246, 1967.2°4Moed, G., Wight, B. W., and Vandegrift, H. N.:

Studies of physical disability: reliability of measurementof skeletal age from hand films. Child Dev. 33:37-41,1962.2°5Johnston, F. E.: Skeletal age and its prediction in

Philadelphia childxen. Hum. Biol. 35:192-201, 1963.206 Demischj A., and Wartmann, P.: Calcification of

mandibular third molar and its relation to skeletal andchronological age in children. Child Dev. 27:459473,1956.207 Koski, K., Haataja, J.,and Lappakiinen, M.: Skeletal

development of hand and wrist in Finnish children. Am.J. Phys. Anthropol. 19:379-382,1961.

51

LIST OF DETAILED TABLES

1. Mean, standard deviation, and standard error of the mean skeletal age (hand-wrist) of youths by race, chronological age at last

birthday, and sex: United States, 1966-1970 .. ... ... .. .. ... .. ... .. ... .. .. .. . ... ... .. .. .... . ... ... .. .. .... .. .. .. . ... ... .. ... .. .. .... .. .. .... . ... .. .... .. ... . ... .. ... ....4....

2. Mean, standard deviation, and standard error of the mean skeletal age (hand-wrist) of youths by geographic region, chronolog-ical age at last birthday, and sex: United States, 1966.1970 . .... . .. ... .. .. .. . ... .. .... .. ... .. ... ... .. .. ... ... ... .. ... . .. .... . ... ... ... .. ... .. ... .. ... .. .. ..c.c..c...

3. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by geographic region, chronological

age at last birthday, and sex: United States, 1966-1970 ..... . .. ... ... .. ... ... .. ... . ... ... ... .. ... .. .. ... ... .. .. ... .. .... . ... .. .... .. ... ... .. .. .. ... .. ... .. .. .. .. ... ...

4. Mean skeletal age (hand-wrist) of youths by population size in urban areas and land use in rural areas of residence, chronolog-ical age at last birthday, and sex, with selected standard errors: Unitad States, 1966-1 970 .. ... .. .. ... ... ... ... .. ... ... ... . .. ... .. .. ... .. .. ... .. .. . .

6. Mean, standard deviation, and standard error of the mean skeletal age (hand-wrist) of youths by annual family income, chron-ological age at last birthday, and sex: United States,1966-1 970 .. ... .. ... ... .. .. .. ... .. .. ... .. .. ... .. .. ... ... .. ... .. ... .... ... .... . ... .. .. ... ... .. .. .. .. .. ... . ....

6. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by annual family income, chron-ological age at last birthday, and sex: United States, 1966.1970 ... .. .... .... . .... .. .. ... . .... .. ... . ... ... .. .. .. ... .. .... ... .. .... ... . .... . .... . ... .. . ... .. .. ... . .

7. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by education of first parent, chron-ological age of youth at last birthday, and sex: United States, 1966.1970 ....................................................................................

8. Selected percentiles in the distribution of skeletal age (hand-wrist) for youths by race, geographic region, annual family in-

come, chronological age at last birthday, and sex: United States, 1966-1970 .. .... . ... ... .. .. ... .. ... .. .. ... .. ... .... .. ... .. ... ... ... .. ... .. . ... . ... .. ... . .

9, Mean bone-specific skeletal ages for the 31 individual hand-wrist bones of white and Negro youths by chronological age inyears at last birthday and sex, with selected standard errors: IJnited States, 1966.1970 ... . ... ... ... ... ... ... ... .. .... ... .. ... .. .. .... . ... . ... .. .. ... .

10. Mean bone-specific skeletal ages for the 31 individual hand-wrist bones of youths by geographic region, chronological age inyears at last birthday, and sex, with selected standard errors: United States, 1966-1 97 O.. .. ... ... .. ... .. .. ... .... .. ... . .... .. .... . ... .. .. .. .. ... .. .. .

11. Mean bone-specific skeletal ages for selected hand-wrist bones of youths by annual family income, chronological age at last

birthday, and sex, with selected standard errors: United States, 1966-1970 . ... ... . .... . ... ... .. ... .. .. ... ... .. ... ... .. .... .. . .. ... .. ... .. . ... .. ... .. .. .. ..

12. Selected percentiles in the distribution of the individual youth’s range in bone-specific skeletal ages for the radio-opaque (notadult) bones in the hand-wrist for white and Negro youths by chronological age in years at last birthday and sex: UnitedStates, 1966-1970 .... ... .. .. .. ... ... .. .. .... .. ... . ..... . .. ... ... ... ... .. ... .. .. ... .... .. .. .. .. .. .. .. .. .... .. . ... .. ... .. ... .. .. .... .. .. .. .. ....... ................................ .........

13. Selected percentiles in the distribution of the individual youth’s range in bone-specific skeletal ages for the radioopaque (notadult) bones in the hand-wrist for youths by geographic region, chronological age in years at last birthday, and sex: United

States, 1966-1970 ... .. .. ... ... .. .. ... .. .. .. .. .. ... .. ... ... ... ... .. .... . .. ... .. .... .. .. .. .... ... .. .. ... . ... ... .. ... . .... .. .. ... .. .. ... .. ... ....... ................................ .........

14. Selected percentiles in the distribution of the individual youth’s range in bone-specific skeletal ages for the radio-opaque (notadult) bones in the hand-wrist for youths by annual family income, chronological age in years at last birthday, and sex: UnitedStates, 1966-1970 .. ... .. .... .. . .. . .... .. ... .. .. ... .. ... .. ... ... ... ... .. ... ... .. .... .... .. ... ... .. .. .... . ... .. ... .. .. ... .. .. .. ... .. ... .. .... ...... ................................ .........

15. Median (chronological) age of onset of ossification in selected hand-wrist bones for youths 12-17 years by race, region, annual

family income, and sex: IJnited States, 1966.lg71) .... . ... .. .. ... ... ... . .... .. ... .. ... ... . ... ... .. .. .. ... .. ... .. .. ... .. ... ... .. .. .... .. ... .. ... .... .. ... .. .. ... .. ... .. .. .

16. Median age in months at epiphyseal fusion for selected hand-wrist bones of white and Negro boys and girls 12-17 years ofchronological age at last birthday: United States, 1966.1970 .. .. . .... .. .. ... ... .. .. ... ... .. .. .. ... ... .. .. .. ... .. .... ... .. .. ... ... .. ... ... .. ... ... .. .. ... .. .. ... .. ..

53

54

55

66

57

58

60

61

64

70

78

86

86

87

87

88

52

Table 1. Mean, standard deviation, and standard error of the mean skeletal age (hand-wrist) of youths by race, chronological age at lastbirthdav, and sex: United States, 1966-1970

Standard of reference, sex, and chronologicalage at last birthday

Male standard

Boys:12 years ... ... ..... .. .. .... .. .. ... ... .. ... .. .. .. ... . .. .. .. .. .. .. .. .... .. ... ... .. .. .. .... ..13 years ..... .. .... .. .. .. ... ... ... .. ... ... . .. . .... ... .. .. .... .. ... .. ... ... ... .. .... .. .. .. .14 years ... .. .. .... .. .. .... ... ... .. .. .. . ... .. .. .... ... .. .. ... .. .... .. .. .... .. .. ... ... .. .. .15 years .. . ..... ... ... .. ... ... .. ... . .... .. ... ... ... .. ... .. ... ... ... .. .. .. .. .. .. .... .. .. .. .16 years .. ... ... ... ... ... . ... ... ... .. .. .... .. .. .... .. .. .. .... ... ... . ... ... ... .. .. ... ... .. .17 years ..o. ... ... ... .. .. . ... . .. ... . ... ... ... .. .. .... .. .. .. .. .. .. .. . ... .. .. .. .. .. .. .... . ..

Girls:12 years .. .. ... .. ... ... .. .... . .. ... ... .. .... .. .. .. .. .. ... ... .. .. .... .. ... .. ... ... .. ... .. ..13 years .. .... ... ... ... .. ... .. ... .. ... .. .. .. .. .. .... .. .... . ... .. .... . ... ... . .... .. ... .. ...14 years ....b.. .... .. ... ... ... . .... . .... ... .. .. .... .. .. ... ... .. .... .. ... ... .. .. .... .. .. ...15 years ... .... .. ... ... ... . .. ... ... .. ... .. .... .. ... . .... .. .... .. ... ... .. .. ... ... ... . .... ..16 years .. ..... .. ... .. ... ... .. ... ... .. .. .. .. .. .. .. .... .. .. .... .. .. .. .... .. ... .. ... ... .. ...

17 years ... .... .. ... ... .. .. .. ... ... . .... .. .. .... .. ... ... ... .. .. .... . .. .. .. .... .. .. .. .... ..

Actual Values:BOYS 12-17 years ... . ... ... ... . .... .. .... .. ... ... .. ... ... .. .. .. ... .. . .. .. .. .... .. .. ..Girls 12-17 years .. ... .. ... ... .. ... .. .... .. .... . .... .. .... .. .. .... . ... .. .... .. .. .. .. .

Expected values:Boys 12-17 years ... .. .. ... ... .. ... .. ... .. .. .. .. .. .. ... ... .... .. .. .. ... ... ... . .... .. .Girls 12-17 years .....................................................................

Female equivalent

Girls:12 years .. .. .. .... .. . ... ... .. ... .. .. .. .. . ..... .. ... . ..... . .. .. . .... ... .. ... .. ... .. .. .... . .13 years ..m.... ... . .. .. .. ... ... . .. . ... .. ... ... .... . .. .. .. .... .. . ... .... .. ... ... .. .. .... .. .

14 years .... .. .. .... .. ... ... . .. .. ... .. .. ... ... .. .... .. .... .. .. .. .. . .... .. ... .. .... . ... ....15 years ... ... ... .. ... .. ... ... .. .... . ... ... ... .. .... .. .. .. ... ... .. .... ... . .... .. ... ... .. ..16 years ... .. . ... .. .. ... .... .. .. ... ... . .. .. ... .. ... .. .. .. .. .. ... ... .... .. .. ... ... .. ... .. ..17 years ... .. ... ... . .... .. ... .. .... .. .. .. .. .. .. .... .. .. .... ... .. ... .. ... ... ... .. ... .. ... ..

White

I-h&

140.4156.8173.7187.1197.0205.8

174.3186.5197.9205.3211.5

211.7

175.2196.5

175.0196.7

142.3154.8167.9177.3185.8186.0

17.1717.7714.8413.9113.1210.97

14.3613.1210.46

9.2810.00

9.82

---.-.

-... . .

11.7210.89

8.878.018.788.63

Negro I Other racesI

Skeletal age in months

0.620.930.740.730.780.52

0.710.720.630.570.52

0.64

0.400.38

0.400.38

0.580.60

0.530.490.460.56

138.7160.6172.7181.7192.7202.4

178.4187.5198.7207.6210.2

210.5

172.6197.1

174.2196.1

146.4156.5169.1179.9184.2184.5

16.0419.6917.0415.9116.9311.37

16.7212.1012.82

8.359.36

10.34

----..

-..-..

13.7210.1010.91

7.248.209.06

2.843.102.031.092.931.65

2.401.091.700.810.96

2.14

1.170.85

1.180.84

1.970.911.450.700.841.88

149.3164.5170.7197.3188.9209.1

184.5187.2198.8204.6206.6

220.0

182.7198.4

179.2196.0

152.5156.2168.3175.9178.6197.0

105.5852.3754.06

5.0274.35

1.05

9.43132.41140.57

64.71146.06

155.56

6.323.80

6.293.78

7.79110.50

119.0055.63

126.26139.30

NOTE: R = mean skeletal age (hand-wrist); SX = standard deviation of skeletal age; and s= = standard error of mean. Expectedvalues remove the effect of differences in the chronological age dktribution with respect to skeletal age over the 12-17-year age span byindirect adjustment.

53

Table 2. Mean, standard deviation, and standard error of the mean skeletal age (hand-wrist) of youths by geographic region,chronological age at last birthdav, and sex: United States. 1966-1970

Standard of reference, sex,and chronological age

at last birthday

Male standard

Boys:12 years .... ... .... .. . ... .. ... ... .. .. ..

13 years . .... .. .... .... .. ... .. . .... .. ..14 years . ... ... .. ... . .... .. ... .. .. ... ..15 years .. .. .. .. .. ... . .... .. ... . .... .. .16 years ... .. .. .. .. .. .. .. .. ... . .. .. .. ..17 years . ... ... .. .. .. ... .... .. .. .. ... ..

Girls:12 years .. .. ... . .. .. .. ... . ... . .. .. .. .. .13 years ..... . .. . .. ... .. .. .. . ... .. .. ...14 years .... .... .... .. .. .. .. .... .. .. ...15 years .. .. ... .. .. .. ... ... .. .. ... .. .. .16 years .. .... ... .. .. . .. .. ... .. . .... .. .17 years .. .... .. . ... ... .. ... ... . .... .. .

Actual values:

Boys 12-17 years .. ... ... .. .. .. ...Girls 12-17 years ..... .. .. .. ... ...

Expected values:

Boys 12-17 years .. ... .. .. .. ... . ..

Girls 12-17 years .. .. .. ... .. .... ..

Female equivalent

Girls:12 years .. .. .. .. .. .. .. .... ... . .. .... . ..13 years .. .... .. .. .. .. .. .. .. .. .. .. ... ..14 years ... .. ... . ... .. ... .. ... .. .. ... ..15 years .. .. .. .. .... .. .. .. .. .. .. .. .. .. .

16 years ... . .... .. .. ... .. ... .. .. .. .... .

17 years ... .... .. ... . .. .... ... .. ... . ..

,–– ——-—

Northeast I Midwest I South I West


141.0

157.6173.6189.1196.2206.6

177.4187.9197.3

204.8210.8209.2

174.7196.4

173.9

196.4

145.4156.9167.3176.2

184.8

182.3

16.93

20.0215.0013.8213.2510.35

14.1313.0210.78

9.258.66

10.06

. . .

. . .

. . .

. . .

11.5810.87

9.147.96

7.59

8.77

1.14

2.601.021.451.331.42

1.460.961.23

0.820.941.27

0.840.72

0.83

0.72

1.200.791.040.71

0.82

1.11

139.0

157.9172.0183.6196.2206.3

173.3186.7198.5

205.2211.8211.1

174.0196.0

174.9

196.3

141.3155.0168.8177.2

186.2185.2

17.59

17.4514.9114.4813.26

9.66

14.8513.1911.42

9.379.809.85

. . .

.-.

. . .

. . .

12.1110.95

9.718.09

8.62

8.64

1.28

1.621.611.141.520.53

1.381.781.34

1.560.971.66

0.690.66

0.70

0.67

1.131.481.141.35

0.851.46

141.1

156.1174.2186.7196.6

204.4

175.7186.7197.6

206.9212.0213.0

175.9197.5

175.9

196.9

143.7155.0167.6178.9

187.0189.0

16.03

18.3415.8014.8814.2811.65

14.3012.8711.16

9.4611.95

9.22

. . .

..-

. . .

. . .

11.7010.68

9.478.18

10.54

8.18

1.62

1.321.871.021.040.72

1.351.030.81

0.741.221.40

0.910.96

0.91

0.95

1.100.860.690.64

1.081.24

140.2

157.8174.7187.6196.4

204.3

173.9186.4198.5

205.4210.5212.9

175.3196.6

175.0

196.9

141.9153.4168.8177.4

184.5

188.4

17.20

16.3214.6613.2014.3711.95

15.5812.64

9.698.459.179.32

. . .

. . .

. . .

. . .

12.7110.46

8.247.30

8.048.25

1.38

1.161.161.411.361,40

2.390.871.471.021.151.20

0.830.86

0.83

0.87

1.950.721.250.88

1.011.06

NOTE: -f = mean skeletal age (hand-wfi~t); Sx = standard deviation of skeletal age; and s= = standard error of mean. Expectedvalues remove the effect of differences in the chronological age distribution with respect to skeletal age over the 12-17-year age span byindirect adjustment.

54

Tabla 3. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by geographic region, chronological age at last birthdav, and sex: United

Standard reference, sex,and chronological age

at last birthday

Male standard

Boys:12 yams.., ... ... .... .... ... .... .. ... ... ... ... ..13 years,,,, .. .... ... ... ...oo.. ..io. ... ... ... ...14vems ..... ... ... .... .... .. .. .... ... ... ... ... .15y@ar$ ... .... .... ...o... ... .. .... .. .. . .... ... .16years ... .... .... ... ... ... .... ... .. .. . ... .... .17 ymr$.., . .. .... ... .... ... ... ... ... .... .. .... .

Girlx12years .. .. .. ... .... .... .. .... ... ... .. .... .. ...13 years .. .... ... .... ... ... ... .... .. .... .. .... ..14 veers ... ... .. .. ... ... ... ... .... .. ... ... ... ...15ycms .. .... .. .... .... ... .. ... .... ... ... .... . .16 Vears.l ... ... .... .. .... ....! . ... .. .... .... .. .17 Vmrs ..... ... ... .... ... ... ... .... .. .. .... .. ..

Actual values:BOVS 12-17 vaars .... .. .... ... ... ... .. .... .Girls 12-17 years .... ... ... ... ... ... ... ... ..

Expected vduas:BOV8 12-17 yeara ... ... .... ... .... .. .... .. .Girls 12-17 veals,,, . .... ... ... .... .. ... ... .

Female equivalent

Girls:12 years .... ... .... .. .. .. .. .... ... ... ... .. .... . .13yurs..o..u..u .. ....n.... ... ... .. .... ... ... ..14 ywars .... ... ... ... .... ... ... ... .. ... ... .... ..16 Vaars ... .... .. ... .... ... ... .. .... ... .. ... ....16 WWS,....... ... ... ... .. .... .... ... ... ... ... .17 Vm’s,,,................. +. ... ....o... .... ...

States, 1966-1970

Northeast Midwest South West

White Negro White Negro White Negro White Negro

z $~ E s? z % ~ s~ : Sj? ~ Sx ~ SF z SF


141.1157.4173.4189.6196.6207.3

177.0187.S196.8204.8211.1208.3

176,0196.4

176,0186,6

145.0156.8I 66.8176.6185.2I S2,6

1.242.630.821,631.441.24

1.331.201.271.070.991.13

0.990.S6

1,00),86

I .08I .00I .0s3.92),67),98

140.7158.s174.9164,6196.0200.0

179.41S8.5200.6204.9207.820S.6

172,3196.4

173.7196.8

147.4157.6171.6176.81S0.8181.6

1.567,663.06S,383.40S.88

4.S82.563.662.360.694.54

0.861.53

0.971.63

4.012.143.152.040.803.95

138.6157.2172.91B4,2196.9206.2

173.11s6.619B.2204.6211.7211.1

174.2195.9

174.6196.2

I 41.1155,2168.4176.2186.41S6.2

1.221,601.431.1s2.080.61

1,501 .9s1.461.731.001.74

0.840.71

0.64>.71

1.221.651.241.490.861.53

131.1164.5162.9176.1190.4206.8

174.91s7.5203,1211.2213.4211.1

172.4197.8

169.4198.4

142.9156.5174.11s5.4189.4185.2

2.663,844.523.352.824.61

9.842.442.992.161.922.93

3.161.86

3.111.67

3.042.042.56I .91I .702.57.

142.0154.5174.018B.5196.8206.1

174.91s6.6198.0206.6212.4213.3

177.3197.5

175.4197.3

142.9155.616B.O17S.6187.8169,3—

1.191.192.131 .0s1.140.92

1.331.130,500.691.511.30

0.920.86

0.910.88

1.080.940.420.601.341.15—

139.1159.4174.9181.4196.1199.1

177.s186,6196.4207.9211.1212.3

172.0197.5

172.9196.S

145.8155.2166.4180.8186.2167.6

5.854.343.501.101.762.14

3.741.852.311.401.334.06

2.161.63

2.191.62

3.07I .541.961.221.173.59

139.9157.4174.7187.3197.4203.8

172.8166.2198.4205.4210.9213.1

175.1196.5

175.2198.2

140.6153.2168.8177.4184.9189.1

1.761,551.171.581.271.44

2.220.931.561.091.220.97

0.s20.94

0.s20.94

1.810.771.330.941.070.B6

142.4166.5174.8186,7176.020B.3

182.7188.7198.9206.?204.0209.2

174.9196.2

173.7197.1

150.7157.7170.9176.1175.0182.4

7.6612.96

4.4441.9057.4646.76

57.8S2.741.202.754.97

47.65

6.641.87

6.591.8S

47.742.291.032.3S4.26

41.65

NOTE: S = mean skeletal age (hand-wrist) and sc = standard error of mean. Expected values remove the effect of differences in the chronological age distribution withrespect to skeletal age over the 12~i7:Year age span by hdirect adjustment.’

55

Table 4. Mean skeletal age (hand.wrist) of youths by population size in urban areas and land use In rural areas of residence, chronological ags at last birthday, and sax, with sdoctedstandard errors United States, 1686-1970

,

Standard of reference, sex,and chronological aga

at last birthday KI Urbanized areasUrban outside urbanized

Urban areas RuralRural-farm Rurd-nonfan

total3 million 1.0-2.9 250,000- Lessthan 25,000 1o,oQo- 2,Wo- total 10 acres Len thanor more

10 acrat L-s thanmillion 999,669 25JJ,000 or more 24,666 9,966 or more 10 acres or more 10 acrm

Male standard

BOYS:12 years ..... ................... ..... .13 yet,....,,...,, ............. .....14 years<,.,... ... ............. ..... ..15 yams ....... ... .. ... ......... ... ...16 years.... ... .... ............ ...... .17 years....... .... ................ .. .

Girls:12 years..., ...... ... .... .............13 years........ ... ................. ..14 years., ...... .. .. ..................15 years............. ... .. ............16 years ... .. ...... .... .. .. .. .. .......17 years ............ .... .. ... .........

Actual values:BOYS12-17 years .. .... .. .. .... ..Girls 12.17 years .... ...... ......

Expected values:BOYS12.17 years .............. ..Girls 12-17 years .............. ..

Female equivalent

Girlx12 years. .... ...... .... ...............13 years.... .... .... ................. .14 years...... .......... ........ ... ...15 years.,...,..,..,..,,,, ........... .16 YEWS..,.,.,.., ...................17 years... ... .................. .... ..

Male standard

Boys:12 years........................ ... ...17 years... .... ................ ..... ..

Girls:12 years .................. ...... ......17 years., .... .................. ..... .

BOYS12-17 yeers ............... ... .. .Girls 12-17 years.,,,.,., ............ ..

140.2157.6173.4187.1196,4205.6

176.0186.719S.2205.8210.7212.0

174.9196.6

174.7196.6

143.0155.0158.4177.8184.71B7,0

0.750.81

0.940.77

0.520.44

140.2159.0173.41BB.4196.1206.9

178.5187.5199.6207.5212,3208.6

175.6197.4

174.B196.0

146.5156.5170.6179.6187.4182,9

139.7155.7172.6185.1194.8205.5

173.2184.9194.B203.4207.6211.2

171.9195.2

172.8197.3

141.2152,9154.2174.4179.91B5.3

141.B166.7174.0190.8197.5205.3

173.9186.219B.7206.1212.0215.6

176.7198.0

176.6197.4

141.9154.3169.0176.1187.0191.6

2.031.91

4.390.9B

1.562.11

13B.6150.3175.5166.3197.1205.6

17391B8.O19B.6206,2211.6213.6

175.1197.4

174.3196.8

141.9157.0169.217B.2185.9189.6

Mean skeletal age in months

137.6163.0172.11B6.2189.1208,3

170.5190.4196.7204.1210.3212.6

174.9197.1

i74.0197.7

13B.5169.4155.7175.2184.3188.2

138.8160.4168.6162.6197.4202.5

171.4166.6199.4204,B208.B209.0

177.2193.3

176.7194.3

139.4154.9170.4176.2181.8182.0

141.3155.3173.9185.8196.1201.3

172.0186.2168.12U6.4210.7213.3

174.8186.3

175.9195.6

140.0154.3170.117B.4184.7189.3

Standard error of the mrnn

7.46 3.273,31 1.40

_L2.03 7.656.66 3.04

2.61 3.812.50 2.33

140.4156.4173.9185.3196,3m4.9

175.11B6.5197.7m5.2212,4210.6

174.9196.5

175.3196.6

143.1154,s167.7177.21B7.6184.6

3.40 1.78 0.8245.54 2.37 0.65

_L-L4.40 3.04 1.24SO.94 1.72 0.95

2.B5 2.04 0.676.04 0.99 0.36

137.0153.2174.9163.5200.4203.6

173.01BO.6197.2m3,8211.720B.1

176.0193.5

177.0196.1

141.0146.6167.2174.B186.0181.1

2.062.63

3.672.13

1.581.27

161.8190.3163.0191.2

189.2197.5m4.7193,6

212.0

163.B189.0

166.7193.1

156.2167.5176.0162.6

187.0

96.17149.91

9.018.14

134.1152.6173.31S4,2197.7204.7

176.61B7.1196.0210,7211,220B,4

177.1194,B

17s.1194.B

143.6156.1166.01B4.7185,3181,4

3,043.52

4.662,56

3.491.57

141,6157.4173.6186.2196.2205.3

176.31B8.3197.9205.2212.6211.6

174.4197.6

174.4197.1

143,3167.3167,9177.2187,8185,B

1.121.02

1.081.03

0,B50.46

56

Table 5. Mean. standard deviation, and standard error of the mean skeletal age (hand-wrist) of vouths bv annual familv income. chronological age at last


at last birthday

Male standard

BOYS:12 years ..............................................13 years ..............................................14 years ..............................................15 years ..............................................16 years ..............................................17 years ..............................................

