Post on 04-Jul-2020
Forensic Anthropology:
Studying Bones
Cranium
Cervical Vertebrae
Sternum
Humerus
Ulna
Radius
Carpals
Metacarpals
Phalanges
Sacrum
Tibia
Fibula
Tarsals
Metatarsals
Phalanges
Clavicle
Scapula
Ribs
Lumbar Vertebrae
Ilium
Ishium
Femur
Patella
Directions:
Identify the bones.
Osteology: Study of Bones
• Each bone studied INDIVIDUALLY
Osteology
Osteology
Forensic Anthropology:
-The study of human skeletal remains to determine sex, age,
race, and time of death in an effort to identify an individual.
- It includes newer topics of facial reconstruction and age
progression.
- “anthropo” is Greek for humankind or man, logos means
“the study of”.
A Caveat Before we Start:
• Informative features about the age, sex, race and stature of individuals based on bones is based on biological differences between sexes and races (males are generally taller and more robust) as well as differences due to ancestry (certain skeletal features of the skull).
• However, it is imprecise because so much human variation exists and because racial differences tend to homogenize as populations interbreed.
• Still differences do exist and the more features you survey, the more precise your conclusions would be.
What Can We Learn?
• Determination of Sex – Pelvis
– Skull
• Determination of Race – Skull
• Approximate Age – Growth of long bones
• Approximate Stature – Length of long bones
• Postmortem, perimortem or
antimortem injuries.
1. Determination of Sex • Pelvis is the best bone (differences due to
adaptations to childbirth):
females have wider sub-pubic arch angle.
females have a sciatic notch > 90°
females have a broad pelvic inlet
1. 1.
1.
2. 2.
2.
3. 3.
3.
Determination of Sex
• Pelvis best (another view)
females have wider subpubic angle
females have a broad, shovel-like ilium
females have a flexible pubic symphysis
1. 1.
2. 2. 3.
1.
2.
3.
Information from skeletal remains Sex of decedent
Male Female
Determination of Sex
Cranium second best, Pelvis = Best.
• Crests and ridges are more
pronounced in males (A, B, C, H).
• Chin significantly more square in
males (E).
• Jaw (I, E), mastoid process wide
and robust in males.
• Forehead slopes more in males (F).
Determination of Sex
• Normally, the long bones alone
are not used to estimate gender.
However, if these bones are the
only ones present, there are
characteristics that can be used
for sex determination.
• E.g. maximum length of humerus
in females is 305.9 mm, while it is
339.0 mm in males
Sex Determination - Skull
Trait Female Male
Upper Edge of Eye Orbit Sharp Blunt
Shape of Eye Orbit Round Square
Zygomatic Process
Not expressed beyond
external auditory
meatus
Expressed beyond external
auditory meatus
Nuchal Crest (Occipital
Bone) Smooth Rough and bumpy
External Occipital
Protuberance Generally Absent Generally present
Frontal Bone Round, globular Low, slanting
Mandible shape Rounded, V-shaped Square, U-shaped
Ramus of mandible Slanting Straight
2. Determination of Race • It can be extremely difficult to determine the true race of
a skeleton for several reasons: – First, forensic anthropologists generally use a three-race
model to categorize skeletal traits: Caucasian (European), Asian (Asian/Amerindian), and African (African and West Indian).
– Although there are certainly some common physical characteristics among these groups, not all individuals have skeletal traits that are completely consistent with their geographic origin.
– Second, people of mixed racial ancestry are common. • Often times, a skeleton exhibits characteristics of more than one racial
group and does not fit neatly into the three-race model.
– Also, the vast majority of the skeletal indicators used to determine race are non-metric traits which can be highly subjective.
• Despite these drawbacks, race determination is viewed as a critical part of the overall identification of an individual's remains.
Determination of Race
– A THREE-RACE model is used to categorize skeletal traits:)
• Caucasoid = Europe, North Africa, West Asian
• Mongoloid = East Asia, Arctic, Native Americans( North and South)
• Negroid = Sub-Saharan Africa
White, Asian, African
From: Beyers, S.N. (2005). Introduction to Forensic Anthropology
Two ways of determining race
of a skull • Empirical = measurable
– Cranial Index
– Facial Index
– Nasal Index
• Observational = non-measurable
– Eye Orbit Shape
– Mastoid Process size/projection
– Prognathism
Empirical Measurements taken on a skull
• Nasal Index: Nasal
breadth divided by nasal
height
• Nasal Breadth (mm)=
distance from alare to
alare (al).
• Nasal Height (mm) =
distance from naison
(n) to nasospinale (ns).
Empirical Measurements
• Cranial Index: the
ratio between cranial
breadth and cranial
height
– Breadth (mm) =
euryon (eu) to
euryon (eu).
– Height (mm) =
Glabella (g) to
Opistocranium (op)
Empirical Measurements • Facial Index: Facial
height divided by Facial
width
• Facial Height (mm) =
distance from nasion
(n) to gnathion (gn)
• Facial width (mm) =
distance from zygion
(zy) to zygion.(zy)
(width)
Non-measurable features of
skulls
• Nasal Spine: Bony
projection that sticks
out at the base of the
nose.
• The shape of nasal
spine varies between
races.
Nasal Silling and Guttering
Nasal Silling: the
bottom of the nasal
spine points outward
forming a “spout”.
Nasal Guttering:
lacking a sill at the
bottom of the nasal
aperture.
Non-measurable features of
skulls: Gonial Angle
• Gonial angle: The
angle of the jaw.
• Related to the face
shape
• Referred to as either
rounded or not
rounded.
Non-measurable features of
skulls: Shape of Mandible
• Mandible: The shape
of the jaw
• Referred to as either
rounded or squared.
Round or Squared?
Non-measurable features of skulls: Face Shape
• Prognathism: The
protruding of the
lower jaw.
• Most evident in
Negroid skulls.
• Orthognathism:
No protrusion of
lower jaw.
• Most evident in
caucasoid
skulls
Non-measurable features of skulls: Eye Orbit • Eye Orbit: The bony area surrounding an eyeball. Usually described as
one of four shapes using a combination of the descriptions below:
• Round or Squared
• Slanted or Not Slanted
General Shapes of the Eye Orbits
Determination of Race: Caucasoid/European
Trait
Cranial Index .75-.80
Nasal Index: Less than .48
Facial Index: Greater than .90
Nasal Spine: Prominant
Face Shape: Orthognathic
Eye Orbits Squared and
Slanted
Gonial Angle Slightly flared
Nasal spine:
Prominent
Orbital
openings:
round
Determination of Race: Asian/Mongoloid
Trait
Cranial Index Greater than .80
Nasal Index .48-.53
Facial Index .85-.90
Nasal Spine Small
Face Shape Variable
Shape of
Orbital
Openings
Rounded, not
slanted
Determination of Race: African (Negroid)
Trait
Cranial Index .75 or less
Nasal Index .53 or greater
Facial Index .85 or less
Nasal Spine Very small spine
Face Shape Prognathic
Shape of
Orbital
Openings