Girls:12 years ..............................................13 years ............i .................................14 years ..............................................16 years ..............................................16 years ..............................................17 years ..............................................

Actual valuas:Boys 12-17 years ................................Girls 12.17 years .................................

Expected values:Boys 12-17 years ................................Girls 12-17 years .................................

Female equivalent

Girls:12 years ..............................................13 years ..............................................14 years ...o........................ ..................15 years ..............................................16 years ..............................................17 years ..............................................

-...——.birthday, and sex: United States, 1966

I

Less than $5,000I

$5,000-$9,999

139.5156.2174.0185.1195.6203.9

176.3185,3197.5206.3210.9211,6

174,5195,8

175.5195.8

144.2153.3167.5178.3184.9186.2

16.3419.2715.9015.4213.9111.18

16.3112.3711.458.71

11,8810,60

27.2818.04

. . .

. . .

I 3.3410.239.717.53

10.429.33

2.352.612.031,460.981.07

1.970,981.080.741.411.19

1.260.72

1.290.72

1.610.810.920.641.241.05

139.7159.2174.3186,3195.6205.7

173.5187.0196.6205,1211.0211.8

174.6195.5

174.6196.1

141.5158.0I 66.6t77:l185.0186.6

17.5917.6615.5714.1514.329.75

15.6513.4911.74

8.518.939,56

27.2518.04

. . .

..-

12.7611.259.957.357.838.42


0.960.780.860.971.210.66

1.120,990.890.470.820.98

0.569.61

).561.62

1.911.83).751.413.723.86—

141.6156.5172.1187.9198.7206.8

175.7187.3200.0205,0211.9211.4

175.5198.1

174.9197.9

143.7156.3171.0177.0186.8185.8

16.3117.7014.1513.4812.2011.78

12.2912.718.669.819.029.71

26.8417.02

------

10.0510.617.408.477.958.53

1.341.501.231.001.941.13

0:901.250.471.150.951.04

13.870.78

0.860.78

0.741.040.400.990.840.91

138.8154.4175.7183.6193.3204.7

178.1185,5198.0206.5211.4212.9

175.6197.0

177.1196.2

146.1153.5168.0178.5185.8188.8

2.513.662.262.171.251.80

2.371.321.201.171.272.08

2.069.69

?.08).68

I .94I .09I .02I .011.121.84

141.3155.8173.9189.3199.9205.7

173.2185.0199.3204.1211.3208.7

175.6197.9

174.8199.0

141.2153.0170.3175.1185.6181.7

2,282.421.491.812.642.51

1.392,201.091.501.191.66

1.401,00

1.391.02

1.131.820.931.291,051.45

NOTE: s = mean skeIetal age (hand-wrist); Sx = standard de~ation of skeletal we; and % = standard error of mean. Expected values remove theeffect of differences in the chronological age distribution with respect to skeletal age over the 12-17-year age span by indirect adjustment.

57

Table 6. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by annual family income, chrono-logical age at last birthdav. and sex: United States. 1966-1970

Standard of reference, sex, and chronological age at last birthday

Male standard

Boys:12 years ... .... .. ... ... .. ... ... .. .. ... .... .. ... .. ... .. ... ... .. .. ... ... .. ... ... ... .. .. ... ... .. ...

13 years ... . .... .. .. .... .. ... . .. .. .. .. .. . ... ... .. ... .. ... .. ... ... .. ... ... .. .. .... .. ... ... .. .. .. .

14 years .. . ... ... ... .... .. .... .. .. .. .... . ... ... ... .. .. ... ... .. .. .... ... .. .. ... .. ... .. ... .... .. ..15 years .. .... ... ... .. .. ... ... .. .. .... .. .. ... ... .. .. .. ... .. .... .. ... . .... .. .... .. .. ... ... .. .. ...16 years .. . ... ... .. .. .. .. .. ... .. .. ... ... .. ... .. .... .. .. .. .... ... .. ... ... .. .. ... ... .. .. ... ... .. ..17 years .. .. ... .. ... .. ... .. ... .. ... ... .. .. .... ... ... . .... .. ... .. .. .... .. .. .. .... .. .. ... ... .. ... .

Girls:12 years ... ... .. ... .. .. .... . .... ... .. .. ... ... .. .... . .. .... .. ... . .... ... .. .. ... ... .. .. ... ... .. ...13 years ... ... ... ... . .... .. ... .. .. ... ... .. .... .. .. .. .... .. ... .. ... .. .... .. . .... ... .. .. .. ... ... ..14 years .. . .... .. .... .. .. . . .. .. .. .. .. .. . .. .... .. ... .. .. ... ... .. .... .. ... .. . .... ... .. ... .. .. ... ..15 years . .... .. ... ... .. .. .... .. .. ... ... .. . ... .... .. ... ... .. ... . ... ... ... .. .. ... ... .. ... .. ... .. ..

16 years .. .. ... .... .. . .... ... .. ... .. .... . ... ... .. .. ... ... ... .. ... ... ... . .. ... ... ... .. .. ... . .... .17 years ... ... ... .. .. ... ... .. .. .... .. .. ... ... .. ... .. ... .. .. ... ... .. ... ... . ... .. .... .. .. .. ... ... .

Actual values:Boys 12-17 years ..... .. .. .. ... ... .. .. ... ... ... .. ... .. .. ... ... . .... .. .. ... .. ... .. ... .. ... ..

Girls 12-17 years . .. ... ... .. ... . .... .. .. .. .... .. .. ... ... .. .. ... ... .. .. .. .. .. .. .. .... .. .. ... .

Expected values:Boys 12-17 years .. .. .. .. .. ... ... .. .. ... ... .. .. . .. ... .... .... .... .. .. .. .... .. .. .... ... .. ...Girls 12-17 years .... ... .. .. .... ... .. . .... . .... ... ... .. ... .. .... . .... ... .. .. ... ... .. ... ... ..

Female equivalent

Girls:12 years ... ... .. ... ... .. .. .. .. .. ... . .. . .... ... . ... .. .. .... .. .... .. .. ... ... .. .... .. .. ... ...o. ... .13 years .. . .. .. . .... .. ... .. ... ... .. .. .... .. ... .. ... ... ... .. .. .. .... .. .... .. ... .. .. .... ... .. .. ...14 years ... .. .. ... ... .. ... .. .. .. .... ... ... . ... .. .... ... .. ... .. ... ... . .... .. ... .... . ... ... ... .. ..15 years ... .. ... ... .. .... . ... .. ... ... .. ... ... .. .. .. .... .. .. .... .. ... ... .. .. .... .. .... .. .. .... . ..16 years ... .. .. ... ... . .... .. ... .. ... .. .... .. .. .... .. .... .. .. .. .... .. ... ... .. ... ... .. .. ... ... ... .17 years .... ... .. .... .. . ... .. .... .. .. .. .... ... .. ... . ..... . ... ... .. .. ... ... .... . .... .. ..o. ... ....


139.9154.7173.5186.2196.4205.0

175.1185.1196.8206.1

211.3212.3

175.4195.3

175.1195.7

143.1153.1166.8178.1185.6187.6

2.322.57

2.511.891.201.19

2.831.191.240.90

2.071.45

1.520.95

1.510.96

2.320.981.050.7B1.811.28

138.5158.8175.1182.3193.5201.3

179.4185.8199.0207.0

210.2210.4

172.6196.7

173.3196.0

147.4153 .B170.0179.0184.2184.4

4.53

4.943.422.051.911.89

2.801.971.65

0.82

0.793.10

1.64

0.96

1.650.95

2.30

1.631.410.710.692.72

139.815B.4175.0186.8196.4205.7

173.2186.7196.4204.9

210.9211.7

174.9

195.4

174.7195.6

141.2155.4166.4176.8184.9186.4

0.96

0.930.881.021.190.70

1.071.110.90

0.630.931.12

0.64

0.70

0.640.70

0.870.920.760.540.B2

0.99

138.4164.1168.6180.7190.1206.0

176.0189.8199.1

207.1

212.2212.3

171.4196.8

173.6194.7

144.0158.1170.1179.21B7.4187.6

3.103.462.653.667.032.32

4.482.513.44

2,07

3.502.45

1.571.56

1.591.54

3.67

2.092.941.793.092.16

NOTE: Y = mean skeletal age (hand-wrist) and s= = standard error of mean. Expected values remove the effect of differences inthe chronological age distribution with respect to skeletaI age over the 12-17-year age span by indirect adjustment.

58

Table 6. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by annual family income, chrono-logical age at last birthday, and sex: United States, 1966-1 970–Con.

i 1$10,000 or more I Lessthan $3,000 I $15,000 or more

White

ZEI

141.5166.4172.4188.1198.6206.6

176.1187.1199.9204.8211,9211.5

175.4198.0

175.4198.1

143.1156.1170.9176.6186.8186.0

1.361.561.191,062.011.19

0.931,280,531.180.961,01

0.850.79

0.850.79

0,761.070.451.020.850.89

I I

Negro White I Negro White Negro

144.2162.5159.6177.2205.9211.8

183,9199.0200.8213.9209.8208.3

175.8206.6

177.1199.4

151.9170.0171.8189.9183.6181.3

10.0451.95

8.728.27

103.165.51

12.385.125.413.55

66,4946.72

5.222.29

5.242.25

10.234.374.633.15

58.1946.72

139.4154.4173.6184.1194.2206.8

177.8186.5198.0206.5213.3214.5

176.4197.4

176.1196.9

145.8155.0168.0178.5189”.3190.5


3.455.692.143.071.611.70

3.261.801.681.641.201.49

2.900.93

2.890.92

2.671.501.431.421.061.32

137.8154.5178.4182.8191.8200.9

179.0184.0198.1206.5208.2210.5

174.2196.1

174.8197.2

147.0152.0168.2178.5181.2184.5

3.395.073.693.241.753.10

2.532.672.681.241.944,56

2.531.42

2.541.44

2.082.212.281.071.694.00

140.8155.9174.2189.1199.7205.5

173.1184.4199.1203.9211.5208.7

175.5198.1

175.6198.2

141.1152.4170.1174.9186.0181.7

2.332.441.481.902.752.66

1.472.221.181.531.161.67

1.471.03

1.471.03

1.201.831.011.311.021.45

161.2

149.6188.7220,0209.0

170.1196.7202.9

196.0206.8

187.8197.0

181.2195.4

138.1166.7173.9

166.0178.8

80.69

105.79133.41155.56104.68

120.305.92

101.65

138.59146.22

60.284.74

60.204.72

97.675.02

87.12

117.38126.42

59

Table i’. Mean and standard arror of tha mean akalatal age (hand-wrist) of white and Negro youths by education of first parent, chronological age of youth at last blrthdav.

Standcrd of refarence, sex,and chronological aW

at last birthday

Male standard

BOYS:12yaers .... ... ... ... .. ... ... ... .... . .... ... .. ...13 W.3K,. ... .... .. ... ... .. .... .... .. .. .... .. ... .14 years ... .... .. ... ... .. .... ... ... ... ... .. ...15 years . .. .... ... .. .... .. ... ... ... ... .. .. ... .16 years . ... ... .. ... .... .. .... ... ... .. ... ... ... ..Ilyear% ... .... .. .... ... .. ... .. .... ... ... .. .... ..

Girls:12 yaara .. .. ... ... .... .. .... .. .. .. .. ... ..... .. .. .13 years .. .... .. ... .... .. .. .... .. ... .... .. .... .. .14 years,.,...,., .. ... ... ... ... ... .. .... ... ...15 years .. .... .. .. .. .. ... ... ... ... ... ... .... ..16veera .... .. .. .... .. .... .. .. . .... . .. ... ... .. .. .17 years ... .... ... .. ... .... ... .. .... .. ... ... .... .

Actual values:Boys 12-17 years .. .... ... ... .. .... ... ... .. .Girls 12-17 years., .. ... ... .... .. .... .. ... ...

Expacted valuas:Boys 12-17 years .. ... ... .. ... .... .. ... ... ..Girls 12-17 years .... .. ... .. ... .... ... ... .. ..

Femala equivalent

Girls:12 years .... ... .. ... .... .. .. .... .. ... ... .... ..13 years . ... ... .. ... ... ... ... .. .... .. .... .. .... ..14 years .. ... .. ... .. .... .. ... ... ... ... ... ... ... ..15 years . .... ... .. ... ... ... .. .. .... .... ... .. ... ..16 yaars ... .. .. ... ... ... ... ... .. .... .. ... .... .. ..17 veara .. .. .... ... .. .... ... .. .. ... ... .. . ... ... ..

and sex: United States, 1966-1970

Education of parent

Less than 5 years 5-B years 9-12 years 13 years or more

Whita Negro Whita Nagro Whita Nagro White Nagro

z SF x SE z SE z Sx x SE z SF % $~ E s%

Mean skaletal age in months

140.4156.9174.4187.5197.2206.1

174.41S6.719s.3205.5211.7212.0

176.5197,2

176.3197.4

142.4155.016s.4177.5166.01S7.O

0.790.970.790,770.B20.54

0.7s0.770,5s0,570.51o.5a

0,390.41

0.3s0.41

0.840.640.480.490.450.60

138,6161.0173.4183.0192.7203.4

179.61S8.4199,2207,6210.7210.9

173.7198.0

176.219B.7

147,6157.4170.2179.91s4.71S4.9

3.123.192.091,212.931.42

2.361.391.750.810.922.15

1.29D.97

1.30D.96

1,941.161.503.702,s11.8S—

136.C154.!174.818S.E197.2206.4

175.1lSB.2199.0205.8211.7212,0

176.S19s.7

17S.619s.9

143,1157.2170.0177.s186.01s7.0.

0,621.200.920.s10,s40.56

0.930,s90,820,510.500.68

0.430.45

0.430.45

0.760.740.530.440.440.60—

136.3159.0173,21s3.s192.9203.4

179.6189.7201.3207.6210.7210,9

173.3199.2

175,0187.9

147.5158.7172.3179.91s4.71s4.9

3.073.552.481.262.951.42

2.S51.191.420.s10,922.15

1.340.77

1,350.76

2.341.001.220.700.811.6s

138.S155.1174,6188.2197.5206.0

175.0187.9198,6205.6211.5211.7

176.419s,0

176.119S.2

143.0158.916s.9177.6185.81S6.0

0.611.090.840.79O,BO0.54

0.ss0.s20.660.520,520,64

0.410.42

0.410.42

0.720.6s0.580.450.460.56

137.3159.4172.81S2.3192.9202.4

17S.818S.7200.6207.6210,2210.5

173.019s.5

174.9197.4

146.8157.7171.6179.91B4.21S4.5

2.973.582.421.242.951.65

2.751.071.440.810.9s2.14

1.270.72

1.260.71

2.260.891.230.700.B41 .Sa

138.6155,2175.4188.7197.7206,3

175.21S8.31s9.1205.7211.6211 .s

177.719s.7

177.419s.9

143.2157.3170.1177.71S6.91S6.2

0.771.150.s70,s10,620.55

0.96O.BS0,610.610.600.87

0.410.46

0.410.46

0.780.740.520.440.440.59

137.2159.7173.6183.9192.9203,2

179.s1S9.4201.2207.6210.4210.9

174.4199.2

176.2197.9

147.8158.4172.217s.9164.41S4.9

3.263.s02.331.162.951.61

2.671.061,410.810.902.15

1.420.73

1.430.72

2,110.s91.200.700.781.8S

NOTE: Z = mean skeletal age (hand.wdst) and $X = standard error of mean. Expected values remove the effect of differences i“ the Chro”olo$cal sge distribution ~th1.3iIpCCtto skeletal age over the 12.17.year age sprm by indfrect adjustment.

Table 8. Salactad percentiles in the distribution of skeletal age (hand-wrist) for youths by race, geographic region, annual family income,nd sex: United States, 1966-1970chronological age at last bi;thday

Race, region, annual family income, and percentile

White

P75 .................................................................................................P513.................................................................................................P25 .................................................................................................

Negro

P75 ,., ,,, ,,.,,. .,,,.... .............................................................................P50 .................................................................................................P25 ............................ ...................... ...............................................

Northeast

P75 ........................m........................................................................Pfjo .m...............................................................................................P25 .................................................................................................

Midwest

P75 .................................................................................................P51J.................................................................................................P25 .......................m......o..o.o.............................................................

South

P75 .................................................................................................P50 .................................................................................................P25 .................................................................................................

West

P75 .................................................................................................P50 ............................................................. ....................................P25 .................................................................................................

Lessthan $5,000

P75 ....................................................................... ..................... .....P50 .................................................................................................P25 ..................................................................... ............................

$5,000-$9,999

P75 .................................................................................................P50 .................................................................................................P25 .................................................................................................

$10,000 or more

P75 .................................................................................................P50 ............m....................................................................................P25 .................................................................................................

Chronological aga in years at last birthday

Boys

12 years I 13 years I 14 years 15 years I 16 years 17 years

154.3140.0127.3

154.4134.7126.1

154.1142.0127.8

153.0137.3123.9

155.1141.0128.7

155.0138.6127.1

154.2138.8126.1

153.9137.7127.0

155.2142.1127.7

170.0158.3144.8

172.8163.5151.0

172.8159.4143.6

169.4159.8146.1

171.0157.1144.9

169.3158.5146.5

171.0157.6144.1

171.6159.7147.2

169.0159.7144.4

Skelatal age in months

182.1174.1165.6

183.7172.7161.7

182,8173.6163.4

180.8172.8161.5

182.8175.1167.0

181.3175.1166.6

181.9173.5166.8

183.5174.4166.1

180.7173.9160.9

198.4186.4177.2

195.4179.8170.2

200.5191.8178.4

195.7182.0175.0

198.1185.6176.5

198.2187.6178.5

198.3182.4174.5

197.1185.9177.3

200.0188.3178.2

206,3199.1189.5

205.2197,3181.9

205,5198,8189.2

205.0198.9188.1

207.3199.1187.9

206.0199.1189.5

207.0198.5186.5

206.0198.6188.5

206.2200.7192.9

213.1207.1199.6

210.6203.1195.7

216.0206.5199.5

213.2206.7188.9

212.9207.1197.9

211.0206.9198.7

211.6205.6197.1

212.7206.6188.8

213.6207.8200.0

61

Table 8. Selected percentiles in the distribution of skeletal aga (hand-wrist) for youths by rata, geographic region, annual family income,. chronological age at last birthday, and sex: Unitad States, 1966-1 970—Con.

Rata, region, annual family income, and percentile

White

P7!5.................................................................................................P50 .................................................................................................P25 .................................................................................................

Negro

P75 .................................................................................................P50 .................................................................................................

Northeast

P75 .................................................................................... .............P50 . .... .. .. ... .... ... .. ... ... .. ... ... .. .... ... . .. .. .. .... .. ... .... .. ... ... ... .. .. .... . .... ... .... ..

P25 .................................................................................................

Midwest

P75 .................................................................................................P5(J ... .. ... . .. ... .. ... ... .. ... ... .. .. ... .. ... ... .... . ... ... ... ... .... .. .. ... ... .. .. .. .. ... .... ... ...P25 .................................................................................................

South

P75 ..................... .................................. ..........................................P~o .................................................................................................P25 ....................................... ..........................................................

West

P75 .:...............................................................................................P50 .................................................................................................P25 .................................................................................................

Less than $5,000

P75 .................................................................................................P51J.................................................................................................

$5,000-$9,999

P75 ..................................................................................................P50 ...................................... ...................................................... .....P25 .................................................................................................

$10.000 or more

P75 .................................................................................m...............P50 .................................................................................................P25 .................................................................................................

Chronological age in yeare at last birthday

Girls (female ecmivalant)

12yaarsl 13yaarsl 14years I l!5yearsl 16yearsl 17 years

152.1142.7134.4

159.6146.8138.8

153.9

144.3

137.9

49.6

40.7

34.4

55.445.334.5

52.342.634.1

56.245.4

35.0

51.742.3

134.3

152.1142.8135.7

166.8156.2145.1

166.4156.9146.9

167.3157.4145.7

167.5

157.4145.3

166.9155.2144.8

165.7153.2145.1

163.5152.1145.4

167.4157.0144.5

167.2157.5145.8


176.4170.2162.3

180.0171.2

165.0

177.4

169.2161.7

178.5

171.5162.4

176.0170.2162.6

175.9169.4162.6

176,4168,9162.3

175.9167.9161.2

177.8172.1163.8

186.2177.9169.0

187.8181.1173.0

185.3

177.5167.9

187.0

177.5168.3

190.1179.2172.4

186.2177.4168.9

188.2178.0171.7

185.9177.4168.8

185.4178.4167.8

197.4187,4179.0

196.3185.9

173.7

196.3

185.3175.4

198.4

187.6178.4

200.1188.2179.6

192.7189.4179.6

197.2187.3179.6

195.2186.4175.9

197.6187.2179.0

198.2189.0177.3

197.3187,4172.9

193,9

185.6173.0

200.0187.2175.2

200.2189.7184.5

199.1191.2178.5

198.2

189.6178.6

199.5189.2177.5

197.6188.2174.7

62

Table 8. Selected percentiles in the distribution of skeletal age (hand-wrist) for youths by race, geographic region, annual family income,chronological age at last birthday, and sex: United States, 1966-1 970–Con.

Race, region, annual family income, and percentile

White

P75 .................................................................................................P5Q .................................................................................................P25 .................................................................................................

Negro

P75 .............................................. ...................................................P50 ............................................................. ....................................

Northeast

P75 .................................................................................................P50 .................................................................................................P25 .................................................................................................

Midwest

P75 ........................................................................ .........................P50 ...............m................................. ................................................P25 ... . ... ... ... .. ..... .. ..... . ... ... .... .. .... ... .. ... ... ... ... .. .. .. .. ... ... . ... .... .. .. .... .... . .

South

P75 ....................%............................................................................P50 .................................................................................................P25 ............................................... ..................................................

West

P25 .................................................................................................

Less then $5,000

P75 .................................................................................................P50 .................................................................................................P25 ............. ....................................................................................

$5,000-$9,999

P5~ .....m...........................................................................................P25 ............m...i................................................................................

$10,000 or more

P75 ....................................... ..........................................................P5(J.................................................. .......... .....................................P25 .................................................................................................

Chronological age in years at last bir;hday

Girls (male standard)

12 years 13 years I 14years 15 years 16 years 17 years


184.1174.7165.9

190.6178.8170.8

185.9176.3169.9

181.6172.7

165.7

186.9177.3166.0

184.3174.6165.2

187.2177.4167.0

183.7174.3165.6

184.1174.8167.7

196.8187.2177.1

196.4187.9178.9

197.3188.4177.7

197.5188.4177.3

196.9186.8176.8

195.7

185.2177.1

194.5184.1177.4

197.4188.0176.5

197.2188.5177.8

204.9199.2193.3

207.5200.2195.0

205.4198.8192.7

206.5200.5193.4

204.7199.2193.6

204.6198.9193.6

204.9

198.6193.3

204.6197.9192.2

205.8201.1194.8

211.8

205.9198.7

212.8208.1202.0

211.2205.9197.9

212.0205.5198.2

214.1207.1

201.4

211.8205.4198.6

212.8206.0200.7

211.6205.4198.5

211.3206.4197.8

220.3212.3207.0

219.3211.6202.7

219.3211.2204.3

220.9212.4206.4

222.1212.8207.4

216.7213.4207.4

220.1212.2207.4

218.8211.9204.6

220.4212.1207.0

220.8

213.0205.3

220.2212.3201.9

217.9211.4202.0

222.0212.1204.1

222.2213.7210.5

221.1215.2206.5

220.8213.6206.6

221.5213.2205.5

220.4212.8203.7

63

Table 9. Mean bone-specific skeletal ages for the 31 individual hand-wrist bones of white and Negro youths by chronological acre in yearsat la!


at last birthday

Mele standard

Boys:12 years .. ... .. ... .. ... .. ... ... ... .. ...13 years .. ... .. .. .. .... .. .. .. ... . ... ...14 years ... .. .. ... .. .... .. .... . ... .. .. .15 years ... .. .. .... . ... .. .. .. .. .. .. ....16 years .. .. ... .... . ... ... ... . .. .. .. ...

17 years .. ... ... . .. .. ... . .... .. ... .. ...

Girls:12 years .. ... .. .... .. .. .. .. .. ... . .. .. ..13 yaars .. ... .. .. .. .. ... .. ... ... .. .. ...14 years ... ... . .... .. .. .. .. .. .. .. .... ..

15 years .. .... .. ... . .... .. ... .. ... .. ...16 years .. .... ... .. ... .. .. .... . ... .. ...17 years .. ... .. .... .. .. .. .... .. ... .. ...

Actual values:

Boys 12-17 years ... .. ... .. ... .. ...Girls 12-17 years .. .. .... .. .... .. ..

Expactad values:

Boys 12-17 yaars ... .. .. .. .. .. .. ...Girls 12-17 yaars .. .. . ... .. ... .. ...

Female equivalent

Girls:12 years .. ... .. .... . ... .. .. .. .. ... .. ...13 yaars .. ... .. .... .. .. ... .. .. .... .. ...14 years .. ... .. .... . ... .. .. .. .. .. .. ....15 years .. ... .. .. ... ... .. .... .. ... .. ...

16 yaars .. ... .. ... .. ... .. ... ... . .... .. .17 yaars ... .. .. .. ... ... .. .... .. ... .. ...

Male standard

Boys:

12 years .. .... .. .. .. .... .. .. ... ... .. .. .17 years .. .... .. ... .. ... .. ... .. ... .. ...

Girls:12 yaars .... .. ... .. ... ... . ... .... .. .. ..17 years ... ... . ..... .. .. .. .... .. ... .. ..

Boys 12-17 years ... .. .. .. .. .... .. .. ... .Girls 12-17 years ... .. ... .. .... .. ... ... .

]irthday and sex, with selacted standard errors: U nitad States; 1966-1970-.

Radius Ulna Capitate Hamate Triquetral

Whita Nagro White Negro Wh ita Negro Wh ita Nagro White Negro


139.9156.7173.7186.919B.O207.5

173.2185.7197.8208.5214.2217.0

175.4197.6

175.2197.8

141.2153.7167.8181.8190.2194.0

0.660.51

0.730.41

0.420.37

139.0160.3171.8181.9192.8204.0

177.9186.5199.2209.5213.9217.7

172.4198.4

174.2197.1

145.4154.5169.2183.5189.9194.7

2.951.81

2.600.92

1.151.01

140.0156.1173.2186.3195.0202.2

172.8185.2196.6203.7206.6208.4

172.5191.2

172.4191.4

140.8153.2166.9174.0179.6181.4

0.640.64

0.800.37

0.520.39

139.5160.6172.3181.1190.6199.3

177.7186.6196.2203.8205.2208.2

170.6192.0

171.7190.8

145.7154.6166.3174.2177.3181.2

141.0155.7168.2175.6178.6184.9

168.2175.9182.0188.0185.4191.6

157.8173.3

157.5173.2

136.2143.9150.0157.0153.4161.6

140.1155.3164.2171.4167.1184.6

168.2175.2178.1

192.0192.0

156.0173.1

158.1173.6

136.2143.2146.1

162.0162.0

Standard error of the mean

142.1156.3168.8176.1179.6185.3

169.1176.5181.8188.7183.2191.5

158.4173.8

158.2173.8

137.1144.5149.8157.7151.2161.5

2.870.98

2.480.81

1.360.72

0.701.84

0.6660.59

0.810.50

2.7541.73

2.0196.00

2.471.26

0.651.75

0.6385.66

0.820.49

141.4157.1165.4173.1170.3184.9

169.1176.2179.0

192.0192.0

157.4174.0

158.9174.2

137.1144.2147.0

162.0162.0

2.7541.79

2.1796.00

2.481.49

140.8154.8167.8175.2178.6185.7

167.3174.9181.8188.4183.1191.6

157.3172.4

157.0172.5

136.2141.9149.8156.4151.1161.6

0.731.72

0.6660.59

0.820.51

139.5156.2164.0171.7167.5185.1

168.4174.8178.0

192.0192.0

156.1172.8

157.8172.8

136.5141.8145.0

162.0162.0

2.7041.81

2.21135.76

2.471.49

64

Table 9. Mean bone-specific skalatal agesfor the 31 individual hand-wrist bones of white and Nemo youths by chronological age in yearsat last birthdav and sex, with selected standard errors: Uni*~~ Stat= 19-66-1970—COn.

Standard of raference, sex,and chronological age

at last birthday

Male standard

Boys:12 years ..................... ..........13 years ...............................14 years ...............................15 years ...............................16 years ...............................17 years ...............................

Girls:12 years ...............................13 years ..................... ..........14 years ...............................15 years ...............................16 years ...............................17 years ...............................

Actual values:Boys 12-17 years..................Girls 12-17 Years..................

Expected valuas:BOYS12-17 years..................Girls 12-17 years .... .... ..........

Female equivalent

Girls:12 years ................... ...... ......13 yeers ...............................14 yaars ........................... ....15 years ...............................16 years ...............................17 years ...............................

Male standard

Boys:12 years ...............................17 years ...............................

Girls:12 years ...............................17 years ...............................

BOYS12-17 years .......................Girls 12.17 years .......................

140.6155.0167.7175.0178.1185.4

167.3174.7181.3187.9187.7191.2

157.1172.3

157.0172.4

136.2141.7149.3156.4156.0160.2

0.701.78

0.6060.47

0.740.50

139.3157.0164.6171.5167.01B5.O

16B.9175.5177.5

192.0

156.4173.0

157.8172.5

137.0142.5144.5

161.0

2.5641.81

1.90

2.261,21

139.2164.1167.4175.5178.3186.3

166.6174.6181.0187.6187.3190.4

156.6172.0

156.3172.0

134.6142.6149.0156.2155.6159.4

0.591.77

0.6042.59

0.760.47

Trapazium Trapezoid Metacarpal I

White Nagro Whita Negro White Negro


137.6156.1163.4171.3167.3183.9

167.4175.2178.4

‘190.6192.0

155.0173.0

156.8172.8

135.4143.2146.4

159.6161.0

138.3154.2167.7175.3178.5185.2

166.7175.1181.0188.618B.5192.0

156.3172.3

156.0172.2

134.8142.1149.0156.6156.5161.0

137.6155.7162.8171.3167.1185.1

167.1174.2178.3

191.3192.0

154.9172.5

156.6172.9

135.1141.1146.3

159.4161.0


2.8741.66

2.23135.76

2.311.38

0.591.77

0.6142.93

0.770.41

2.8341.81

2.25135.76

2.371.41

139.0154.7168.0175.5178.2185.3

167.0175.0181.2188.4188.4192.0

156.6172.3

156.3172.2

135.0142.0149.2156.4156.4161.0

0.611.77

0.5942.93

0.790.38

137.4155.6163.2170.8166.0185.1

165.6174.5179.7

191.3192.0

154.7172.3

156.9173.2

134.3141.5147.0

160.0161.0

2.9741.81

2.04135.76

2.441.52

138.8155.0169.6176.9179.8183.4

170.0177.2181.3185.1185.5185.8

160.2175.3

160.0175.5

138.0145.2149.4154.1154.5154.8

0.590.43

0.680.17

0.370.42

137.3158.0167.6172.9174.7182.4

172.0178.8179.0186.0186.0186.0

159.4176.5

160.4175.5

140.0146.8147.0155.0155.0155.0

2.621.95

1.6158.81

1.810,97

65

Table 9. Mean bone-specific skeletal agesfor the 31 individual hand-wrist bones of white and Negro youths by chronological age in yearsat last birthday and sex, with selected standard errors: United States. 1966-1970-Con.


at last birthday

Male standard

Boys:12 years ...............................13 years ...............................14 years ...............................15 years ...............................16 years ...............................17 years ...............................

Girls:12 yeare ...............................13 years ...............................14 years ...............................15 years ...............................16 years ...............................17 years ............ ...................

Actual values:Boys 12-17 years..................Girls 12-17 years ..................

Expected values:Boys 12-17 years..................Girls 12-17 years ..................

Female equivalent

Girls:12 yaars ...............................13 years ...............................14 years ...............................15 years ...............................16 years ...............................17 years ...............................

Male standard

Boys:12 years ...............................17 years ...............................

Girls:12 yaars ...............................17 years ...............................

Boys 12-17 years .......................Girls 12-17 years .......................

Metacarpal I I Metacarpal I I [ Metacarpal IV

White I Negro White Negro White Negro

138.6154.9171.6182.7188.5196.0

171.4183.2194.2198.4203.2204.5

165.3184.5

165.2184.6

139.4151.2164.2168.4174.2175.5

0.621.08

0.791.42

0.470.43

137.6159.4169.9177.2183.4195.2

173.6184.5193.5201.4204.2198.6

164.7184.9

165.7183.8

141.6152.5163.5171.4175.2168.6

3.012.52

1.8999.28

1.461.07

139.4155.5171.8182.2188.2194.2

171.9182.7192.8196.4200.2200.4

165.1183.5

165.0183.7

139.9150.7161.8166.4170.2170.4

0.620.91

0.741.35

0.390.44

White I Negro I White I Negro


137.9160.1170.2177.3182.0194.2

175.0183.8191.5199.6200.3200.0

184.7184.3

165.7183.0

142.5151.8160.5169.6170.3170.0

139.2155.4171.9182.1188.0193.7

171.6182.4192.8196.7200.3200.7

165.0183.5

164.9183.7

139.6150.4162.2166.7170.3170.7

137.9160.6170.5177.4182.2192.0

174.1184.5190.5200.5200.6198.6

164.5184.1

165.4182.9

142.1152.5159.5170.5170.6168.6

Metacarpal V I Pisiform


139.7155.8172.1182.8190.0196.6

171.9183.3194.6199.1203.1205.1

166.4185.6

166.2185.8

139.9151.3163.2169.1173.2176.1

2.952.20

1.8463.29

1.300.94

0.660.91

0.741.19

0.370.45

2.932.14

1.7399.28

1.290.94

0.671.10

0.720.97

0.410.36

138.3160.2171.3178.6184.0192.8

175.4184.2192.3201.3202.7204.8

165.6185.2

166.9184.3

143.4152.2161.2171.3172.7175.7

2.951.96

2.06102.45

1.170.94

141.4155.6167.7174.8179.1185.3

167.1174.8182.5187.0187.3192.0

158.0172.9

157.8172.8

135.6141.6150.5155.0155.3160.0

0.691.98

0.60

0.530.47

139.5157.6163.8171.6164.6186.9

166.7174.7178.9

192.0192.0

157.5172.2

159.4172.8

135.4141.7146.9

160.0160.0

2.4942.75

2.29135.76

1.571.48

66

Table 9. Mean bone-specific skeletal agesfor the 31 individual hand-wrist bones of whita and Negro youths by chronological age in yearsat last birthday and sex, with selected standard errors: United States, 1966-1970–Con.

Standard of refarence, sex,and chronological age

at last birthday

Male standard

Boys:12 yaars .......................... .....13 years ...............................14 years ...............................15 years ...............................16 yeers ...............................17 yeara ...............................

Girls:12 years ...............................13 years ...... .........................14 years ...............................15 years ...............................16 years ...............................17 years ...............................

Actual values:Boys 12-17 years..................Girls 12-17 years ..................

Expected valuas:Boys 12-17 years..................Girls 12-17 years ..................

Femala equivalent

Girls:12 years ...............................13 years ...............................14 years ...............................16 years ...............................16 yaars ...............................17 years ...............................

Male standerd

Boys:12 years ...............................17 years ....................... ........


Boys 12-17 years .......................Girls 12-17 yaars ... ....................

Adductor Flexor Proximal Proximal Proximalsesamoid sesamoid phalanx I phalanx I I phalanx Ill

I

Whita I Negro White

159.7164.7170.4175.5178.6183.4

169.4174.3179.4180.1180.8184.8

168.8173.6

168.7173.7

137.4142.3147.4148.1148.8152.8

0.551.36

0.632.07

0.370.35

159.9167.0169.9172.2169.0184.4

172.3175.0174.8178.8184.8186.3

168.4174.5

169.2173.6

140,3143.0142.8146.8152.8154.3

1.1458.91

1.5472.21

1.231.32

165.4168.4172.0176.0178.7185.0

171.6175.9180.6180.5184.0186.3

172.3175.5

172.0175.6

139.6143.9148.6148.5152.0154.3

0.672.13

0.552.05

0.420.43

I I I

Negro White Negro White I Negro White


163.9169.1172.5172.4167.6186.9

174.6175.2176.5192.0184.8190.5

170.8176.4

172.3175.8

142.6143.2144.5161.0152.8159.5

140.8157.0172.9183.7189.1198.8

174.5184.5195.7202.8206.5207.7

165.8185.6

165.6185.9

141.5152.5165.7173.8178.5179.7

139.4160.7171.3175.8183.6196.4

177.3186.9193.7206.7206.5208.6

165.0187.0

166.5185.6

144.3154.9163.7178.7178.5180.9


2.1759.94

1.7195.27

1.591.06

0.641.22

0.691.21

0.460.50

3.292.96

1.8946.66

1.601.00

141.0157.5172.5183.2188.4195.9

174.9183.4193.1198.6201.8202.9

165.2183.7

164.9184.0

141.9150.7163.0168.6171.8172.9

0.661.17

0.671.16

0.480.44

138.2160.6170.5176.3180.3194.2

176.3185.9192.1202.2202.6204.0

163.7186.0

165.8184.8

143.3152.9161.2172.2172.6174.0

3.001.87

1.8045.61

1.731.11

141.0157.8172.6183.4187.9196.1

175.1183.6193.7199.0202.4203.3

165.4184.3

165.1184.5

144.0151.6163.7169.0173.4174.3

0.631.18

0.670.86

0.460.41

Negro

138.3161.0170.8176.8180.6194.3

177.1185.9192.7202.6202.6204.0

164.0186.3

165.9185.0

145.1153.9162.7173.6173.6176.0

2.901.85

1.9579.00

1.701.19

67

Table9. Mean bone-specific skeletal agesforthe31 individual hand-wrist bones oftiite and Negro youths bychronologiml a@ in yearsat Iastbirthdav andsex, with selected standard errors: United States .1966-1970 –Con.

Standard of reference, sax,.nd chronological age

at last birthday

Male standard

Boys:12 years ...............................13 years ...............................14 years ...............................15 years ........................... ....16 years ...............................17 years ....... ........................

Girls:12 years ...............................13 years ...............................14 years ...............................15 years ...............................16 years ...............................17 years ...............................

Actual values:Boys 12-17 years., ................Girls 12-17 years ..................

Expected values:Boys 12-17 years..................Girls 12-17 years ..................

Female ecruivalent

Girls:12 years ...............................13 years ...............................14 years ...............................15 years ...............................16 years ...............................17 years ...............................

Male standard

Boys:12 years ...............................17 years ...............................


Boys 12-17 years .......................Girls 12-17 years .......................

Proximalphalanx IV

E

141.0157.6172.9183.4188.4195.5

175.4184.0193.6198.7202.4203.0

165.3184.5

165.0184.8

144.2152.0163.6168.7173.4174.0

0.681.22

0.670.80

0.460.40

138.4161.1170.6176.6180.4193.3

177.8186.3192.3203.0202.8204.0

163.5186.8

165.5185.4

145,8154.3162.3174.0173.8176.0

3.091.89

1.8545.61

1.941.13

Proximal Middle Middlephalenx V phalanx II phalanx I I I

White Negro White Negro White I Negro

141.2157.5172.5183.3188.0195.7

175.7183.9193.4199.6202.2203.4

165.1184.6

164.9184.8

143.7151.9162.4168.4173.1173.7

0.681.25

0.650.70

0.460.44


138.8161.6171.1177.0181.3192.4

177.4186.4193.2202.8202.8204.0

164.0186.7

165.6185.3

145.4154.4162.2173.4173.4174.0

141.9157.5172.6182.6188.2195.2

175.1184.1192.8199.2202.3202.9

165.5183.9

165.3184.0

143.1152.1162.6170.1172.4173.4

139.8160.9170.3176.1181.9193.8

176.8185.2191.0200.3202.4204.0

164.4185.2

166.1184.6

144.8153.2160.0170.6172.6175.0


3.071.95

1.7145.61

2.021.12

0.651.01

0.700.68

0.500.39

2.882.19

1.80102.00

1.890.99

141.8157.6172.8183.1188.0195.6

175.3184.4193.5198.9201.7203.0

165.8184.4

165.6184.5

142.4152.4162.5169.4172.7174.0

0.630.85

0.640.66

0.490.41

140.1161.0170.4176.8183.6194.9

176.8185.2192.1200.3202.2204.0

165,3185.7

166.7185.1

144.7153.2161.1171.3173.0175.0

2.851.91

1.61102.00

1.850.96

Middlephalanx IV I~~

White I Negro

141.1157,1172,8182.8187,9195.0

174,9184.4193.2198.7202,4203.0

165.4184.2

165.2184.4

141.9152.4162.2169.4173.4174.0

0.660.93

0.690.67

0.470.42

139.1160.8169.5176.2183.0195.6

177.1185.6192.3200,1202,0204.0

164.7186.1

166.3185.2

145.1153.6161.3171.1173.0175.0

2.952.16

1.6379.00

1.781.02

68

Table 9. Mean bone-specific skeletal ages for the 31 individual hand-wrist bones of white and Negro youths by chronological age in yearsat last birthdav and sex. with selected standard errors: Unit~~ States. 1966-1970—COn.


at last birthday

Male standard

Boys:12 years ....... ...............13 years ......................14 years ......................15 years ......................16 years ......................17 years ......................

Girls:12 years ......................13 years ......................14 years ......................15 years ..................... .16 years ......................17 years ................. .....

Actual values:Boys 12-17 years .........Girls 12-17 years .........

Expected valuas:Boys 12-17 years ....... ..Girls 12-17 years .........

Female equivalent

Girls:12 years ......................13 years ......................14 years ................. .. .. .16 years ......................16 years ......................17 years ......................

Male standard

Boys:12 years .......... ............17 years ......................

Girls:12 years ......................17 years .................. ....

BOYS12-17 years ..............Girls 12-17 years ..............

---- ._..., —.—

Middle Distal Distal Distal Distal Distalphalanx V phalanx I phalanx II phalanx Ill phalanx IV phalahx V

1 I I I

White Negro White Negro Wh lte Negro White Negro White Negro White Negro

Mean skeletal aga in months

141.4157.3172.6182.9187.8194.8

175.1183,9192.7198.5202.2202.9

165.4183.6

165.2183.8

143.1151.9162.4168.5172.2172.9

0.640.99

0.710.72

0.490.40

139.8160.4169.3176.4183.2193.8

176.3185.6192.0199.7202.2204.0

164.4185.5

166.1184.7

144.3153.6161.0169.7172.2174.0

140.0155.7168.7176.7180.9184.8

170.9178.4183.2186.8187.2185.8

159.7176.1

159.4176.2

138.9146.4151.1153.8154.6152.8

12.85 0.662.38 0.92

1.80 0.6479.00 0.84

1.81 0.401.04 0.34

138.7156.4165.7170.0173.4183.4

169.9178.1183.9190.0186.0191.0

157.8176.5

159.9176.6

137.9146.1151.4160.0153.0161.0

2.912.32

2.0075.07

1.921.38

140.3156.0169.2176.6180.5185.2

171.0178.7183.6186.7187.2185.8

160.2176.3

159.8176.3

139.0145.4151.6154.7‘155.2153.8

137.6157.6165.0169.8172.6181.0

170.4178,8184.0190.9185.9190.9

157.5176.6

160.2176.4

138.4145.9152.0160.7153.9160.7

140.3155.7169.0176.2180.0184.8

170.6178.3182.1186.7187.4185.8

160.6175.9

159.6176.0

138.6146.3150.1154.4155.4152.9

137.7157.8165.5170.0172.5181.3

170.6178.6182.6191.0185.9191.0

157.7176.5

160.0176.1

138.6146.6150.6161.0152.9161.0


0.650.79

2.801.90

0.640.85

0.67 2.06 0.610.90 75.07 0.85

0.380.36 L_1.70 0.33

1.44 0.36

2.812.03

1.8975.07

1.681.43

140.6155.9169.2175.8179.0183.8

170.4176.4181.1185.7186.0185.9

159.6175.2

159.3175.2

138.4144.4149.1152.8153.0152.9

0.660.60

0.580.07

0.410.43

137.9157.5166.0169.9173.0181.8

170.6176.9178.6186.0186.0186.0

157.8174.9

160.0175.0

138.6144.9146.6153,0153.0153.0

2.901.76

1.9893.00

1.681.28

140.5156.0169.0175.6179.3183.6

170.4176.6181.3185.7186.0185.9

159.6175.3

159.3175.3

138.4143.6149.3153.7154.0153.9

0.660.64

0.620.10

0.410.44

138.0157.3166.0170.2173.4181.1

170.5176.9178.5186.0186.0186.0

157.9I 75.0

160.0175.2

138.5143.9145.5I 54.0I 54.0I 54.0

2.972.11

2.0133.00

1.571.31

69

Table 10. Mean bone.specific skeletal agesfor the 31 individual hand-wrist bones of youths by wographic region, chrmolcqical age in years at last birthdav. and sex, with selmtnd ttanckrd

Standard of reference, sex, and chronological a~at last birthday

Male standard

Expected values:BOYS12.17 yean ...... ......................................... ... ............ .. .. .. .... .Girls 12.17 years ..... ................... .................. .... ..... ..... ..... ...... .... ..

Ma[e standard

errors: United States. 1966-1970

North.east

140.4157.2173.1189.0196.4m9.4

176.7166.6197.8207.4215.6216.6

174.8196.0

173.9197.3

144.4154.6167.8180.4192.6193.6

1.190.78

1.400.77

0.940.81


139.2157.8172.2163.1196.4207.6

172.3186.3197.4208.4213.s217.3

174.2197.1

175.1197.4

140.3154.3167.4181.8169.8I 84.3

1.480.67

1.650.47

0.740.67

140.3166.4173.8186.7197.2m5.5

174.5166.0197.9210.1214.2216.9

176.0198.5

176.2198,1

142.5154.0167.9164.1190.4193.9

139.6157.2174.9167.7197.6206.2

172.6184.3196.9208.3213.4217.5

175.6197.6

175.1196.1

140.6152,3168.9181.6189.4194.3

1.88 1.350.92 1.56

1.43 2.780.77 0.73

0.93 0.930.97 0.89

140.2157.2172.9188.5195.2202.7

176.7165.6196.8203.2m7.6208.6

171.6t91.9

170.8191.0

144.7153.6167.6173.4180.618t.6

139.2157.0171.6162.9194.0202.3

171.8185.5196.4203.6m6.7208.8

171.8190.9

172.6191.2

139.8153.5166.8174.2179.7161.8

141.5155.8173.61s5.4194.0ml.0

174.2166.0196.5204.6205.6207.2

173.4191.6

173.4191.4

142.2154.0167.0175.6178.2180.2

139.3156.9173.9187.1184.6201.6

171.5164.4196.7203.4m5.6206.6

172.5191.0

172.2191.7

139.6152.4167.4173.6176.2181.6


1.130.48

1,6a0.91

1.010.66

1.531.34

1.750.48

1.040.75

1.690.47

1.490.83

1.030.57

1.241.25

2.700.67

0.960.51

Capitate

141.2155.1166.5176,6177.9180.4

170.2177.6182.1164.9192.0191.2

157.4175.2

157.2173.6

138.2145.6160.1152.9162.0161.2

1.3341.01

2.060.83

1,66O.oa

140.1156.3167.2173.2177.7191.2

167.9175.5181.3190.9192.o192.0

157.1172.9

157.5173.0

135.9143.5148.3160.8162.o162.0

1.3495.62

1.63[35.76

1.741.19

141.7164.2166.7174.3774.2185.6

166.6176.0178.6184.2189.7

167.2172.7

157,8173.1

136.2143.0146.6152.2156.7

1,662.42

0.98

1.410.72

140.7167.3168.6176.2177.1184.4

166.7175.4184.1187.2183.7192.0

166,6172.6

167.8173.3

135.4143.4162,1166.2161.7162.0

1.6641.34

1.9296.00

1.361.43

70

Table 10. Mean, bone-specific skeletal ages for the 31 individual hand-wrist bones of youths by geographic region, chronological age in years at last birthday, and sex, with selectedstandard errow United States, 1966-1970—Con.

Hamate

*

tral I Lunate

North.east

ScaphoidStandard of reference,sex, and chronological

w at last birthday TSouth WestI

South West I North- Mid-east wtst


Mid-west ‘outhI ‘“t

Male stnndard

BOW:12 years..... ....... .. .........13 years........... .. ... .......14 yaws ..................... ..16 yours.., ....................16 years....... .... ............17 Ynnrs....... ...... .... .. ....

Girls:12 veals.., ....................13 year,..,,.., ... ............14 years..,..,., ...............16 years........... .. .. ........16 years,..,, ............ ... ...17 years.......................

Actual VdU9S:

BOVI 1217 yews. ........Girl: 1217 years ..... ....

Expncted VdUOS:

BOY* 12-17 years .........Girls 12-17 years .... .... .

Female Equivalent

Girls:12 years........... .. ...... ....13 years.......................14 Yearn .... ...... ...........!.16 Yearn .........! .... ........16 Boom,,,., ...... ... .........17 vets ................. .. ....

Male standard

Boys:12 years,.,.,.,., ..............17 yaers.......................

Girls12 years. .......... ............17 years... .............. .... ..

Boys 12.17 yeers ..............Girl] 12.17 yOllr$... .. ... .......

142.0156.016B.B177.2176.1lB1 .0

170.8177.8182.27B4.7192.0191,2

157,8176.6

157.B174.3

13B,8145.6150.2152,7162.0161.2

1.2640.99

1,770.83

1,690,69

139.6155.2166.6172.6177.7190.8

167.4174.3180.7191.5192.0192.0

155.4172.3

157.0172.3

136.2141.3146.7160.5161.0161.0

136.6154.3165.8172.B176.8192.0

165.2174.1179.7191.5192.0192.0

155.6171.6

156.3171.9

134.2142.1147.7160.5161.0161.0

139.5153.2165.6173.6175.0184.6

167.0174.3178.6184.21B7.5

155.8171.8

156.5172.1

136.0142.3146.6152.2156.0

138.B156.1168.7176.8177.2167.1

165.B174.0183.4183.9187.7

157.7171.5

156.7172.0

133.9142.o151.4151.9156.4

141.0156.B167.6173.6178.7192.0

186.3176,5181.B180.9192.0192.0

167.7173.4

158.3173.7

136.3144.5149.B160.8162.0162.0

1.2996.00

1.17135.76

1.740.94

143,0154.9167,1175.2174.1186.1

169.7175,2178.4192.0169.7

167.7173.2

15B.4173.7

137.7143.2146.4162.015B.7

1.%2,28

1.29

1.460.97

142.415a.1169.8177.4179.9184.5

188.2176.3184.0188.0160.5192.0

159.7173.4

158.6173.8

136.2144.3152.0157.014B.5162.0

1.3441.33

1.88135.76

1.361.46

141.3155.3167.9176.7177.8183.4

169.2176.4181.2164.4192.0190.9

157.5174.0

156.8172.6

136.7143.4149.2152.4162.0160.9

138.7165.6166.3172.1177.7192.0

187.3174.3181.8190.8192.0192.0

156.4172.1

157.0172.3

136.1141.3149.8160.8162.0162.0

141.4163.6166.3174.5173.21B6.1

167.4174.5178.5192.01B6.9

156.7172.0

157.3172.S

136.1141.5145.5162.0156.9

140.4155.7166.8176.1177.9164.6

166.5174.7164.o186.4180.6192.0

158.1172.1

157.4172.5

135.5141.7152.o156.4146.6162.0

140.0164.5168.1176.1176.7183.4

168.7176.2181.4184.4192.0189.8

156.6173.8

156.6172.7

136.8143.2149.4152.4161.0158.8

141.5154.4166.2173.9173.6185.2

167.9175.017B.O192.01B8.1

156.9172.2

157.2172.3

136.4142.0146.0161.01’67.1

1.362.35

1.16

1.250.72

140.7157.1166.5175.8176.8184.2

166.2173.9183.1163.0187.3

156.3171.6

157.3172.4

135.2140.9151.1151.0155.6

1.7341.30

1.54

1.351.40

139.2154.1167.9176.S176.8162.5

166.2176.5161.2184.4

190.0

158.4173.8

156.0172.6

136.2144.5149.2152.4

159.0

1.1341.55

1.661.52

1.750.87

8ta”dard error of the mean

1.29 1.3341.46 96.00

1.80 1.6295.44 96.00

1.89 1.750.71 1.12

1.39 1.66 1.29135.76 2.60 41.90

0.93 1.37 2.0096.00 - -

1.51 1.36 1.560.90 0.97 1.51

1.562.31

1.36

1.440.92

1.6341.36

1.6a135.76

1.381.43

1.1841.46

1.6094.90

1.660.60

1.1595.38

1.4296.OQ

1.571.21

71

Table 10. Mean bone-specific skeletal ages for the 31 individual hand-wrist bones of youths by geographic region, chronological am in years at last birthday, ●nd *x, with atlwtdstandard errors: United States. 1866-1 970–Con.

Trapezium Trapezoid Metacarpal I

North- Mid- North-South west

Mid-east west east SouthWe&

Metacarpal IIStandard of reference,sex, and chronological

age at last birthdayNorth. Mid-east west ISouth

Mid-W9st

West

Male standard

soys:12 years.................. ...... ...13 years............... ... ..... .. ..14 years....... ............ ........15 years...........................16 yea= ...........................17 yea . ................ .... ... ...

Girls:12 years...........................13 years...................... .....14 years.............. .... .... .....15 years.......... .............. ...16 years...........................17 years...........................

Actual values:Boys 12-17 years .............Girls 12-17 years ............ .

Expected values:SOYS12-17 years .............Girls 12.17 years .............

Female equivalent

Girls:12 years.... ... .... ... .. .. .........13 years...........................14 years.. .... .......... ........ ...15 years... ............... ...... ...16 years . ...... ...................17 years...........................

Male standard

Boys:12 years... ........ .. .... ..... .. ...17 years... .......... .... .. .. ......

Girls:12 yea. ....................... ...17 years... .... .... ............ ....

Boys 12-17 years ..................Girls 12-17 years...................

Mean skeletal ags in months

138.4 138.4 139.1156.0 153.2 155.s166.8 166.1 16s.7172.9 173.9 176.3

137.5 13s.4155.1 153.0166.6 165.6172.5 174.117s.0 173.s192.0 185.3

166.7 166.4174.5 174.5180.0 179.4191.5 1s4.4192.0 189.2192.0 -

155.6 155.5171.9 171.7

156.0 156.5172.0 172.2

134.8 134.7141.2 141.2148.0 147.4160.0 152.4161.0 157.2161.0 -

138.4163.6168.0176.7176.0161.6

15a.5176.2181.11s4.7192.0192.0

155.6174.0

155.6172.6

136.5143.2149.1152.7161.0161.0

1.4s40.s9

1.41

1.900.76

13S.6165.616s.3176.117s.1185.5

165.6174.s1S2.31ss.51s7.s

157.4171.7

156.4172.2

134.2141.4150.2156.5155.6

1.4241.57

1.66

1.301.1s

138.2154.1767.6176.6175.6181.6

16S.9176.41s1.11S4.4192.0192.0

156.1174.2

15s.9172.9

136.4143.4149.1152.4161.0161.0

1.2740.99

1.61

1.910.s7

136.6154.4168.1177.217s.41S4.4

171.9177.61s1.01S4.21S6.0166.0

15s.9176.4

15s.1175.6

140.s145.6149.0153.2155.0155.0

137.7156.116s.2175.7179.4184.4

16S.7176.71S1 ,21S5.6164,51s5.7

160.3174,5

?60.6175.4

136.8144.7149.4154.6163.5154,7

139.8155.0169.6176.4179.4182.1

172.0176.4179.11S5.41S6.01S6.0

161.5176.1

161.2175.2

140.0146.4147.1154.4155.0155.0

1.SQ0.S6

1.27

1.030.5s

13S.6155.9170.4176.6177.s182.6

15s.1177.21S2.61S5.41S6.01S6,0

159.6175.2

159.2175.6

137.1145.2151.6164.4155.0155.0

1.291.26

2.0366.61

O.sa0.56

139.6155,3170.81S3.6166.7199.2

173.4164.7192.7197.6204.7203.1

164.51S4.8

164.0164.2

141.4152.7162.4167,6176.7174.1

1.251.72

1.692.19

0.811,05

136.s158.1170.6180,S18s.8196.0

170.0162.7194.6199.2204,3204,6

165.21S3,8

166.s1s4.4

13s.0150.71S4.6168.2175.3176.6

1.241.35

1.463.91

0.s30.9s

139.8154.7172,21s1.3187.1192.6

172.4162.3195.1199.1201.4204,5

166.2184.7

166.31s4.6

140.4160,3165.1169.1171.4176.6

1.s11.42

1.061.60

0.760,s2

136.3156.0172.21s3,31s5.7196.9

171.71S3.8193.s199,0202.1204.3

16s.0186.0

164,7166.0

13%7161.8163.8169,0172,2176,3

1.642.0s

2.732.65

1.310,91

177.1 174.0 177.7192.0 1S5.2 1S5.7

166.6 166.2 165.S174.4 174.s 174.61s0.2 178.7 1S3,2191.4 177.0 1s8.6192.0 189.8 187.3192.0 - -

156,1 155.7 157.5171.6 171.6 171.6

166.2 156.7 156.6172.0 172.4 172.2

134.9 134.6 134.4141.4 141.s 141.614S.2 147.4 151.2160.4 144.0 157.6161.0 157,s 155.3161.0 - -

Standard error of the mea”

1.31 1.65135.76 2.5s

0.99 1.2196.00 -

1,W 1.390.94 0.93

1.4041.57

1.12135.76

1.1096.@3

1.531.13

1.502.53

1.090.91

1.5593.oa

1.171.06

1.261.04

1.290.28

0.570.79

1.54 1.61

1.361.13

1.320.96

72

Tqble 10. Mean tvme.:paclflc akeletal ages forthe31 individual hand.wrlst bones ofyouths bygeographic region, chronological age Inyears atlastbirthday, andsex, with selectedstandard err.ars: Llnited States, 1966-1970-Con.

Standard of reference,SOX,and chronological

ago at loft birthday

Mdo standard

BOW:12 years ....... ...... .......... ......13 yearn.,.,., ................ ......14 years .......................... ...16 Ware..,,,,..,,,, ... ..............16 years ........................ .....17y0ar$ ........... .. ...$.....! .....4

Girls:12y08ra .,.,.,,..............,,,.,,,<13 year:, <.,,,,,.,.,,,.......,..,.,,.14 years .,.,,,...............,..,,,,,15yean ..... .................... ....16 years ..,,,,.,,, ........... ..... ...17 yaam..)..., ..........! ......!...i

Actual VdUE!l:Boys 12.17 years ... .. ..........Girls 12-17 years..,, ............

Expected VdUOt:Boys 12-17 yaam ........ .... ...Girls 12-17 years... .............

Famdu oqulvdent

(31rli:12y0ars.io ........................ ..13 years..,,,.., ....... ............ ..14 yaart ... .. ............. ...........15yaars ....... ...!...! ..! ......... ..16yoar$ ....... .................... ..17 years ....... .... ... ...............

Male standard

60ys:12 years ........................... ..17yesrs ............... .. ............

Girls:12 yenrs.. i., . .......................17 ymrs ................ .. ...........

Boy] 12.17 yam,,,,,, ... ............Girls 12-17 years .......... ...........

M.9tacarDal 111 I Metacamal IV I Metacamal V I PkiformI

North- Mid-South west

North- Mid.South West

North- Mtd- North- Mid-east west east west east

Southwest

west Southeast

Westwest


140.2166.9171.41S3.2187,7196.0

173.61s4,4191.9196,2201,3201.6

164.21B4,3

163.7163.6

141.6152.4160.9166,2171.3171.6

1.281.61

1.642.39

0,901.06

137.6156.6171.0179.7188.6196.6

170.6182.1192.9196.7199.1199.s

165.1162.4

165.6183.3

13S.6150.1161.8166.7168.1169.6

1,190.s5

1.453.52

0.670.8S

140.6165.3171.61s1.1166.6191.7

173.61S2.6192.6196.6196.3201.4

166.0183.9

166.1163.6

141.6150.6161.6166.616S.3171.4

1.671.20

1.151.86

0.B30.66

139.0158.6172.3183.31B5.4194.5

172.2182.6193,0197.2201.2200.0

164.9164.0

164.6184.0

140.2150.6162.0167.2171.2170.0

1,622.36

2,651.93

1.010.96

140.2155.8171.5163.61B6.6195.7

173.81B3.8181.4197,2202.0201 .s

164.3164.5

163.7183.6

141.s151.s160.4167,2172.0171.8

11261.76

1.562.17

0.961.11

137.5156.6171.1179.61B7.9195.4

170.2162.3192.5197.619s.9200.1

164.9182.6

165.5183.4

13B.2150,3162.o167.6168.9170.1

140.0155.6171.7161.5187.0190.0

173.0182.4192.5196.2198.4200.9

165.81B3.6

166.0183.4

141.0160.4162.0166.2169.4170.9

139.0156.4172.6162.7186.2193.3

171.5182.5193.4197.3200.6200.1

164.7164.0

164.4164.0

139.5150.5163.4167.3170.6170.1

140.4156.3171.6164.3180.1199.2

174.5185.1193.2199.6203.8203,8

165.9166.8

165.2185.7

142.5153.1161.8168.6174.6174.6

138.1156.9171.0160.61B8,319B.2

170.6163.0194.2199.6203.2205.0

166.4164.5

167.0185.2

138.8151.0162.2188.B173.4176.0


1.36 1.72 1.6B0.80 1.01 2.32

1.40 1.07 2.842.69 1.64 2.12

0.71 0.61 1.020.93 0.72 0.96

1.27 1.292.06 1.04

1.93 1.381.82 2.28

0.83 0.661.04 0.62

140.6155.6172.3181.9188.4192.B

173.51B2.5194.919B.7201.6207.0

167.1186,5

167.3185,4

141.5150.5162.9166.4171.6179.0

1.761.36

0.661.07

0.660.66

139.4156.6173.2162.918B.4194.5

171.6163.3194.7199.2202.9204.9

166.0186.0

165.B186.1

139.B151.3162.7169.2172.9175.9

1.7a1.62

2.431.71

1.010.92

142.4 139.9156.2 157.3166.5 166.5174.B 170.5176.2 177.7183.4 -

168.6 166.3175.7 173.8162.7 181.71B3.7 1B7.4192.0 160.0192.0 192.0

157.7 157.2174.5 171.7

167.4 157.7173.4 172.4

136.6 135.2142.7 140.9150.7 149.7151.7 155.4160.0 148.0160.0 160.0

1.14 1.354.36 -

1.40 1.1196.00

1.13 1.040.74 1.04

140.7164.9167.4175.7176.9185.4

166.5174.6179.0188.61s9.1182.0

15B.5172.1

158.7172.9

135.2141.6147.0166.6157.1160.0

1.254.30

1.39135.76

0.9B0.77

141.8154.B168.8176.6177.0185.7

167.2175.2164.41B5.6184.0192.0

156,7173.2

158.2172.6

135.6142.2162.4153.6152.0160.0

2.1041 .5Q

1.7474.36

1.021.19

73

Table 10. Mean bone-specific skeletal ag+mforth.g31 individual hand.wrist bones of youth$by ~ogmphlc region, chronologiml aWlnyeam atltibltihtiy, sndmx, with wlwtdstandard errors: United States, 1966-1970-Con.

Adducmr sesamoid i Flexor sesamoid I Proximal nhalsmx 1Standard of reference,sex, and chronological

age at last birthdayMfd-west

North-.

eastMid.

South westNorth- Mid-

west east westSouth west

-r4unh- M1d-Mst Wt South I wwt

Male standard

BOYS:12 yearn.,,,,., .... ...... .........13 years.,.., .... ......... .........14 years ........ ....................15 years ..... ....... ...............16 yen~ ...... .. ...................17 years ...........................

Girlx12 years ................ .......... .13 yews ........ .. ... .. ............14 years .. .... .. .... ...............15 years .. ...... ...................16 yearn. . .........................17 years ...........................

Actual Vahl@S:BOYS1217 yOWS.. ...... .. ...Girls 12-17 yaws .... ...... ....

ExPccted VahlR5:Boys 12-17 years .............Girls 12-17 years..............

Female equivalent

Girl*12 Vows...............,,., ........13 y80m ........... ... .. .. ... ......14 years ........ .... ...... .........15 years ...........................16 years .........................”17 years ...... .....................

Male standard

Boys:12 years ...........................17 years........................,..

Girls:12 years ............ .............. .17 yearn .............. ... .... .... .

60y5 12-17 years. ... .... ...........Girls 12-17 years .......... .........

Meen skeletal age in months

141,3 140.41E8.6 166.4172.3 173.71s1.5 183.7156,6 1s4.4190.6 196.6

139.3158.5170,91SO.51S7.6197.4

159.2165.6170.1175.8177.7lS1.B

169.6175.7177.7178.9180.7178.8

Isa.s173.6

16s.3173.6

137.6143.7145.7146.9148.7146.S

1.m70.=

0.8911,53

0.530.3B

159.9165.3170.4173.6176.7182.0

16B.9173.21s1.1177.4184.01B6.9

16S.4173.3

16S.5173.8

136.9141.2149.1145.4162.0154.9

1.4596.00

0.9072.43

0.960.86

159.1164.0170.0175.4174.6182.1

171,4175.9177.5185.41s1.s187.3

16S.4175.0

169.0173.7

139.4143.9145.5153.4149.s155.6

0.742.76

1.2359.34

0.450.74

160.4163.8170.8175..!179.C164.3

169.6173.4179.8130.5176.3165.2

169.3173.4

168.0173.7

137.5141.4147.814s.5146.3153.2

0.962.17

1.3471.77

0.610.80

164.3171.7171.7175.4177.0184.7

172.0176.7179.41SO.5185.B167,0

172.2176.0

171.7175.9

140.0144.7147.4148.5153.s155.0

1,0292.77

1.0759.65

0.580.85

166.2lL%C171.1174.3176.6192,0

170.6175.91s3.0179.51s6.6186.2

171.1175.2

171.7175.6

136.6143.8151.0147.5153.6154.2

1.49135.76

0.B772.20

0.920.81

154.3168.5172.6175.6175.6184.2

173.4175.1179.0164.1187.0192.0

172.5175.s

172.5175.4

141.4143.1147.0152.1155.0161.0

165.9165.5172.5176.S179.2186.1

172.7175.5179.4182.017s.9189.6

172.7175.6

172.4175.8

140.7143.5147.4150.0146.91=.s

141.3157.4172.S185.918S.0188.5

176.0186.2194.9203.4207.6208.5

165.21S7.2

164.5186.3

143.0154.2164.9174.4179.6162.5

139.1158.5171.81BO.91BS.Smo.z

173.61S6.1194.6202.6207.2207.2

165.61s5.7

166.1186.0

140.6154.1164.6173.6179.2179.2

141.7155.8172.81S1.61s7.4193.3

176.41s4.5195.3ml.7204.2205.3

166.11S5.6

166.B185.3

143.4152.5165.3172.7176.4177.3

2.011.29

1.121.55

0.96Om

140.7166,0173.3163.8188.120Q.2

174.2162.5197.4204.B205.7ms.5

165.9165.1

165.3185.6

141,2150.5167.4176.6177.71s1.0

141.81!%1172.3184.s1B7.B188.4

176.5165.2193,218B.92C4.O2C4.O

164.61S6.6

163,9184.5

143.6152.4163.1168.9174.0174.0

174.2 175.7 174.31S3.6 184.1 182.7191.3 193.4 104.6188.9 196.1 200.2200.5 201.1 2W,7m2.6 -232.0 204.0

165,4 166,0 164.6184.2 183.9 183.6

141.2 I 142.7 I 141.3160.8 161.1 160,41W.6 163.2 163.6168.9 16s.1 170,2170.6 171.1 170.7172.6 172.0 174,0


0.783.22

1.542.s1

1.62 1.112.05 2.19

2.55 1.281.11 -

1.16 0.861.12 1.28

1.56 1.67 1.381.66 1.91 2.09

1.072.36

1.353.s3

1.233.13

0.881.04

0.69135.76

1.3573.W

1.720.82

1.11 2.IWR 1.49 -

0,86 1.04 0.971.17 0,46 0,90

0.520.6s

1.050.69

0.611.56

74

Table 10, Mem bone.meclfic skeletal sues for the 31 Individual hand-wrist bones of vouths bv aeow.mhlc reoion, chronological age in vears at last birthdav, and sex, with selected

Standard of reference,sex, and chronological

ago at last birthday

s

Proximal phalanx III

lard errors: Un;ted Stat&,-19%1970 -~on~

Proximal phalanx IV I Proximal phalanx V I Middle phalanx II

EEEENorth-east

North- Mid-South West

North- Mid-east west east west South I West

I

North- Mid- 1Southeast west I West

Male standard

BOYS:12 years.,...,, ..... ................. ..13 years........... .... ................t4 years., ................ .............15yeam.,..,, .... .. .. .... .......... ...16 vefl~ ......... .... .... ........... ..17 veals .. .... ... ......... ............ .

Girls:12 Veal ................. ... ...........13 veals .......................... ... ..14 years...................... .........15ve8r\ ................ ...... .. .. ... ..16 years., .............................17vears .. .............................

Actual Vahlf!s:BOW 12.17 veam .... .... .. .......Girls 1217 vears .. ....... .... ....

Expected values:BOVS12.17 years ............ .....Girls 1247 years .................

Female equivalent

Girl$:12 years...,.,,,,,, .... ... ........<....13 years., ...................... .......14 veals.,..,., . .. .. ...................15ymws.,,,........................ ...16 veals ...... .. .................... .. .17vears.,,, .. .........................

Male standard

BOW:t2 years, .. ............................17 veamr.,,.., ................ ...... ..

Girls:12 vets ........... ....................17 veals.., ................ .... ........

SoVs 12.17 years .............. ........Girls 12.17 veals .......................


141.9158.2172.3185.1186.8197.9

176.8184.7193.6199.4204.0204.0

164.6166.0

164.01S5.2

144.9152,7163.6169.6176.0176.0

1.112.8s

1.60

0.961.12

139.6156.6171.3181.1167.7197.0

174,6183.6192.3199.1201.5202.4

165.1183.9

165.71S4.6

143.6151.6162.3169.1172.5173.4

1.611,41

1.053.10

0.s4107

141.3157.0172.6161.5186.0191.3

176.0184.2194.519s.9201.0204.0

165.6185.0

166.2184.5

144.5152.2t 84.5168.9172.0176.0

1.651.84

1.10

0.990.46

140.6166.8t 73.4183.6166.1197.4

174.31s3.4194.1200.4203.0204.0

165.4183.6

164.8184.2

143.3151.4164.1171.4174.0176.0

141.6158.3172.4185.1167.4197.5

177.4185.5193.4199.5204.0203.7

164.6186.5

163,S185.4

145.4153.5163.4170.0176.0t 75.4

139.3158.6171.2160.9167.519s.0

176.0163.6192.3198.6201.7202.6

164.8184.2

165.4164.9

144.0151 .s162.3168.6172.7173.8

1.632.37

1.071.64

0.670.93

141.6156.9172.9161.1166.2180.7

176.5184.8194.2198.6201.3201.7

165.51S5.2

165.0164.6

144.s152.S164.2166.s172.3172.7

140.4158.3173.91S4.0167.3195.4

174.6183.4194.1200.1203.2204.0

165.31s3.s

164.7184.4

143.5151.4164.1171.1174.4176.0

142.0158.2172.4185.3187.5196.5

177.5t 65.5193.3196.8204.0204.0

164.6186.4

163.S1S5.4

145.5153.5162.3166.6174.0174.0

139.6158.7171.3161.2187.5198.6

175.1184.6191.6196.9200.9202.7

166.01S4.2

165.5184.8

143.1162.6160.6168.6171.s173.4

141.8157.1172.4180.8186.4190.7

176.6184.2194.0201.5201.4m4.o

165.318S.3

165.9184.S

144,6152.2163.0172.5172.4174.0

1.712.03

1.04

1.010.53

140.6153.2173.41636165.9195.9

174.71S2.9194.8201.0203.0204.0

165.0184.0

164.7184.6

142.7150.9163.8172.0173.5174.0

142.6158.6172.1182.6186.6196.6

177.0185.3193.4188.7203.6204.0

164.5165.9

163.9184.s

145.0153.3163.4168.4174.5175.0

140.1158.5171.3160.1188.2197.0

174.31S4.7191.4199.6201.0201.3

165.3163.0

165.91S3.6

142,3152.7160.4170.4171.0171.3

141.9156.4172.3161.9185.6191.3

176.2184.4192.9199.2201.3ml.3

165.6164.8

186.4184.5

144,2152.4162.6170.1171.3171.3

142.1.158.3173.6183.3167.6195.6

174.2182.7193.0200.0203.1204.0

165.S1S2.9

166.0183.7

142.21EQ.7183.0170.5174.1175.0

Standard error of the mea”

1.24 1.112.52 2.S6

2.59 1.180.25

1.14 1.020.79 t .08

1.74 1.351.91 1.96

1.16 2.601.71 ‘-

0.94 1.160.47 0.93

1.402.08

1.261.S6

1.36 1.81 1.172.35 1.0s 1.64

1.07 1.39 2.542.61 1.91 .

1.17 1.01 1.060.73 0.55 1.37

1.202.95

1.14

0.921.2s

1.541.80

1.211.95

0.661.1s

2.47 1.05

1.291.05

0.771.21

75

Table 10. Mean bone-specific skeletal ages forthe31 individual handwrist bones ofyouths bygeqraphic region, chronol~ical awin yeamat Iratbirthdav,an dsex.withadaetsdw

Middle pha[mx Ill

dard errors: United States, 1966-1970 –Con.

Middle phalanx IV I Middle ianx V

z

South West

Distal nhalmx IStandard of reference,sex, and chronological

age at last birthday

Male standard

Boys:12 years... .... ...... ... ... ...... ...13 years.................. ... ...... ...14 years................... ...........15 years., ....... .. .. ..... ............16 years........... .... ...............17years...... ..... ...................

Girls:12 years... ............................13 years... ................ ............14 years....................... ........15 years., .............................16 years................ ... .... ........17 years...............................

Actual values:Boys 12-17 year. .... ............Girls 12-17 years ................

Expected values:Boys 12.17 years .................Girls 12-17 years ................

Female equivalent

Girls:12 years............ ....... ............13 years.............. .. .. .............14 years............ ...................15 years.................. .............16 years... ... .. .................... ...17 years.... .. .. .......................

Male standard

Boys:12 years..................... .. ........17 years............... ... .............

Girls:12 years........... ....................17 years... ............................

Boys 12.17 yews ................... ...Girls 12-17years.............. ........ .

TNonh- Mid.east west 1Mid.

WstSouth

*Northeast

141.715s.3172.3163.2187.6I 97.8

176.S1S6.3193.818B.6203.4204.0

164.B1B6.7

164.11S5.4

144.8154.3162.8169.2174.4175.0

North watt

141.0155.716a.4177.6161.416B.B

171.81El .0183.81B9.2189.41B9.9

169.7179.6

159.0178,5

139.B149.0151.4156,4158.8158.6


142.4158.8172.41B3.8187.0187.B

177.01B5.8194.0196.4203.4204.0

165.2166.6

164.6185.4

145.0153.B163.0168.8174.4175.0

1.271.63

1.03—

0.681.26

140.2158.5171.4lBO.O18B.O197.3

174.5184.5191.6198.5199.7201.3

165.51B3.3

166.21S4.O

141.6152.5160.6170.5170.7172.3

141.7156.6172.6162.2186.4182.1

176.51B4.B193.8196.9201.3201.6

166.31S5.4

166.9164.9

144.5152.6162.8169.8172.3172.6

142.1158.4173.5184,2167.4185.5

174.4183.1194.1199.2202.9204.0

166.21B3.3

165.4184.0

141.4151.1163.1170.2173.9175.0

139.715a.o171.4180.0187.9196.6

174.21B4.O191.8199.2201.4201.7

165.2163.2

165.8164,0

141.2152.0160.9170.2172.4172.7

1.362.14

1.141.97

0.950.76

141.5156.0172.2182.01S5.6192.1

176.1184.B193.2188.6201.1201.3

166.6165.0

166.4184.7

144.1152.B162.2169.2172.1172.3

141.0158.1173.5163.9166.9195.0

174.2183.5193.B199.0202.8204.0

165.6183.4

165.o184.1

141.2151.5162.8170.0173.9175.0

142.1158.5172.3183.11S7.O197.3

176.B185.4192.2198.5203.1204.0

164.5185,B

163.B184.8

144.8153.4161.4168.5173.1174.0

139.B15B.O171,2180.1187.5187.0

174.0IB4.8190.9199.1201.2201.7

165.1182.6

165.B183.4

142.0152.6158.9169.1171.2171.7

141.B155.9172.0181.6185.7180.2

175.71B4.5193.2198.1200.7201.3

165.6184.5

166.4184.2

143.7152.5163.2168.1170.7171.3

141.4158.3173.3164.3167.9194.9

176.0181.7194.2198.8203.2204.0

165.6182.7

164.9183.2

143.0148.7154.2168.8173.2174.0

138.4156.6166.8173.8179.2186.6

170,5177.5lB1.6191.0188.01B6.O

158.8176.1

159.6176.6

136.5145.5149.5161.0157.0153.0

140.7154,2168.5175.7177.61B4.6

171.2178.71B3.41B6.8187.21B6.O

159.3177,1

169.6177,1

139.2146.7161.2167.8154.6153.0

1.662.49

1.29

0.770.6B

139.6156.6169.8176.7179.8186.8

170.1176.4184.8191.0191.0186.0

160.1176.9

169.6176,6

138.1144,4161.9161.0161.0163.0

1.492.02

2,2441,69

0.971,09

Standard errorof the mean

1.432.06

1.781.02

1.13 1.231.34 1.86

2,41 1.18. -

1.12 0.711.42 1.28

1.421.70

1.211.95

1.40 1.5a2.04 0.94

1.19 1.511.97 1.91

1.02 0.970.85 0.51

1.32 1.23 1.331.50 2.36 2.51

2.50 1.55 1.202.44 -

1.16 0.83 0.971.50 0.77 0.86

1.750.94

1.371.91

1.010.50 I

1.05 1.272.61 1.69

1.08 1.100.71 0.47,

2.47

1.191.44

1.21

O.BO1.20

76

Table 10. Moan bcme-speclflc skeletal ages forthe31 individual hand++rist bcmesof youths bygeographic region, chronological age in yeamat Iastbirthday, andsex, with selwtedstandard errors: United States, 1966-1970-Con.

Distal phalanx III I Oistal phalanx IV I Distal% halanx VDistal phalmx 1IStandard of reference,sex, and chronological

age st last birthday

Male standard

Mi&-West

Umth-east

Mid-South I North-

Westwest east

Nonh- Mid-east south West

west


Boys:12 YearI ...............................13 years........ .......................14 years . ................ .............16 years................ ...............16 years................. ... ...........17 yenrt ........ .. .... .............. ...

138.6156.8167.1173.5178.3184.3

169.9175.5160.4185.7186.0165.7

159.0174.3

159.8174.9

137.9142.6146.4153.7154.0153.7

1.331.41

1.180.45

0.740.s3

140.8155.0169.7174.3176.9180.8

171.0176.8179.8185.S186.0186.0

159.8175.5

159.9175.4

139.0143.8147.6153.8t 54.0154.0

140.0166.6169.2176.1179.0183.4

169.2176.3162.01S5.8186.0186.0

159.6174.2

159.2174.8

137.2143.3150.0153.8154.0154.0

140.4154.8169.1175.3177.3184.5

171.5179.2183.718s.6187.5186.0

159.9177.4

160.3177.2

139.5146.4151.7156.6155.5154.C

140.1156.7169.5176.8179.8787.2

170.0176.8185.2190,9191.0166.0

160.4176.0

159.6176.8

136.0144.6153.2160.7161.0164.0

141.2156.4168.9177.6181.1165.7

172.3181.31S4.2189.3169.E190.C

160.2179.6

159.:178.1

140.?149.2152.1158.:158.!159.(

136.4156.1167.1173.6178.6186.0

169.8176.7181.5191.0188.5166.0

156.9175.6

159.9176.6

137.6144.7149.5161.0157.0153.0

1.282.36

1.07

0.730.99

140.4154.9169.2175.0176.4184.3

171.3179.0183.5188.7187.5186.0

159.7177.2

160.0176.9

139.3147.0151.5157.4155.5153.0

140.0156.7169.2176.4178.S187.0

169.6176.8185.1190.9191.0186.0

160.1175.8

159.6176.6

137.6144.8152.6150.8161.0153.0

141.6156.0169.0176.2178.7163.9

172.0177.6181.7185.7186.0186.0

159.3177.1

158.7176.0

140.0145.6149.7152.8152.0153.0

138.8156.8167.6173.8178.1184.3

169.9175.5160.1185.&166.C165,E

159.2174.2

159.s174.5

137.:143.!146.1152.<153.(152.$

140.7155.1169.7174.2176.9181.1

170.9176.9179.6185.8186.0186.0

159.7175.4

159.9175.2

138.9144.9147.6152.9153.0153.0

1.460.91

1.36—

0.660.69

140.2156.6169.0176.3177.8184.1

169.3176.2161.9185.8166.0186.0

158.4174.1

159.0174.6

137.3144.2149.9152.9153.0153.0

1.381.02

1.73—

1.101.27

141.6156.1158.6176.4178.5183.7

172.2176.2181.8185.6166.0166.0

159.4177.3

158.7176.0

139.6145.2149.6153.6154.015+?.0

1.031.43

1.62—

0.980.79

141.1156.6166.9177.9181.2165.8

172.4181.6184.4189.3169.3190.2

160.2179.8

159.3176.4

140.4149.6152.4157.3157.3158.6

138.5158.8167.6173.6178.4186.2

170.3177.6161,8191,0188.2166.0

159.0176.1

169.9176.9

138.3145.3149.6161.0166.2154.0

Girls:

12 years...... .. ................ ......13 years. ..............................14 yeer5, .............................16 years..............................16 years... .... .......................17 yearn ....... .......................

Actual Vdlle$:BOYS12-17 Wars. . .. ............Girls 12.17 years .... ............

Expacted VOhlES:

80Y$ 12.17 veals ... .............Girls 12.17 years ................

Femaln equivalent

Glrk:12 year: ... ........... .............. ..13 years............ ................ ..14 yem’s... .. ............... ..........16 yam. ................ .............16 years ... ..........................17 years...... ........................

Male ttendard Standard error of the mean

11.00 1.381.32 1.60

1.49 1.18— 0.60

0.96 0.830.78 0.90

80VS:12 years................ ....... ........17years .... .. ............... .. .... ....

1.1.47 1.101.62 3.53

2.01 1.832.46

1.11 1.010.96 0.73 1-

1.49 1.451.04 1.13

1.29 1.70

0.62 1.180.66 1.28

1.09.1.26 1.462.85 2.28 1.45

1.82 1.08 1.322.60 – -

1.421.66

1.441.63

1.20

0.620.72

—

Girls:12 years... ........................ ....17vears ....... ........................

1.65

1.040.91&lE-k80Y1 12.17 years ....... ...............

Glrh 12.17 years........... ............

77

Table 11. Mean bOne-specific skeletal ages forselected hand.wristb0nesof youths byannual family income, chronological ageatlast titihday, andsex, with selected standarderrors: United States, 1966-1970

IMetacarpal III I Metacarpal V I F’roxirnalphalanx lll



Male standard’

Boys:12 years .. ...~.. .. ... ... .. ... .. .... .. ....~ ... .. ..13 years ... .. .. .. .... ... .. ... ... ... .. ... .... .. .. ..14 years ... ... .. ... .. ... .. .... .. .. .... .. .. .... .. ..15years ... ... ... .. .. .... . ... .... ... ... .. .. .. .. . ..16 years .. ... ... ... ... ... ... .. .. .... .. .... .. ... .. .17 years ... ... .. .... .. ... . .... ... ... .. ... ... ... .. .

Girls12years .. . .... ... .. .. .... .. ... ... .... .. .. .... .. ...13 years .. .. .. ... .... .. ... ... ... .... . ... ... ... .. ...14 years ... .. .. .. .. .. .. .... .. .. .... .. .... ... ... .. ..15 years .. .. .... . ... .. .. ... ... . ..... .. ... ... ... .. ..16 years .. .... .. .... . ... .... .. ... ... .. ... ... ... ... .17 years ... ... .. .... .. ... .. ... .. .... ... ... ... .. .. ..

Actual values:BOYS 12-17 years ..... .. ... ... ... ... .. ... ... ..Girls 12-17 years ... .. ... .. .. ... .... .. ... ... ..

Expected values:Boys 12-17 years .... ... . .... ... .. ... .. ... ... .Girls 12-17 years .... .. ... .. ... ... ... .... . ... .

Female equivalent

Girls:12 years..., . ... ... ... .. ... ... .. ... ... ... ... .. .... .13 ye.9rs,,... .. . ... ... ... .... .. .. ... ... .. .... .. .. ..14 years,., .... ... .. ... ... .. .. .. .. ... .. ... ... .. ... .16 years .. ... .. .. .... .. ... .. ... .. .... . .... ... .. .. ..16 years.,, .. .. ... .... . ... .. ... ... ... ... ... .. ... .. .17 years .. .. .. .. .. .. .... .. .. ... .. .... .. .... .. ... .. .

Male standard

Boys 12-17 years .. ... .. ... ... ... ... .. ... ... .. .. .. .Girls 12-17 years .... .. ... ... .. .. .... .. ... .. ... .... .

Lessthan

$5,00(

140.0153.1167.8172.7176.2185.2

165.7174.61S0.6190.0171.0

156.7171.4

157.7172.6

134.8141.614S.6160.013s.0

$5,000-$9,999

138.1158.7188.6174.5175.6186.3

166.3174.2180.0189.2185.0192.0

158.3171.8

156.5172.7

135.3141.2148.0157.6153.0162.0

$10,000or

more

4

142.0154.2167.4176.11s0.2188.1

170.0175.6185.8182.8189.6191.1

157.6174.8

157.1172.6

137.0142.6153.8150.8158.8161.1

ILessthan

$5,00[

138.4154.8171.8180.0185.B193.0

172.81s2.2192.919s.0200.8199.3

165.1183.5

166.1183.4

140.9150.2161.916S.0170.8169.3

$5000- $10,000 Less $10,000 Less

$9;999 ‘r ~:h:~ Y9;Y9: ~:remore , $?%0 ~~


137.2157.5171.9161.7187.2194.5

171.4183.0190.6186.6200.1202.2

164.6183.2

164.6183.8

139.4151.0159.6166.6170.1172,2

140.8155.4171.3182.8189.0187.1

173.0182.4184.6188.2199.0198.4

165.1183.8

164.5183.4

141.0150.4163.6166.2169.1168.4

138.5165.2172.61S0.6187.4193.B

173.51S2.5194.7200.9204.5203.0

166.2185.3

167.21B5.O

141.5150.5163.4170.9175.5173.0

137.7158.0171.8181.8189.2196.7

171.4183.8192.3198.4202.6208.1

166.0185.1

166.1185.8

139.4151.8161.2167.8172.6177.1

Standard error of the mean .

141.2155.6171.61B3.7180.4197.4

172.7183.1196.1199.8202.4203.6

156.1186.1

165.6185.7

140.7151.1165.1168.8172.4173.6

0.820.73

138.1158.9172.6180.71S6.1193.5

176.1183.3193.4201.0202.6284.0

164.9164.6

166.1184.6

144.6151.3163.4172.0173.6176.0

139.8159.5172.1181.9187.5195.8

174.4184.0190.9188,3203.6204.0

164,8183.9

164.7184.7

143.4152.0180.8169.6175.2176.0

1.21

II

0.530.68 0.57

$10,000or

more

142.0157.9172.5184.5188.1200.3

175.9164.0195.8198.9201.8202.1

165.5165.5

164,S165.0

144.4152.0165.8168.9172.8173.1

0.620.73

78

Tabla 11, Mean bone-specific skeletal ages for selected hand-wrist bones of youths by annual family income, chronological age at last birthday, and sex, with selected standard



Male stendard

Boyc12v0ars.,.., ... . ... .... .. ... ... ... ... .. ... ... .... .13 yaars ....l...,,,, . . ... .... .. ... ... .... .. .. ... ...14 years, . .. .... .. .. .... .. .. ... .. ... .. . ... ....15years .... .. ... .... .. ... .... . ... ... .. .... .. .. ....16 year . ... ... ... ... .. .. .... ... .. .... .. ... ...17yeers .... .. ... ... .. .. .. .. .. .... .. ... ... ... .. ... .

Girls:12yeers,..i..,o,, .. .. .. ... ...o.... .. ... ... ... ... ..13 year,...,,.,..,... !,..,., ... .. ... .. .. .... .14 years ... ... ..i .. ... .. ... ... .. .. .. .. .. .. ... ... ...16ynars ..... .. .. .... .. .. .. .... .. ... . .... .. .. .... ..16 yaers .. .... .. .... .. .. .. .. .. .. .... .. .. .. .. .. .. ...17years .. .... .. .... ... ... .. .. .. .. .. .. .... .. ... .. ..

Actual values:BOYS 12.17 years ..... .. .. ... ... .. .... .. .... ..Girls 12.17 years .... ... .. .... .. .. .... .. .. ....

Expectad VdURS:

Boys 12.17 years .... ... ... .... ... .. ... ... .. ..Girls 12.17 yeers ... . .. .. .... .. .. .. .. .... .. .. .

Female equivalent

Girls:12y0ars .... ... .. ... . .... .. .. .. .. .. ... .... .. ... ... .13 yeers,,.o,.,.., ... .. .... .. ..l ... ... .. .. .... ... . .14 yaars .... ... ... .. ... .. .. ....o.... .. .... . .... . ...16 years ..... ... .. ... .... .. ... ... ... ... ... ... ... .. .16 veals,., .. .. .... .... .. .. .... ... .. .. .... .. ..17 years,..,,, . .. ... ... .... .... .. ... .. ... ... ... ... .

Male stenderd

Boys 12-17 years ,,,,,.,,,,.,,.,...,.,..,..,.,,,..,Girls 12-17 years.,,.,, .. .. .. ... .... .. .. .... . .. . ... .

errors: United States, 1966-1 970-Con.

Proximal phalanx IV 1 Middle phalanx V I Radius I Ulna

139.2156.8172.5180.91s5.3193.1

176.61S4.O193.2201.0202.6201.5

164.6185.1

165.61S4.8

144.8152.0163.2172.0173.6172.5

1.220.68

139.5159.4172.41S2.O168.5195.2

174.51s4.2191.0198.8203.6204.0

184.8184.1

164.6184.8

143.5152.2161.0168.8175.2176.0

141.8157.4173.01s4.2167.3200.0

176.61SS.6194.8198.7201.8202.5

165.2185.6

164.5185.3

144.8151.6164.S168.7172.8173.5

140.6156.8172.1179.9186.5191.9

175.9183.4192.1198.2201.6202.5

164.S183.8

166.1183.9

143.9151.4161.2168.2171.6172.5

$5000- $10,000 Less $10,000 Less $10,000

$J,999 0’$17ano ~&&~ or

more , more~:;;. ~@j or

more

140.0159.2172.2162,2187.4185.9

174.2183.8192.1199.4202.6204.0

166.2183.7

165.0184.2

142.2151.8161.2169.4172.6174.0


142.3157.4171.7182.7187.6198.4

176.1184.0192.9t98.1202.0202.7

164.9180.4

164.5184.0

144.1152.0162.6168.1172.0172.7

138.9156.0173.8186.0196.1204.9

175.41S4.4197.2208.6214.7216.3

174.6196.6

175.7196.6

143.4152.4167.2182.2191.4193.3

138.8158.6174.11S6.1196.2207.2

173.01S6.2196.9208.7214.1218.2

174.8197.0

174.8197.1

141.0154.2166.9182.4190.2195.2


0.530.57 I :21 :::1 :::

140.5155.9172.21SS.2200.220S.7

173.2185.7199.6208.0214.8215.9

175.6199.2

175.0199.2

143.2153.7169.6181.0191.6192.9

. . .

. . .

139.5166.0173.5183.7194.0200.5

174.8184.5195.5203.5206.9205.8

172.5190.4

173.2190.6

142.8152.5165.5174.0179.9178.6

. .

138.5158.0173.8185.7193.4202.5

172.4185.6195.0204.2205.3209.4

172.0190.7

171.9191.1

140.4153.6165.0175.4177.61S2.4

. . .

. . .

140.7155.3171.7187.7196.6202.9

172.9185.1199.1203.1206.7208.5

172.3193.0

172.0192.6

140.9153.1170.1173.2179.7181.5

. . .

. . .

79

Table 11. Mean bone-specific skeletal ages for selected hand-wrist bones of youths by annual family incomerrors: United States, 1966-1 970–Ccm

Capitate!

HamateStandard of reference. t , 1 rsex, and chronological Less $10,000 Less $10,000

age at last birthday~j’~o %:9: ‘r &hym %,:E ‘rmore , more

chronological age at last birthday, and sax, with seloctod standard

Lunate!

Smphoid1 I 1

Less $10,000 Lass $10,000

~;:m %%- ~;re &o %% 0’more

Male standard Mean skeletal age in months

Boy%12years ... .... .. .. ... .. .... ... .. .. .. .. .. ... ... ... .13 veals ..... .... .. .. .... . ... ... ... ... .. ... ...14 iears ... .. ... .. ... ... .. .... .. ... ... .. ... ... ... ..15years .... .. ... .. .. ... .. ... ... .... .. ... .. ... .. ...16yeam ... .. .. .. ... .. ... .. .. ... ... .. .... .. .... .. ..17 years ... .. .. .... .. .... .. ... .. ... .. .. .. .. ... ... ..

Girls:12years ... .. .... .. .. ... ... ... .. .. .... ... .. ... ... ..13 years..., . ... .. .... .. .. .... .. ... .. .... .. ... .. ...14years ... .. .. ... ... .. .... .. .. ... ... .... .. ... .. ...15years .... ... ... ... .. ... .. ... ... ... .. ... .... .. .. .16 years ..... .. .. .... .. .. .. .. .. ... ... ... .. ... .... ..17vears ..... .. .. .. .. .. .. ... ... ... ... .. .... . ... ... .

Actual VdUeS:

BOYS 12-17 years .... .. ... ... .. .... .. .. ... .. ..Girls 12-17 yeara ... ... . ... ... .. ... ... ... ... ..

Expectad val uexBoys 12-17 years .. ... .... .. ... .. ... .. ... ... ..Girls 12-17 years .. ... .. .... .. .... .. .. ... .. ...

Female equivalent

Male standard

Boys 12-17 yeara ... ... .. ... ... .. ... .. .... .. ... ... .Girls 12-17 years ... ... .. .... ... .. ... .. ... ... ... ... .

139.9153.716B.2173.0176.31B3.B

166.8175.7180.7190.0179.0192.0

157.1172.7

158.2173.5

135.4143.714B.7159.0147.0162.0

. . .

. . .

139.1157.5156.8174.9176.1185.9

167.1175.2180.2188.4184.0192.0

156.7172.5

156.9173.4

135.2143.214B.2157.4152.0162.0

. . .. . . I

142.7155.1168.1176.1179.61B7.6

169.9176.31S6.0164.3190.3191.3

15B,3175.1

157.6173.4

137.9144.3154.0152.3159.6161.3

141.4154.6168.7173.5177.7164.7

168.0175.8181.4190.0171.0192.0

157,8173.1

158,B173.9

136.0143.8149.4159.0139.0162.0

. . . . . .

. . . . . .

140.715B.4167.9175,6177.1186.2

167.6175.9180.2189.7184.0192.0

157.7172.9

157.6174.0

135.6143.9146.2158.7152.0162.0

143.1155.5167.9176.B180.4187.9

171.5177.2183.0183.8190.3131.3

158.3176,1

158.1174.2

139.5145.2151.0151.8159.6161.3

139.9154.1167.4172.3176.01B5.1

166,0175.0179.8190.0192.0

158.8171.6

157.7172.3

135.0142.0147.6159.0161.0

13B.7156.2167.0173.9175.6185.5

166.0174.0179.4189.1164.0192.0

155.9171.4

156,3172.6

135.0141.0147.415B.1152.0161.0

142.1154.7187.6176.1179.7186.2

169.6175.6185.7163.1188.7190.2

157.8174.8

157.1172.9

137.6142.6153.7151.1157.7159.2

Standard errm of the mean

138,4153.1187.2172.7176.6182.7

165.7174.7179.3190.0190.6

166.0171.6

157.0172.1

733.8142.7147.3159.0159.6

137.6155.4166,6174.7175,61B6.3

165.1173.8179.6168.6184,0192.0

155.4171.0

155.6172,2

133.6141.B147.6157.6152.0161.0

:::1 :::1

140.2154,0167,3176.9179.4190.5

169.4175.6186.3182.11BB,9169.9

167.1174.9

166.6172.7

137.B143.6163.3160.1157.9166.8

. . .

. . .

80

Table 11. Mean bona-specific skeletal ages for selected hand-wrist bones of youths by annual family income, chronological age at last birthday, and sex, with aalacted standard

errors: United States, 1966-1 970 —COn.

Standard of referenca,sax, and chronological


Male standard

BOYS:12years .. .. ... .... .. ... ... ... .. ... ... ... ...i .. ....13 years .. .. .. .. .... .. .. ... ... ... ... .. .... ... .. ... .14 years .... .. .... .. .. .... .. .. .. .... ... ... ... .16 year . .... .... . ... .. ... ... .... . ... ... ... ...16 YellrS..., .. .... .. .. ... ... .. ... ... .... . .... ... .. .17years .... ... .. ... ... .. ... ... .. ... .. .... ... ... .. .

Girl&12 years ... ... ... ... .. ... .. .... .. .. ... ... .. ... .....13 years, ... ... ..i .. .. ... .. ... .. ... ... .. ... ... ... ..14 years ... .... .. ... .. ... ... .. .. ... ... ... .. .... ... .16 years.., . ... . .... .. ... .. .. ... ... .. .. .... .. .. ....16 years .... ... . .... ... .. .. ... ... ... .. ... .. .. .... ..17 years .... .. .. .... .. ... .. .... . .... .. .. ... ...

Actual values:Boys 12.17 years ... .. ... ... ... .. .... .. ... ... .Girls 12-17 years ... ... .. .. ... ... .. ... ... ... ..

Expgcted values:

BOYS 12.17 years ..... .. ... .... . ... .. ... .... ..Girls 12-17 years .... .. .... ... .. .. .... .. .. ....

Female equivalent

Girls:12years.. i.. .. ... ... .. ... .. ... .. .. .. .. ... ... .. ... .13 ymrs .. .... ..i ... .. .. ... ... .. .... .. ... ... .. .... .14 years<.. ... .. ... ... ... ... .. .. .... .. .. .... .. ... ..16 years .... ... .. .. ... ... ... .. ... ... ... .. .. .... .. ..16 years.., .. .. .... .. .. .. . ... .. .... ... . ... .... .. .. .17 years .. ... ... ... . ... ... .... .. ... ... ... . ..... .. ..

Male standard

Boys 12.17 years ... .... .. .... . ... .... .. .. .... .. .. .Girls 12-17 years., .. ... .. ... ... ... .. ... ... ... .. ... .

137.7152.2167.5172.4176.4183.5

165.5174.41s0.1191.0191.3

155.7171.5

158.8172.3

134.2141.2148.1159.0159.6

. . .

. . .

$5,000.$9,999

TraDezium I Trapezoid!

Metacarpal I

Lessthan

$5,000

136.6155.7166.2174.5175.8186.1

164.8174.7179.2189.1185.0192.0

155.0171.2

155.3172.4

133.9141.4147.2157.1153.0161.0

,,,. . .

I$10,000 Lessor than

more $5,000

139.7154.2167.5175.9179.8189.2

169.3175,5185.8164.0189.1192.0

156.9174.8

156.1172.7

137.3141.8153.8152.0157.1161.0

138.0152.4167.7172,2176.6183.4

165.4174.9181.3191.0191.3

155.7171.9

157.0172.5

134.2141.9149.3160.0160.3

:::1 :::

$5,000-$10,000 Less $10,000

$9,999 ‘rmore$$:;O :~9-

moreor

I

Mean skeletal aga in months

137.2155.6166.5174.7175.5187.0

165.2174.4179.1189.1185.0192.0

155.4171.2

155.6172.4

134.1141.4146.2157.1153.0161.0

140.2154.3167.7176.0176.9166.4

169.7175.5185.6162.8189.2192.0

157.0174.8

156.4172.6

136.6142.5153.6150.8167.2161.0

13B.O153.9169.4174.7178.8183.0

170.2177.5179.9186.0186.0186.0

160.0175.5

160.8175,5

138.2145.5147.8155.0155.0155.0

137.0156.7169.1176.8177.9183.5

169.5177.1180.3185.2186.0186.0

159.4175.2

159.5175,7

137.5145.114s.3154.2165.0155,0

140.0154.8169.4177.3180.7185.7

171.4177.3183.1184.6184.3186,7

160.2175.9

159.8175.2

139.4145.3152.1153.6153.3154.7

Metacarpal II

137.6154.2171.3180.1187.4193.2

171.9182.4195.5200.3205.6200.9

165.21S4,6

186,2184.4

139.9150.4165.5170.3176.8170.9

136.7157.0171.9181.6187.1196.5

170.9183.8191.3197.8202.5206.7

164.5184.1

164.6184.7

138.9151.8160.3167.8173.0178.7


. . .

Ill... ...... ... ... :::1 :::1 :::1 :::1

140.0164.6171.0164.2189.6200.0

172.4182.7186.0189.1202.8199.6

165.6184.7

164.9184.4

140.4150.7168.0169.1173.6169.6

. . .

. . .

81

Table 11. Mean bone-specific skeletal ages for selected hand-wrist bones of Youths bv annual family income. chronological age at last birthday. and sex, with sekted standarderrors: United States, 1966.1 970 —Ctm.

I , m



Male standard

soys:12 years .. .. ... ... .. ... ... ... .. .. .... .. ... ... .. ... .13 years .. .. .... .. .. ... ... ... .. ... .. ... ... .. .. .... .14 years .. .. .. . ... ... ... .. .. ... ... .... .. .. ... ... .. .15 years .. ... .. .. .... .. ... ... .. ... ... .. .... .. ... ...16 year...,.., .. ... .. ... .. ... ... .. .... ... . ...17 years .. ... .. .. .. .. .. .. ... ... ... ... ... .. ... .. ...

Girls12 years .... ... .. ... .. ... .. ... ... ... ... ... .. ... ... .13 years .. .. ... ... .. ... ... .. ... ... .. ... ... ... ... ...14 years..,.,..,, . ... ... .. .... .. .. .. .. ... .. .. .. .. ..15years .. ... ... .. ... ... .. .... . .... ... .. ... .... .. ..16 years .. .... ... ... .. .. ... ... .. .... ... ... .. ..17 years ... .... . ... .... .. .. .... .. ... .. .... ... .. ... .

Actual values:Soys 12-17 years ... .. .... . ... .... .. .. ... .. ...Girls 12-17 years .. ... . ... .. .. ... ... .. .... . ...

Expected valuas:BOYS 12-17 years .... .. ... ... .. ... .... .. .. .. ..Girls 12.17 years .... .... .. .. .. .... .. .... .. .. .

Female equivalent

Girls:12years ... .... . ... ... ... .. ... .. .... .. ... ... ... .. ..13 years .... .. ... .. .... .. .. .... .. .... .. .. .. .. .. ....14 years ... .... ... .. ... ... .. ... .. .. .. .. .... .. .. ... .15 years ... .... .. .. .. .. ... .. ... .. ... .... . .... .. ... .16 years ... . ... .. ... ... ... .. ... .. ... ... .. .... ... . ..17 years .. ... .. ... .. ... ... .. ... ... ... .. ... .. .... .. .

Male standard

BOYS 12-17 years .. .. .... .. ... .. .... ... ... .. .. ... ..

Girls 12-17 years ... .. ... ... ... .. ... .. ... ... .... .. ..

Metacarpal IV I Pisiform I Adductor sesamoid I Flexor sesamold

Leasthan

$5,000

138.4154.7172.2179.6185.7191.8

172.4181.7192.7198.6201.2200.1

164.8183.6

166.7183.5

140.4149.7162.4168.6171.2170.1

,..,,.

$5,000-$10,000 Less

$9,999 0’than

more $5,000

137.2157.6171.s181.7187.4193.3

171.01s2.s190.8196,3200.0202.7

164.71s3.1

164.6183.7

139.0150.8159.8166.3170.0173.4

140.7155.3171.3182.3188.5196,6

172.51S2.6194.3197.3199.2189.3

164.81B4.O

164.31B3.5

140.5150.6164.3167.3169.2169.3

,..I

.,.... ...

140.5153.5167.8173.1178.3187.2

166.0174.8181.2180.0192.0192.0

158,5172.2

159.3172.9

135.0141.s149.2148.0160.0160.0

$5000- $10,000 I Less $10,000 Less

W;999 0’ ~:h:o fiT9t ~:rethan

more , $5,000


140.5157.5167.0173.7173.21S3,8

166.0173.9180.4189.3188,4192.0

157.3172.3

157.3173.1

135.0140.9148.4157.3156.4160.0

141.0154,8167.4174.7181.0190.4

169.3175.6184.8181.9189.9192.0

157.4174.4

157.5172.6

137.3142.6152.8149.9157.9160.0

15s.4153.9170.2173.4176.1181.3

170.5175.2177.4181.4184.3162.7

16B.2174.0

169.3173.6

138.5143.2145.4149.4152.3132.7

160.6165.6170.5175.6178.3183.9

169.7173.8177.5184.5184.6187.0

168.8173.8

168.5173.8

137.7141.8145.5152.5152.6155.0

159.3184.B170.1174.4180.8187.0

169.3173.51B3.2176.7175.6186.9

168.7173.6

168.6173.9

137.3141.5151.2

144.7143.6154.9

162.9167.9171.6174.0177,3183.2

174.1175.6179.0183.4191.4186.0

171.7176.4

172.6175.6

142.1143.6147.0151.4180.4154.0

I$5,00c-$10,000

$9,989 0’more

165.2170.0171.9175,B175.8184.9

172.1176.3179,11S4.6184,41S8,2

172.1175.7

171,8175.9

140.1143.3147.1152.6152.4157.2


II... ...... ... :::1 :::1 :::1 :::1 :::1 :11

165.6167.1172.0174.91BO.6189,8

170.8176,0184,0177,9179.2189.6

172.0176.3

172.0175.7

138,8144.0152.0146.9147.2158.5

. . .,..

82

.Table 11. Mean bone-specific skeletal ages for selected hand-wrist bones (

Standard of reference,sex and chronological


Male standard

Boys:12 years . .. .... .. .. .. .. ... ... .... .. .. .... .... .. ....13 years.,,,,.,,.,,.,,.,,.,..,..,..,.,,,.,..,,,...,14 years,,., .. ... .... .. ... .... .. ... ... ... ... ... ... .15 years . .. ... ... .... .. ... ... ... ... ... ... .. .... ... .16 years., . .... .. ... ... ... ... ... ... .... . .... .. .... .17 years . ... ... ... ... .. ... .... .. ... .. .... .. .... ... .

Girls:l2years,,,,,.,,,.,.,...,.,..,.....,.,..,..,.....,,13 year,,.,,..., . .... .... . ... .... .... .. ... .. .

14 years,,...,,..., .. ... . .. .. .. ... ... .. ... . .... .. ..16years . ... ... .. ... ... ... ... .. ... ... ... .. .... .. ...16 yearn .... .. ... ... ... ... ... .. ... ... ... .. ... .... .17 years ... .. .... .. ... .... .. ... ... ... ... .. .. .... ...

Actual values:Boys 12-17 years ... .. .... . .. .. .. .... ... .. ....Girls 12-17 vears ... .. ... .... .. .. ... ... ... ... .

Expected values:60vs 12-17 veals . ... ... ... ... ... ... ... .. ... ..Girls 1217 years ..... . .. .. ... ... .... .. ... ... .

Female equivalent

Girls:12 years,,,.,..,,,,,..,,.., ... . ..... ... ... ... .. ... .13 years .. .. ..... .. ... ..i .. ... .... .. ... ... ... .. ....14 years .. .. .. .. .... .. .... ... .... ... .... .. .. .... .. .l6years,.,,..,.,,,,,,,,,.,...,,.,..,.........,....16 year.,,.,, . ... .... ... ... .... ... ... ... ... ..17 years .. .... .. ... ... .... ... ... ... ... ... .. ... ... ..

Male standard

Boys 12-17 veara . ... ... ... .... .. .... .. ... .... .. .. .Girls 12-17 veara ... .. .... ... .. .... ... ... .. .... ... ..

errors

Proximal phalanx I

Lessthan

$5,000

139.5155.9172.4I 80.4188.5195.7

175.7163.7194.2203.1207.5204.5

165.7185.0

166.8165.5

142.7151.7164.2174.1179.5176.0

. . .

. . .

$5,000-$9,999

139.1156.6173.2162.7188.1200.2

173.6184.7

193.8203.4207.0208.7

165.4185.5

165.2166.2

140.6152.7163.8174.4179.0181.4

. . .

. . .

$10,000or

more

142.1157.1172.0164.4166.2201.8

175.718.5.7

197.B204.0204,9207.6

165.5187.1

165.0166.2

142.7153.7167.8175.0176.8179.6

. . .. . .

fouttts bv annual tam!ly income, cnronologlcal age at last mrtrmay, ana sex, wlrn semxed standardhtited States, 1966-1 970–Con.

Proximal phalanx II I Proximal phalanx V I Middle phalanx II

Lessthan

$5,000

138.6156.5172.4180.4186.2193.3

175.3162.8

192.6200.8202.6201.8

164.6183.9

165.9184.1

142.3150.4162.2170.8172.6171.8

. . .. . .

$5,000-$10,000 Less $5000- $10,0+30 Less

$9,999 ~:re$&o $Q’~” :,.

than

$5,000I 1 I 1 1


139.6159.3172.1182.1187.9195.8

174.3183.7

190.4198.8202.4204.0

164.7183.4

164.6164.1

141.3150.6158.4168.6172.4174.0

142.0157.5172.3184.2187.4200.4

175.9163.9195.2196.5201.4202.2

165.2185.1

164.5164.5

142.9150.9164.2168.5171.4172.2

139.5158.7172.8160.6165.6194,1

176.4183.0

193.1202.3202.7204.0

164.8184.6

165.9184.8

144.4151.0162.1173.2173.4174.0

139.6159.5172.5181.6187.9184.6

174.6184.3

190.7199.3203.6204.0

164.5184.3

164.5184.9

142.8152.3158.7169.3173.8174.0


. . .

. . . I :::, .... .... ...

142.4157.4172.1184.2186.6199.9

176.6184.0194.4199.7202.3202.7

165.0185.9

164.4185.4

144.8152.0163.4169.7173.2173.4

140.6155.8172.4178.6186.3193.0

176.3183.8

191.7199.7202.6202.1

165.0184.2

166.2184.2

144.3151.8160.7170.4173.2173.0

I$5 ~o. $10,000$9’,988 ~:re

140.5159.4172.1161.6167.7196.2

174.3183.8

191,6199.5203.2204.0

165.2183.6

165.1184.2

142.3151.8160.6170,2174.2175.0

:::] :::1 :::

143.0157.7172.1183.4188.1198.2

176.1184.0

193,9199.6201.8202.7

165.3184.6

164.6184.3

144.1152.0163.9170.3171.6173.4

. . .

. . .

83

Table 11. Mean bone-specific skeletal ages for selected hand-wrist bones of youths bv annual familv income. chronological age at last birthday, and sex, with selscted standard


8SS at last birthday

Male standard

soys:12 years .. ... .. ... .... .. ... ... ... .. ... .... ... .13 years .. . .... ... ... ... .. .... .. ... ... .... . .. .. ....14 years..., .. .... .. ... .. .... ... ... .. .... .. .... .. ..15 ye.9rs,., .. .... .. ... ... ... ... ... .. ... ... .... .. ...16 years .. .. ... ... ... ... .. .... .. .... .. ... .... .. ... .17 years .. . ... .. .... .. .... ... ... ... ... ... .. .... ... .

Girls:12 years . ... ... ...i .. ... ... ... ... .. . .... .. .... ... ..13 years..., ... .. ... .... ... ... .... ... .... .. ... .. .. .14 years ... ... ... ... .. .... .... .. ... ..... .. ... ... ...15 years .. .... ... .. ... .... .. .... .... .. ... ..... .. .. .16 year.s. ... ... .... ... .. ... .... .... ... .... .. ... ... .17 years... c.. .... ...c...c. ....c.. ... .... .. .... ... .

Actual values:BOYS 12-17 years .... .... ... ... ... .. .... .. ....Girls 12.17 years ... .. .. .. .... ... .... ... ... ...

Expected values:SOYS 12-17 Y13w5.... ... .... ... .... ... ... .... .Girls 12-17 years .. .. ... .... .... ... ... ... .... .

Female equivalent

Girls:12 years ... ... ... ... ... ... ... ... ... ... ... .. .... ... .13 years .. .... .. ... .... ... ... ... ... .. ... ... ... .. ...14 years ... . .... .... .. ... ... .. .... ... .. ... .... .. .. .15 years . ... ... ... ... ... .. .... .. ... .. .... ... ... .. ..16 years . .. ... .... .. ... .. ... ... ... ... ... .. ... ... .. .17 years ... .. ... .. .... ... .. ... ... ... .. ... ... ... .. ..

Male standard

BOYS 12.17 years .. ... ... ... .... ... .. .... ... ... ....Girls 12-17 years .. .... .. .... .. ... .... ... .. ..... ... .

errors: United States, 1966-1970-Con.

Middle phalanx Ill

=

140.9156.0172.51s0.11S6.6193,5

176.51S4.O193.2199.4202.12U1.9

165.61s5.0

166.71s4.s

144.5152.0162.2170.4173.1172.9

. . .

.,.

140.5159.3172.31S2.91s7.3196.S

174.3183.9192,0199,1201.6204.0

165.71s4.0

165.5184.s

[email protected]

. .. . .

142.615s.0172.31S2.71S8.319S.2

176.31s4.7194.2199.3201,5202.7

165.3165.2

164.91S4.5

144,3152.7163.2170.3172,5173.7

Middle phalanx IV

Lassthan

$5,00Q

140.1155.4172.61s0.01s6.6194.0

176.4184.0193.119s.7201.9202,5

165.2184.s

166.31s4.7

144.4152.0162.1169.4172.9173.5

Distal ❑halanx [ I Distal c!halanx II

140.0158.8172.31S2.21S6.9196.1

174.01S3.6190.6199.1203.3204.0

165.21S3.8

165.11S4.6

141.0151.B159.2170.1174.3175,0


141.9157.6171.s183.1188,2197,6

176.01S5.2191.6199.1202.0202.7

165.01s5.4

164.61S4.6

144.0153,2160.6170.1173.0173.7

139.4152.9168.s173.3178.4165.5

170,617s.41s1.2191.01S6.01s9.0

158.6176.6

159.9176.9

136.6146.4149.2161.0153.0158.0

136.5157.416s.0175.3179.81S5.2

168.0177.71s2.11s9.5189.81S7.6

15s.9176.4

159.0177.5

137.0145.7l!W.1159.0159.6155.s

140.9156.1167.9177.5180.7190.6

173.4179.11s6.61%X9190.9180.0

159.s179.2

159.2177.3

141.4147.1153.6160.9160.9148.0

139.0153.6168.3173.5178.0165.4

170.2178.91s1.s191.01ss.0190,2

158.6176.6

160.1177.0

136.2145.9149.8161.0154,015S.6


138.7168.0168.5175.617s.s1s5.3

168.2178.01S2.S1S9,61S7.6187.6

15s,5176,6

169.5177.7

137.2145.6150.s167.5155.6155.6

. . .

. . .

141,3166.1166.s176.9161.7190.5

173.6179.3186.3180.9191.01S6.0

160.3178.3

169,6177.4

141.6146.6164,3160,7161.0154.0

. . .

. . .

84

Table ll. Mean bone.speclflc skeletal ages forselected hand.wrlst bonesowrors:

Standerd of reference,sex, and chronological


Mele stenderd

Boys:12years .. .. ... .... .. .... .. .... .. ... ... ... ... ... ... .... .. .... ... .... .. .... .. ... ... ... .... . .... .... .. ...13 years ... .... ... ... .. .... .. .... ... .. ... .... ... ... ... ... .. .. .. .... ... .... .. ... ... ... ... ... ... .... .. .. .14 yeers ... ... ... .... .. ... ... ... .... .. .... ... .. .... ... .. .... ... .... .. .... .. ... .... .. .... .. ... .... .. .. . .15yeers ... .... .. .. .... ... ... .. .... ...c..c...c.o.. ... .... .. .... ... .... .. .....4... ... ...i .. .... . ..... .. .16 years . .. ... .... .. ... .... ... .. ... .... ... .. ... .... .. .... .. .... ... ... ... .. .... ... .... ... .. ... .. .. .. ....17 yeers ... .. .... ... .... ... .. ... ... .. .... ... ... ... ... ... ... .... ... .... .. .. .. ... ... .. ... ... ... ... .. .... .

Girls:12 yaars .. .... .. .... .... ... ... .. ... ... ... ... ... .. .... .... .. .... .... . .... ... .... .. ... .. .... .. ... .... .. ..13 yeers ... .... ... .. .... .. ... .... .. ...c.. .. .... ... ... .. ..... .. ... ... ..c. .. .... .. ... .. ..... .. .. .... ... ..14 vOers... ... .... .. .... .. .... .. ... ... .... .. .... ... .. .... .. .... .... .. ... .. .... .. ... ... ... .. ... .... .. ...16yeers .. .... .. .... .... ... .. ... ...) .. .... .. ... .. ... .... ... .... ... ... ... .. .... .. ... .. .... ... .. .. .... ...16 years .... .. .. .... .... ... .. ... .... .. ... .. ... .... ... .. .... ... ... ... . . ... ... .. .... ... ... ... .. .. .... ...17years . ... .... .... ... ... ... .. ... ... ... ... ... .... .. .. ..... ... .. .... .... .. ... .. ..... .. .. ... ... .... .. .. .

Actual When:BOYS 12-17 yeers .. .. .... ... .. .... .. .... .. ... ... ... ... ... .... .. ..... .. .. ... ... .... ... ... .. .... .. ..Girls 12-17 yeers . ... .. .. .. .... .. .... .. .... ... .. ... ... ... .... .. .... .. .... .. .... ... ... ... ... ... ... .

Expacted velues:60YS 12-17 vears ... .... ... ... .. .... ... ... .. ..... .. .. .... ... .. .... .... .. ... ..... .. ... ... .. .... ... .Girls 12-17 years ... ... ... ... ... ... .... .... ... . .... ... ... ... ... .... .. ... .... ... .... .. .. .... .. .... .

Female equivalent

Girls:12 years .. .. ... .... .. .... .... .. .. .... .... ... ... .. .... .. ... .... ... ... ... ... .... . .... ... ... ... ... ... ... ..13 years . ... ... ... .. .. .... .. .. .... ... .. .. .. .... ... .. ..d... .. .. .. .... . ..... .. ... ... ... ... ... .. .. ... .. ...14 years ,..,,.,,..,.. !....... . .... ... ... ... ... ... ... ... .. .... .. .... .. .... .... .. ... .. ... .... ... ... .... ..15 yeers...l . ...i ... .... .. .. ... .. ... .... ... ... ... .... ... .. ... ... ... ... ... ... ... ... .... ... . .... .... .. .. .16 yeers .. ... ... .... ... .. .. ... ... .... .... .. .... ... ... ... ... ... .. .... .. .... .. ... .... .. .... .. ... ... .... ..17yeer: . .... .. ..... .. .... ... .... .... .. .... .... ... .. .... .. ... ..... . ... .... ... .. ..... .. ... .. .... ... . ... .

Male stsmderd

BOYS 12.17 years .. ... .... ... ... ... ... .... ... ... .... ... ... .... .. ... .. .... .. .... .... .. .. ... ... .... ... .. .Girls 12-17 years .. ... ..... .. ... .... ... ... .... .... ... .. .... .. ... .. .. .. .... .... .. ... .. .... .. .... .. .... .. .

~ouths by annual family income, chronologiml ageatlest tifih*y, andsex, with sel~ted standardInited States, 1966-1970-Con.

Distal III

139.0153.6lEa.3173.4177.7165.8

169.717S.6181.8191.01S6.0190.2

158.5176.4

159.s176.S

137.7146.6149.8161.0153.0159.4

138.8157.9168.4175,3178.0185.0

16s.9177.6182.4189.5187.6187.5

159.3176.2

158.2177.4

136.9145.6150.4158.5155.8155,5

141.2155.5168.6176.4181.3190.7

173.4179,0186.2190.8191.0186.0

160.2179.0

159.6177.0

141.4147.0153.4160.6161.0153.0

Distal IV I Distal V

Less Less ~5mo. $lo,ooa

&:&’. $8’,s99 0’more


139.1153.615s.3173.2177.9161.8

169,2177.0179.9186.0186.0166.0

158.5174.6

159.8175.1

137.2145.0147.9153.0153.0153.0

139.0158.8166.6175.3176.3184.4

169.2175.3179,8185.S186,0186.0

159.0174.6

159.0175.5

137.2143.3147.6162,9153.0153.0

141.6156.0158.9176,11s1.1185.8

173.2177.0183,2185.7166.0185.6

159.8176,8

159.1175.0

141.2145.0151.2152,6163.0152.8

139,2153,315s,3173;0177.8181.6

170.0177.3179.8186.0186.0186.0

15s.3174.9

169.8175.2

136.0144.3147.6154.0154.0154.0

138.916s.016s.5175.3177.2184.5

lm.o175.3180.0185.7186.0186.0

159,3174.5

159.1175.5

137.0142.614s.0153.7154.0154.0


. . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . .,. . . . ..! ,.. . . . . . .

141.415s.118s.7176.3161.0185.2

173.2177.4183.21s5.5186.01S5.6

159,8177.0

159.2175.1

140.4144.4151.2153.5154.0153.6

. . .

.!.

85

Table 12, Selected percentiles in the distribution of the individual youth's range in bone-specific skeletal ages fortheradio-opaque (notadult) bones in the handwrist for white and Negro youths by chronological age in years at last birthday and sax: Unitad Statas,1966-1970

Chronological age in years and sex

Boys

12 years .. .. ... .. ... .. ... .. ... .. .... .. .. ... .. ... .. ... .. ... .. .... .. ... ... .. ... ... .. ... .. .. ... ... .. .... . .... ... . ... ... ... .. .... ...13 years .. . . .. . ... ... ... .. . .. .. .... .. .. ... .. .. .. ... ... .. ... .. .... ... . .... .. ... .. .... .. ... .. ... . .... . .... .. .... . .. ... ... .. ..... .14 years ... .. .. ... ... .. ... .. .... .. ... .. .. ... .. ... ... .. .. ... ... .... .. ... .. ... .. ... .... . ... .. .. .. . .. .... .. ... .. .. .. .... .. ... .. ....15 years .. .. ... .. ... ... .. ... ... ... .. .. .... .. ... . ... ... .. ... .. ... .. .. .. .. .. .... .. .. .. .. ... . .. ... ... .. ... ... .. .... . ... .... .. .. .. ..16 years .... ... .. ... . ... ... ... .. .. ... .... . ... ... . .... .. ... .. ... .... .. ... .. ... .. .. .... .. .. ... ... .. ... .. ... ... .. ... ... .. ... ... .. ..17 years ... .. ... ... ... .. .. .. .... .. .... . ... ... .. .. ... ... ... .. .. ... .... ... . ... ... .. ... .. .. .... .. .. .. .. .. ... .. .. ... ... .. ... ... ... ..

Girls—

12 years .. .. .... ... .. .. .. . ... ... .. .. ... ... .. ... .. .. ... ... .. .. .. .. ... .. .. ... ... .. .. .... .. ... . ... ... ... .. ... .. ... . ... ... ... .. ... ..

13 years .. .. ... ... .. ... ... .. .... .. .. .. ... .. ... ... .. ... .. ... .. .. .. . .. .. .. ... . ... ... ... ... .. .. ... .. ... .. .... .. ... . .. .. .. .. ... ... ..

14 years .. . .. ... . ... ... .. ... ... .. ... ... . ... .. ... . .... .. ... .. .... .. ... .. .... .. .. ... .. ... .. .. .. ... .... .. . .... ... . .. .... .. ... ... .. .

15 years .. .. ... ... .. ... .. .. .. ... .. .... .. .. .. ... . .... ... .. ... .. ... ... .. ... .. .... . .. ... ... ... . ... ... .. ... ... .. .. .. .... . ... .. . ... ..16 years ... .. .. .. .. .. ... ... .. .. .. .. . ... .. .... . ... .. .. .... .. .. ... .... . .. .... .. .. ... .... . ... . ... .. .... ... .. .. ... .. ... .. .. ... .. ... .17 years ... .. ... ... ... . .. .. . ... .. ... .. .. .... . ... .. ... .. .... . .... . .... .. ... .. ... .. ... .. ... ... . .... .. ... .. .. .. ... .. ... .. .... .. .. ..

Percentile points

White I Nearo

P75 I P5o ’25 ’75 Ps o ’25

Bone-specific skeletal age range in months-male sta;dard

20.418.8

16.816.014.911.5

19.0

18.9

18,5

17.010.114.5

15.914.612.311.0

8.74.9

14.412.8

10.8

6.82.11.7

12.310.9

8.96.73.70.9

11.0

8.7

5.0

1.60.50.5

20.518.118.213,4

15.316.2

17.918.7

18.5

12,913.913.8

15.013.313,810.0

9.28.4

11.612.5

10.04,63.22.7

12.110.6

8.96.54.22.1

7.89.14,0

0.80.70.6

Table 13. Selectad percentiles in the distribution of the individual youth 'srange in bone-specific skeletal ages fortheradio-opaque (notadult) bonas in the hand-wrist for youths bv geographic region, chronological a!sein years atlast~rthday.a ndsex: United States,,..1966-1970


Bovs

12 years ..... . ... .. ... ... .. ... . ... . .... .. . .... .. .. ... ... .13 years .. .... .. ... ... .. ..o.. ... ... .. ... .. ... .. ... .. .... .14 yaars ... .. .... .. .. .. .... .. .. .... .. ... .. ... .. ... .. ... ..15 years .. ... ... ... . ... ... ... .. ... ... .. .. .... . ... .. .... ..16 years .. .. ... ... .. ... .. .... .. ... ... .. .. ... .. ... .. ... .. .17 years .... ... ... .. ... .. .. .. ... ... ... .. ... ... .. ... . .. .. .

Girls—

12 years ..... . ... ... .. .. ... ... .. .. . ... ... .. ... . .... .. ... .

13 years .... . ... ... ... .. ... ... .. ... ... .. ... ... .. ... .. ... .14 years ... .. .. .... ... .. .. ... .. ... .. ... ... ... .. ... ... .. ..15 years .. ... . ...l .. .. ... ... ... ... ... .. ... ... .. ... .. .. ...16 yaars ... .... ... .. . .. .. ... .. ... ... .. ... .... .. . ... .. ....17 years ... ... ... .. .. .. .. .. ... .. ... .. .... .. ... . .... .. ....

Percentile points

Northeast Midwest South West

J’75 P5 o ’25 P75 P5 o ’25 P75 P50 ’25 f’75 P50 ’25

20.4

18,816.916.714.713.0

18.4

21.020.418.913.819.4

16.0

14.212.110.6

8.83.9

14.212.810.8

6.54.64.2

Bone-specific skelatal age range in months–male standard

12.1

10.68.86.15.00.7

10.6

8.36.21.40.70.6

20.4

18.616.215.616.013.7

18.9

18.918.118.7

8.716.9

15.7 12.3

14.4 12.012.4 8.611.3 7.5

8.6 4.16.5 2.2

14.7 11.9

12.8 8.810.5 4.1

6.7 2.31.0 0.53.0 0.6

20.3

17.718.214.113.2

9.7

18.718.118.513.7

8.26.9

15.0

14.212.610.1

8.55.2

13.0

12.410.7

4.60.90.9

12.3

10.18.86.52.70.9

8.98.25.0

0.80.50.5

20.3

19,116.716.416.412.9

20.0

20.118.416.010.912.1

16,1

15,512.512.010.3

5.1

13,7

12.9

10.6

9.52.60.9

12.3

12,19.46.43.90.9

10.4

9.85.32,40.60.4

86

Table 14. Selected percentiles in the distribution of theindividual youth's rengein bone-specitic skeletal ages fortheradio-opaque {notadult) bones in the hand-wrist forvouths bv annual familv income, chronological age in years at last birthday, and sex: UnitedStates, 1966-1970


Boys

12 years ......................................................................................13 years ,..,..,,,.,...!.,.. ...................................................................14 years ......................................................................................15 years ......................................................................................16 years ......................................................................................17 years ......................................................................................

Girls

12 years ......................................................................................13 years ......................................................................................14 years .... ..................................................................................15 years ......................................................................................16 years ,,.. ,.. ,., ,.,$...,....................................................................17 years ......................................................................................

-.

Percentile points

Lessthan $5,000 I $5,000-$9,999 I $10,000 or moreI I

P75 P50 ’25 P75 P50 ’25 P75 P50 ’25

20.018.618.315.614.113.1

18.418.318.516.112.98.3

8one-specific skeletal age range in months–male standal

15.314.612.811.38.66.7

13.612.610.4

6.82.30.8

12.211.09.06.83.81.6

10.09.66.01.00.50.4

20.719.916.015.416.812.6

19.320.818.618.610.916.9

16.114.812.311.010.14.5

13.013.712.56.92.55.3

12.410.99.06.54.60.7

10.39.05.32.30.50.6

20.418.017.715.113.711.1

19.118.518.319.98.9

12.6

16.014.012.210.6

7.35.1

15.012.4

9.86.52.31.3

12.310.6

8.76.72.61.0

12.27.94.81.00.50.5

Table 15. Median (chronological) aqe of onset of ossification in selected hand-wrist bones for youths 12-17 vears by race, region, annual--family income, and sex: United States, 1966-1970 -

Race, region and annual family income

Race

White ..............................................................................................................................................Negro ..............................................................................................................................................

Region

Northeast ........................................................................................................................................Midwest ..........................................................................................................................................South ..............................................................................................................................................West .......m......m................................................................................................................................

Annual family income

Less than $5.000 .......................................... ..................................................................................$5,000-$9,999 ................................................................................................................................$10,000 or more .............................................................................................................................

Boys I Girls

Adductor I Flexor I Flexorsesamoid sasamoid sesamoid

Chronological age in years

12.412.7

12.512.512.512.5

12.512.412.5

14.214.5

14.013.314.414.4

14.413.113.0

13.013.1

13.113.013.013.0

13.113.012.9

87

Table 16. Median age in months at epiphyseal fusion for selected hand-wrist bones of white and Negro boys and girls 12-17 years ofchronological age at last birthday: United States, 1966-1970

Hand-wrist bone

Radius .... .. . .... . .. . ... .. ... .. ... ... .. .. ... ... .. ... ... . ... ... .. ... ... ... .. ... .. .... . .... . ... ... .. ... ... ... .. .. ... .. ... .. .... . ... ... ......................Ulna . .. ... .. .... . ... ... .. ... ... .. ... .. ... ... . ... ... .. .... .. .. .... . ... ... .. ... ... . ..... .. . ... ... .. .... .. ... . ... .. ... ... ... . ..................................

Metacarpal I . .. ... .. ... .. ... .. ... ... ... .. .. ... ... . ... ... ... .. ... .. .... .. ... .. . .. . .... ... . ... ... .. .... .. .. .... . ... .. .. . ... ... .... . ... .. ..................

Metacarpal II ... .. ... ... .. ... ... .. ... .. .. ... .. .... .. .. ... ... .. ... ... ... .. ... . ... .... .. .. ... ... .. .. ... .. ... .. ... .. . ... . .. ... .. .. .... .. .. ................Metacarpal Ill ... ... .. .. .. ... ... .. ... ... .. .. .. ... ... .. .... .. .. .. ... .... .. .. .... .. ... ... .. .. .. ... ... .. .. .... . ... .. .. .. .. .... .. ... . .... .. .. ..............Metacarpal IV . .. .. .. ... .. .. .... . .... .. ... .. .. ... .. ... ... ... .. ... .. .... .. .. .. .... ... .. ... .. .. .. . ... ... .. ... .. ... ... ... .. .. ... ... .. ... ... .. .. ...........Metacarpal V .... . .. ... ... .. ... ... .. .. .... .. .. ... ... .. ... ... .. .. ... .... .. ... .. ... .. ... ... .. .. .... . .... .. .. ... .. .. .. .. .. ... .. .... .. ... .. .... ............

Proximal phalanx I .... .. .. .... .... ... .. ... ... ... . .... ... .. .. ... .... . ... .. .... .. ... .. .. .. . ... .. .... .. .. ... ... . ... .... .. .. .... .. .. ... ... .. .. .........Proximal phalanx II .... ... .. .. .... .. ... ... ... .. ... .. ... .. ... ... .. .. .. . ... .. ... ... ... . ... ... .. .... ... .. ... .. .. ... ... .. ... ... . .... ... .. ... ... .......Proximal phalanx 111.... .. ... .. .. ... ... ... .. ... ... . .. .. ... .. ... ... .. .. .... .. .. .... ... .. .. ... .. .... .. ... . ..... .. .. ... .. ... ... .. ... ... .. .. ...........Proximal phalanx lV ... ... .. .... . .... .. .. ... ... .. ... ... ... .. .... . ... ... .. ... ... ... .. .. .. .... .. ... .. .. . .. .... . .. .. ... .. .. .... .. .... . ... ... ..........Proximal phalanx V .... .. .... . ... ... ... .. ... .. .. . ... ... .. ... ... ... .. ... .. .... .. ... .. ... ... .. ... .. ... ... . .... .. .. . ... .. ... ... .. ... ... ... . .... .. .....

Middle phalanx II .... ... .. ... .. ... .. ... .. ... .. ... ... ... .. ... .. .... .. .. .... ... .. ... .. .. .. .. ... ... .. ... .. .. ... ... ... .. ... .. .... . ... ... ... .............Middle phalanx Ill .. ... .. .... .. .. .... .. .. .. ... ... ... .. ... .... . ... ... .... . ... .. .... .. .. .... .. .. ... ... ... .. .. .. .... ... ... . .... . .... .. ... .. .... .. ......Middle phalanx IV .. ... .. .... .. .. .. .... .. .. ... ... .. .... ... .. .. ... ... ... .. ... .. ... .. ... ... .... . .... . .... .. .. ... ... ... . .. .. ... ... .. .. ... .. .... . .......Middle phalanx V .. .... .. ... .. .... .. .. .. .. .... ... .. .... .. .. .. .... ... . .. .. ... .. ... .. ... ... .. .. ... ... ... .. ... ... ... .. .... . ... ... . .. . ... ... ... .... .....

Distal phalanx I ... ... .. ... .. ... .. .. ... ... .. ... .. ... .. .... .. ... ... .. ... ... .. ... .. ... ... ... .. ... ... .. ... .. ... ... .. ... .. ... .... . ... ... .... ..............Distal phalanx II .... .. ... .... .. . ... ... .... .. .. .. ... .. ... .. .. ... .. ... .. ... ... .. ... ... .. ... . .... .. .... .. ... .. ... .. .... .. .. .... .. . .... .. ... .............Distal phalanx 111... .. ... .. .. .. . .... .. ... .. ... ... .. .. ... .. ... ... .... .. .. .. .... . .... .. ... ... .. .. .... ... .. ... .. .. .... .. ... .. ... .. ... ... .. ..............Distal phalanx lV .. ... ... . .... .. .... . ... .. .... .. ... .. ... .. ... .. ... .. .... .. ... ... .. ... .. ... .... .. ... .. ... .. .. ... ... .. .... . .... .. ... ... .. ..............

Distal phalanx V ... ... .. ... .. ... ... .. .. ... . .... ... .. .... .. ... .. .. .. . .... . .... . ... .... .. ... .. .. ..... . ... .. .. .. . .. ..... .. ... ... .. .. ... .. ... ... .... .....

*

Median age in months

●

☛

190

198

199199199

195191193193190

193196196195

188189189187

188

●

194

165

178178179180

168168169169168

167169! 69168

162162162161

161

*●

194

199198198199

198194196196

196

197199198198

188188188187188

●

192

167

176175174175

170171171171171

171171172171

160160161159161

*Estimates of median age not possible or not sufficiently reliable forpublication. Theradius had reached the “adult’’s tagef oronly26percent of boys and53 percent ofgirls andtheulna in only 51 percent of boys by 17.9 years.

88

APPENDIXES

CONTENTS

I. Statistical Notes ................................................................................................................................. TOThe Suxvey Design ........................................................................................................................Reliability ..................................................................................................................................... 91SampKng and Measurement Emor ................................................................................................. 92Expected Values ........................................................................................................................... 93Small Numbers ............................................................................................................................. 93

II. Demographic and Socioeconomic Terms ............................................................................................ 95

111. Reliability of Assessments .................................................................................................................. 97Area Skeletal Ages ........................................................................................................................ 98Bone-Specific Skeletal Ages .............................. ............................................................................ 98Factors Influencing Replicabifity ........... ....................................................................................... 98

LIST OF APPENDIX TABLES

I. The number of youths whose radiographs were assessed; the number not assessed refers to youthwho were examined but whose radiographs were missing or of poor quahty: Health ExaminationSurvey, 1966.1970 .......................................................................................................................... 92

II. Number of boys and girls for whom skelctaf age assessments were made on each of the 31 hand-wnst bones: Health Examination Survey, 1966.1970 ...................................................................... 93

111. Mean difference in cross- and self-replicate assessments of bone-specific skeletaf ages from hand-wrist radiographs of examinees 12-17 years old at last birthday, by reader: Health ExaminationSurvey, 1966.1970 .......................................................................................................................... 97

89

APPENDIX 1

STATISTICAL NOTES

The Survey Design

The sample design for the first three pro-grams of Cycles I-III of the Health ExaminationSurvey has been essentially similar in that eachhas been a multistage, stratified probability sam-ple of clusters of households in land-based seg-ments. The successive elements for this sampledesign are primary sampling units, census enu-meration district, segment (a cluster of house-holds), eligible persons, and finally, the sampleperson.

The 40 sample areas and the seagnents util-ized in the design of Cycle III were the same asthose in Cycle II. Previous reports describe indetail the sample design used for Cycle II and, inaddition, discuss the problems and considera-tions given to other types of sampling frames,cluster versus random sampling, and whether ornot to control the selection of siblings.7 Y8

Requirements and limitations placed on thedesign for Cycle III, similar to those for childrenin Cycle II, were that:

1.

2.

The target population be defined as thecivilian noninstitutionalized populationof the United States, including A1askaand Hawaii, between the ages of 12 and17 years for Cycle III, with the specialexclusion of children residing on reserva-tion lands of the American Indians. Thelatter exclusion was due to operationalproblems encountered on these lands inCycle I.

The time period of data collection belimited to “about 3 years for each cycleand the length of the individual examina-

NOTE: A list of references follows the text.

90

3.

4.

5.

tion within the specially constructedmobile examination center be between2 and 3 hours.

Ancillary data be collected on speciallydesi~ed household, medical history andschool questionnaires, and from birthcertificate copies.

Examination objectives be primarily re-lated to factors of physical and intel-lectual growth and development.

The sample be sufficiently large to yieldreliable ~indings within b;oad ~eographicre~ons and population density groups aswell as age, sex, and limited socioeco-nomic groups for the total sample.

The sample was drawn jointly with the U.S.Bureau of the Census starting with the 1960decennial census list of addresses and the nearly1,900 primary sampling units (PSU’S) into whichthe entire United States was divided. Each PSUis either a standard metropolitan statistical area(SMSA), a county, or a group of two or threecontiguous counties. These PSU’S were groupedinto 40 strata, each stratum having an averagesize of about 4.5 million persons, in such a man-ner as to maximize the degree of homogeneitywithin strata with regard to the population sizeof the PSU’S, degree of urbanization, geographicproximity, and degree of industrialization. The40 strata were then classified into 4 broad geo-graphic regions of 10 strata each and then withineach region, cross-classified by four populationdensity classes and classes of rate of populationchange from 1950 to 1960. Using a modifiedGoodman-Kish controlled-selection technique,one PSU was drawn from each of the 40 strata.

Further stages of sampling within PSU’Srequired first the selection of census enumera-tion districts (ED’s). The ED’s me small well-defined areas of about 250 housing units intowhich the entire Nation was divided for the1960 population census. Each ED was assigned a“measure of size” equal to the rounded wholenumber resulting from a “division by nine” ofthe number of children, age 5-9, in the ED at thetime of the 1960 census. A sample of 20 ED’s inthe sample PSU was selected by systematic sam-pling with each ED having a probability of selec-tion proportional to the population of children5-9 years at the time of the 1960 census date. Afurther random selection by size of segments(smaller clusters of housing units) within eachED was then made.

Because of the 3-year time interval betweenCycle II and Cycle III, the Cycle III frame hadto be supplemented for new construction and tocompensate for segments where housing was par-tiaIly or totally demolished to make room forhighway construction or urban redevelopment.

Advanced planning for the examinations atthe various locations or stands provided forabout 17 days of examinations which limitedthe number of examinees per location to ap-proximately 200. When the number of eligibleyouths in the sample drawn for a particular loca-tion exceeded this number, sub sampling wasdone by deleting from the master list of eligibleyouths (ordered by segment, household orderwithin segment, and age within household) everynth name on the list starting with the yth name,y being a number between 1 and n selected ran-domly and n being the extent of oversampling inthe original draw.

In Cycle III, as in Cycle II, twins who weredeleted in the sample selection were also sched-uled for examination, time permitting, as wereyouths deleted from the Cycle III sample whohad been examined in Cycle II. The sample wasselected in Cycle III, as it had been for the chil-dren in Cycle II, so as to contain the correctproportion of youths from families having onlyone eligible youth, two eligible youths, and soon to be representative of the total target popu-lation. However, since households were one ofthe elements in the sample frame, the number ofrelated youths in the resultant sample is greaterthan would come from a design which sampled

youths 12-17 years without regard to household.The resultant estimated mean measurements orrates should be unbiased but their sampling vari-ability will be somewhat greater than those frommore costly, time-consuming systematic sampledesign in which every kth youth would beselected.

The total probability sample for Cycle IIIincluded 7,514 youths representative of theapproximately 22.7 million noninstitutionalizedU.S. youths of 12-17 years. The sample con-tained youths from 25 different States andapproximately 1,000 in each single year of age.

The response rate in Cycle III was 90 per-cent, with 6,768 youths examined out of thetotal sample. These examinees were closelyrepresentative of those in the samples as well asthe population from which the samples weredrawn with respect to age, sex, race, region, pop-ulation density, and population growth in areaof residence. Hence it appears unlikely that non-response could bias the findings appreciably.

Measures used to control the quality ofthe data from these surveys have beencited ;T~s~194~195 these additional measuresspecifically related to skeletal age are outlinedearlier in this report.

Reliability

Although measurement processes in the sur-veys were carefully standardized and closelycontrolled, the correspondence between the realworld and survey results cannot be expected tobe exact. Survey data are imperfect for threemajor reasons: (1) results are subject to samplingerror, (2) the actual conduct of a survey neveragrees perfectly with the design, and (3) themeasurement processes themselves are inexacteven though standardized and controlled.

The first report on Cycle 1118 describes indetail the faithfulness with which the samplingdesign was carried out.

Data recorded for each sample youth areinflated in the estimation process to characterizethe larger universe of which the sample youth isrepresentative. The weights used in this inflationprocess are a product of the reciprocal of theprobability of selecting the youth, an adjust-ment for nonresponse cases, and a poststratifiedratio adjustment which increases precision bybringing survey results into closer alignment

91

with known U.S. population figures by colorand sex within single years of age 12 through 17for the youths’ survey.

Ln the third cycle of the Health ExaminationSurvey (as for the children in Cycle II) the sam-ples were the result of three principal stages ofselection—the single PSU from each stratum, the20 segments from each sample PSU, and thesample youth from the eligible persons.1 96 Y197The probability of selecting an individual youthis the product of the probability of selection ateach stage.

Since the strata are roughly equal in popula-tion size and a nearly equal number of sampleyouths were examined in each of the samplePSU’S, the sample design is essentially self-weighting with respect to the target population;that is, each youth 12 through 17 years hadabout the same probability of being drawn intothe respective samples.

The adjustment upward for nonresponse isintended to minimize the impact of nonresponseon final estimates by imputing to nonresp ond-ents the characteristics of “similar” respondents.Here “similar” respondents were judged to beexamined youths in a sample PSU having thesame age (in years) and sex as youths not ex-amined in that sample PSU.

The poststratified ratio adjustment used inthe third cycle achieved most of the gains inprecision that would have been attained if thesample had been drawn from a population strati-fied by age, color, and sex and makes the finalsample estimates of population agree exactlywith independent controls prepared by the Bur-eau of the Census for the U.S. noninstitu-tionalized population as of March 9, 1968(approximate midsurvey point for Cycle III) bycolor and sex for each single year of age 12-17.The weights of every responding sample youthin each of the 24 age, color, and sex classes isadjusted upward or downward so that theweighted total within the class equals the inde-pendent population control for each survey.

In addition to youths not examined at all,there were 32 for whom there was no radiographor else the radiograph could not be assessed. Theage and sex distribution for these 32 youths aswell as for the 6,736 for whom assessments weremade is shown in table I. The skeletal ages forthese youths without usable radiographs were

Table 1, The number of youths whose radiographs were assessed;the number not assessed refers to youths who were ex-amined but whose radiographs were missing or of poorquality: Health Examination Survey, 1966-1970

Age

Total .........................

12 years ...............................13 years ...............................14 years ...............................15 years ...............................16 years ...............................17 years ...............................

3,534

840625617610555487

Number of youths

3,202

543582584503528462

11

311312

21

4

2

87

not estimated. It is assumed that the distributionof their skeletal ages is similar to that for theremaining 6,736. In other words, they weretreated as nonresponders.

Sampling and Measurement Error

In the present report, reference has beenmade to efforts to minimize bias and variabilityof measurement techniques.

The probability design of the survey makespossible the calculation of sampling errors. Thesampling error is used here to determine howimprecise the survey test results may be becausethey come from a sample rather than from themeasurements of all elements in the universe.

The estimation of sampling errors for astudy of the type of the Health ExaminationSurvey is difficult for at least three reasons: (1)measurement error and “pure” sampling errorare confounded in the data—it is not easy to finda procedure which will either completely includeboth or treat one or the other separately, (2) thesurvey design and estimation procedure are com-plex and accordingly require computationallyinvolved techniques for the calculation of vari-ances, and (3) from the survey are coming thou-sands of statistics, many for subclasses of thepopulation for which there are a small numberof cases. Estimates of sampling error are ob-tained from the sample data and are themselvessubject to sampling error which may be largewhen the number of cases in a cell is small or

92

evsm occasionally when the number of cases issubstantial.

Estimates of approximate sarnplingvariabil-ity for selected statistics used in this report areincluded in the detailed tables. These estimateshave been prepared by a replication techniquethat yields overall variability through observa-tion of variability among random subsarnples ofthe total sample. The method reflects both“pure” sampling variance and a part of the meas-urement variance.

In accordance with usual practice, the inter-val estimate for any statistic may be consideredthe range within 1 standard error of the tabu-lated statistic, with 68-percent confidence; orthe range within 2 standard errors of the tabu-lated statistic, with 95-percent confidence. Thelatter is used as the level of significance in thisreport.

An approximation of the standard error of adifference d = x - y of two statistics x and y is,giwm by the formula

Sd = (s%2+ s; )%

where SX and SY are the sampIing errors, respec-tively, of x and y. Of course, where the twogroups of measures are positively or negativelycorrelated, this will give an overestimate orunderestimate, respectively, of the actualstandard error.

Expected Values

In the detailed tables both the actual andcxpcctcd mean skeletal ages are shown for chil-dren in the various demographic groups. Theexpected mean values are obtained by assumingthat the national age-specific mean values applywithin the appropriate age subgroup for whichthe value is derived.

For example, if in an area (e.g., the North-east ), estimates from the Health ExaminationSurvey show ni boys in the ith age group(i=l,2,..., 6; ~ ni = n) and the estimates ofmean skeletal age for all U.S. boys in the ith agegroup to be <Yi>then the expected mean skeletalage for boys in that area is:

The specific area may have higher values foryounger boys and lower values for older boysthan in the other areas. In that case, the ex-pected average may obliterate one or both ofthese differentials. These types of limitationsneed to be kept in mind in interpreting thesedata. The standard error of the difference be-tween an actual and an expected mean valuemay be approximated by the standard error ofthe actual value.

Table II. Number of boys and girls for whom skeletal age assess-ments were made on each of the 31 hand-wrist bones:Health Examination Survey, 1966-1970

Bone

Radius . ... .... . ... .. .. . ... ... . .... .. ..Ulna .. ... ... .. .... .. .. .. ... . .. ... .. .. ..

Cavitate . .. .. .. .. .. ... ... .. .. ... ... .. .Hamate . ... .. . ... .. .... .. .. ... . .... ...Triquetral . ... ... .. ... .. ... .. .. ... ...Lunate . .... .. .. .... .. ... .. ... .. .. .. ...Scaphoid . .... ... ... .. . .. ..... .. .. .. .Trapezium .. .. .. .. .. ... ... .. .. .. . ...

Trapezoid .... ... ... ... .. .. .. .. .. .. ..

Metacarpal 1 ..... . .. .. .... .. .. .. ...Metacarpal II .... .. .. .. ... .. ... . ...Metacarpal [[l .. ... .. .. ... . .... .. ..Matacarpai IV . .. .. .. .. ... .. ... .. ..Metacarpal V ... ... .. .. ... .. .. ... ..

Proximal phalanx 1.. .. .. .... .. .

Proximal phalanx I 1... .. .... . ..

Proximal phalanx Ill .... ... ...

Proximal phalanx IV ... .. . ... .Proximal phalanx V .... ... .. .. .

Middle phalanx II .. .... . .. .. . ...

Middle phalanx Ill . .... .. ... . ...Middle phalanx IV .. ... .. ... ... .Middle phalanx V ... .... . .... .. .

Distal phalanx 1... ... .. .. ... .. ...Distal phalanx I l .. .. ... ... ... . .. .Distal phalanx Ill ... .... . ... ... .Distal phalanx IV .... ... . ... ....Distal phalanx V ..... . ... ... .. ...

Pisiform ..... .. ... ... .. .. .. .... .. ... ..

Adductor sesamoid .... .. .. .. ...Flexor sesamoid ... ... ... . ... ... .

Number

3,4453,286

2,0111,9862,0072,0002,0172,007

1,995

2,4482,7592,738

2,7292,799

2,638

2,588

2,591

2,5842,576

2,618

2,6512,6482,625

2,2962,3392,3352,2982,307

1,7731,5111,095

2,9772,407

759741752756776780

768

1,1281,5901,560

1,5771,701

1,3981,319

1,346

1,3501,327

1,316

1,3721,3771,292

968982974893893

744908746

1111

112312

2

111

1

2

21

1

11

1111

12212

166574

1,052

64

111111

1

111

1

1

31

111

1112

31211

1025

264

93

Small Numbers

In some tables, magnitudes are shown forcells for which the sample size is so small thatthe sampling error may be several times as greatas the statistic itself. Obviously, in such in-stances the statistic has no meaning in itselfexcept to indicate that the true quantity issmall. Such numbers, if shown, have been in-cluded in the belief that they may help to con-

vey an impression of the overall story of thetable.

Among the 6,736 children with usable radio-graphs, there were a few of inadequate qualityto permit assessment of all bones. In general,these would have been bones that became radio-opaque recently or bones near the margin of theradiographic field. The number of youths forwhom bone-specific skeletal ages were assignedand the numbers in which particular bones wereadult are shown in table II.

000

94

APPENDIX II

DEMOGRAPHIC AND SOCIOECONOMIC TERMS

Age. –The age recorded for each youth wasthe age at last birthday on the date of examina-tion. The age criterion for inclusion in the sam-ple used in this survey was defined in terms ofage at time of interview. Since the examinationusually took place 2-4 weeks after the interview,some of those who were 17 years old at the timeof interview became 18 years old by the time ofexamination. There were 23 such cases. In theadjustment and weighting procedures used toproduce national estimates these 23 were in-cluded in the 17-year-old group.

Race. –Race was recorded as “white,”“Negro,” or “other. “ “Other” included Ameri-can Indians, Chinese, Japanese, and all racesother than white or Negro. Mexican personswere included with “white” unless definitelyknown to be American Indian or of other non-white race. Negroes and persons of mixed Negroand other parentage were recorded as “Negro. ”

Geographic region. –For purposes of stratifi-cation, the United States was divided into fourbroad geographic regions of approximately equalpopulation. These regions, which correspondclosely to those used by the Bureau of theCensus, were as follows:

Rc@”on

Northeast . . . . .

Midwest. . . . . . .

States included

Maine, Vermont, New Hamp-shire, Massachusettss, Connec-ticut, Rhode Island, NewYork, New Jersey, and Penn-sylvania

Ohio, Illinois, Indiana, Michi-gan, Wisconsin, Minnesota,Iowa, and Missouri

South . . . . . . . . Delaware, Maryland, Districtof Columbia, West Virginia,Virginia, Kentucky, Tennes-see, North Carolina, SouthCarolina, Georgia, Florida,Alabama, Mississippi, Louisi-ana, and Arkansas

West: . . . . . . . . Washington, Oregon, Califor-nia, Nevada, New Mexico,Arizona, Texas, Oklahoma,Kansas, Nebraska, North Da-kota, South Dakota, Idaho,Utah, Colorado, Montana,Wyoming, Alaska, and Hawaii

Urban-rural. –The definition of urban-ruralareas was the same as that used in the 1960Census. According to this definition, the urbanpopulation was comprised of all persons living in(a) places of 2,500 inhabitants or more incor-porated as cities, boroughs, villages, and towns(except towns in New England, New York, andWisconsin); (b) the densely settled urban fringe,whether incorporated or unincorporated ofurbanized areas; (c) towns in New England andtownships in New Jersey and Pennsylvania thatcontained no incorporated municipalities as sub-divisions and had either 2,500 inhabitants ormore, or a population of 2,500 to 25,000 and adensity of 1,500 persons or more per squaremile; (d) counties in States other than the NewEngland States, New Jersey, and Pennsylvaniathat had no incorporated municipalities withintheir boundaries and had a density of 1,500 per-sons or more per square mile; and (e) unincor-porated places of 2,500 inhabitants or more notincluded in any urban fringe. The remainingpopulation was classified as rural.

95

Urban areas are further classified by popula-tion size for places within urbanized areas andother urban places outside urbanized areas.

Grade in school. –The grade that the youthattended at the time of interview was used hereand later verified against school records. Thegrade of those youths on summer vacation wasconsidered to be the grade that they would enterwhen school resumed.

Education of parent or guardian. –This wasrecorded as the highest grade completed inschool. The only grades counted were thoseattended in a regular school where persons weregiven formal education in graded public or pri-vate schools, whether day or night school, andwhether attendance was full or part time. A“regular” school is one that advances a persontoward an elementary or high school diploma, ora college, university, or professional schooldegree. Education in vocational, trade, or busi-ness schools outside the regular school systemwas not counted in determining the highestgrade of school completed.

Family income. –The income recorded wasthe total income of the past 12 months receivedby the head of the household and all other

o

household members relatedblood, marriage, or adoption.

to the head byThis income was

the gross cas~ income (excluding pay in kind)except in the case of a family with their ownfarm or business, in which case net income wasrecorded.

Parent. –A parent was the natural parent or,in the case of adoption, the legal parent of theyouth.

Guardian. –A guardian was responsible forthe care and supervision of the youth. He (orshe) did not have to be the legal guardian to bc

considered the guardian for this survey. A guard-ianship could only exist when the parent(s) ofthe youth did not reside within the samplehousehold.

Head of household. –OnIy one person ineach household was designated as the “head.”He (or she) was the person who was regarded asthe “head” by the members of the household. Inmost cases the head was the chief breadwinnerof the family, although this was not always true.In some cases the head was the parent of the

chief earner, orhousehold.

00

the only adult member of the

96

APPENDIX Ill

RELIABILITY OF ASSESSMENTS

T(J provide the basis for determining theh.wl of reliability of the bone-specified skeletal:i,~c’ assessments made by the nine medical stu-dents at Case Western Reserve University fromhand-wrist radiographs of the 12-1 7-year-oldyouths examined in the Health ExaminationSurvey of 1966-1970, a randomly selected ‘sam-ple of 1 in 23 radiographs was reassessed by thesame reuder and approximately 1 in 20 inde-pcmdcntly randomly selected radiographs werereassessed by another reader, as described pre-vi( msly. All nine readers, before starting thesefind assessments, had been trained by Dr. Pylein the Greulich-Pyle method using the “HESStandard” to the point that their assessmentswere in close agreement with hers. In all, 351SC*1f-n.’plicate assessments and 301 cross-replicateassessments were made. Each reader made:Ipproximately the same number of self-replicate:tnd cross-replicate assessments.

All nine readers maintained a high level ofconsistency in their own assessments throughoutall 40 examination stands of the survey. Themean difference in self-replicate assessments forall nine readers was 0.1 month for all 31 bonesas well as for the 28 bones from which thosethat were late to ossify (the pisiform, adductorsesamoid and flexor sesamoid) were excluded.Considering data for all 31 bones, the mean dif-ference per reader between original and self-replicate assessments ranged from 0.2 to 1.7months combining data from both sexes. Forthe 28 bones that ossify relatively early, themean differences range from 0.2 to 1.6 monthsamong the nine readers (table III).

A consistently high level of agreement inbone-specific skeletal age assessments was main-tained among the nine readers but the level was,as expected, somewhat lower than that for theindividual readers with themselves. The mean

Table I I 1. Mean difference in cross- and self-replicate assessments of bone-specif ic skeletal ages f rom hand-wrists radiographs of examinees

12-17 years old at last birthday, by reader: Health Examination Survey, 1966-1970

Reader

All readers . .... .. .. ... ... ... ... .. .... .. .. .. .. ... ... .. .. ... ... .. .. .. .. .. ... .. .. ... ... .. ... .. .. ... ... .. .. .. ..

Reader 21 ... .. ... . .... .... .. ... .. ... ... ... ... ... .. ... ... ... ... .. ... ... .. ... ... .. .. ... ... ... . ... .. ... .. ... ... .. .. ... .. ... .. .Reader 22 ... .. ... ... .. .... .. .. .... .. .... ... .. ... ... ... .. .... .. ... .. ... ... .. ... ... .. .. ... ... .. ... .. .. .. ... ... .. .. .. ... ... . ..

Reader 24 .. ... ... ... .. .... .. ... .. .... .. ... .... .. .... .. ... ... .. ... ... .. .. ... ... ... ... .. .. ... ... . ... ... .. .. .. ... ... .. .. ... ...

Reader 25 ... ... .. ... ..... .. .. ... ... .. .... ... ... .. ... .. ... .. .. .. .. ... .. ... .. .. .... .. ... .. .. ... ... . .... .. .. .. .. .... .. .. .. ... .Fk?ader 26 . .. .... .. .... ... ... .. ... ... ... ... ... .. .. ... .. .... .. .. ... .... . ... ... .. ... ... .. .. ... .. ... .. .. ... .. ... .. .. ... .. ... .. .Reader 27 .. .. .... .. .... .... .. ... . ... ... ... ... .. ... .. ... ... ... .. .. .. .... .. .. .. .. .. .. .. .. .... .. ... .. .. ... .. ... .. ... .. .. ... .. .Reader 28 . .... ... .... ... .. ... ... ... .. .. .... .. .. ... ... ... ... .. .. .. .... .. .. .. .... . ... .. ... .. ... .. ... ... .. .. .. ... ... .. ... ... ..Reader 29 .. ... .... .. .. .... ... ... .. ... .. ... .... .. .. ... . .. .. ... ... . ... .. ... .. ... .. .. ... ... .. ... .. ... ... . ... ... .. .. .. ... ... .. .

Reader 30 .. .. .... ... .. .... . .. .. .. .. .. .. ... ... .... . ... .... . ... .. ... ... .. .. .... .. .. ... . .. .. .. .. ... ... .. .. .. ... ... .. ... . .... ..

Self- Cross-Numberof films

replicates replicatesreplicated

31 28 31 28

oones bones bones bonesSelf Cross

Mean difference

-0.1

1.6-1.2

-1.7

0.5-0.2

-0.30.30.2

-1.0

-0.1

1.6-1.4

-1.60.4

-0.2-0.30.20.3

-1.0

===+== 1=351

L0.7 0.8

-2.3 -2.1

-1.7 -1.6

2.6 2.4

-0.8 -0.5-1.5 -1.71.0 1.3

-1.0 -0.8

-1.3 -1.0

3636

21

66

4444443030

301

3230

20

56

32433327

28

97

cross-replicatebones was 0.2

difference for all 31 hand-wristmonth. It ranged between 0.7 and

2.6 months for the readers: When only the 28centers that are relatively early to ossify wereconsidered, the overall mean difference wasslightly less–O. 1 month–and ranged from 0.8 to2.4 months among the individual readers.

The aspects considered include consistencywit hi n observers (intraobserver differences),comparability between observers (interobserverdifferences), and differences resulting from vari-ations in the way the Greulich-Pyle Atlas hasbeen used. This review is restricted to reportsbased on samples of at least 10 radiographs andto the chronological age range 12-17 years.

Although it is impossible at present to deter-mine the true maturity level of the bones visual-ized in a radiograph, it is necessary to define thereliability of assessments both within and be-tween observers. As stated by Greulich andPyle: 10 “Though the ability to duplicate assess-ments with a good degree of consistency mustbe possessed by a competent assessor, it alone isnot enough. It is even more important that theassessments be made correctly, that is, that theybe made according to the method recommendedby the particular radiographic atlas on whichthey purport to be based. ” Unfortunately, thesuggestion by Moorel 9 G that sets of duplicateradiographs that have been assessed by recog-nized experts be available to those who wish tomeasure their level of comparability has notbeen implemented.

Area Skeletal Age

It is not easy to compare reported findingsbecause workers have analyzed their data in dif-ferent ways. For intraobserver differences,95-percent confidence limits of 7.2 monthsl97and mean differences ranging from 1.2 to 6.6months have been reported,z 8~19 S‘z OI in addi-tion to variable errors to 1,4 to 4.2

months.z0z~z03 The median intraobserver dif-ferences range from zero to 4 months.z OA~zOs Areport of zero median differences seems surpris-ing but it is possible because Moed and his co-workers made overall assessments to the nearestatlas standard.

Todd’sl 8 claim that interobserver differ-ences less than 6 months could be achieved read-ily appears justified. Reported mean interob-server differences range from 1.3 to 4.2months.zOO~zOG~zO T In addition, a root meansquare of 6.2 months and confidence limits of7.4 months have been reported.1 g T~z01 Re-ported incidence of particular interobserver dif-ferences indicate that the medians were less than3 months for the study by Hansman andMareshG G and less than 6 months for the studyby Moed et al.zOA

Bone-Specific Skeletal Ages

Moorel96 reported interobserver differencesthat were Iess than 12 months in 94 percent ofbones.

Factors Influencing Replicability

There is no indication that the level of repli-cability is related to the differences betweenchronological and skeletal ages. 199 ~z02 How-ever, the range of maturity between the bones ofa hand-wrist influences the replicabilit y of over-all but not bone-specific assessments.19 9‘2 00The quality of the radiographs (exposure, posi-tioning) has no effect on replicability within therange that is common in research studiesz00 butunusually poor radiographic quality does reducereplicability.z 0z The method by which theGreulich-Pyle Atlas is used has an effect.Maresh22 reported a technical error of 3.0months between overall assessments and thoseobtained as the means of bone-specific skeletalages.

NOTE: A list of references follows the text.

98

Series 1.

Series 2.

Series 3.

Series 4.

VITAL AND HEALTH STATISTICS Series

Programs and Collection Procedures. –Reports which describe the general programs of the NationalCenter for Health Statistics and its offices and divisions and data collection methods used and includedefinitions and other material necessa~ for understanding the data.

Data Evaluation and Methods Research. –Studies of new statistical methodology including experi-mental tests of new survey methods, studies of vital statistics collection methods, new analyticaltechniques, objective evaluations of reliability of coIlected data, and contributions to statistical theory.

Analytical Studies. –Reports presenting analytical or interpretive studies based on vital and healthstatistics, carrying the analysis further than the expository types of reports in the other series.

Documents and Committee Reborts. –Final reports of maior committees concerned with vital and

/

health statistics and documents- such as recommended moc&l vital registration laws and revised birthand death certificates.

Series 20. Data From ~the Health Interview Sumey. –Statistics on illness, accidental injuries, disability, use ofhospital, medical, dental, and other services, and other health-related topics, all based on data collectedin a continuing national household interview survey.

Series 11. Data From the Health Examination Survey and the Health and Nutrition Examination Survey. –Datafrom direct examination, testing, and measurement of national samples of the civilian noninstitu-tionalized population provide the basis for two types of reports: (1) estimates of the medically definedprevalence ,of specific diseases in the United States and the distributions of the population with respectto physical; physiological, and psychological characteristics and (2) analysis of relationships among thevarious measurements witbout reference to an explicit finite universe of persons.

Series 12. Data From the Institutionalized Population Surveys. –Discontinued effective 1975. Future reports fromthese surveys will be in Series 13.

Series 13. Data on Health Resources Utilization. –Statistics on the utilization of health manpower and facilitiesproviding long-term case, ambulatory care, hospital care, and family planning services.

Series 14. Data on Health Resources: Manpower and Facilities. –Statistics on the numbers, geographic distri-bution, and characteristics of health resources including physicians, dentists, nurses, other healthoccupations, hospitals, nursing homes, and outpatient facilities.

Series 20. Data on Mortality. –Various statistics on mortality other than as included in regular annual or monthlyreports. Special analyses by cause of death, age, and other demographic variables; geographic and timeseries analyses; and statistics on characteristics of deaths not available from the vitaI records based onsample surveys of those records.

Series 21. Data on Natality, Marriage, and Divorce. –Various statistics on natality, marriage, and divorce otherthan as included in regular annual or monthly reports. Special analyses by demographic variables;geographic and time series analyses; studies of fertility; and statistics on characteristics of births notavailable from the vital records based on sample surveys of those records.

Sm”es 22. Data From the National Mortality and Natality Surveys.–Discontinued effective 1975. Future reportsfrom these sample surveys based on vital records will be included in Series 20 and 21, respectively.

Sm”es 23. Data From the National Survey of Family Growth. –Statistics on fertility, family formation and dis-solution, family planning, and related maternal and infant health topics derived from a biennial surveyof a nationwide probabtiity sample of ever-married women 15-44 years of age.

For a list of titles of reports published in these series, write to: Scientific and Technical Information BranchNational Center for Health StatisticsPublic Health ServiceHyattsville, Md. 20782

i,-& .-

NCHSu S DEPARTMENT OF HEALTH, EDUCATION, AND WELFAREP“bl, c He.?llb &WC.

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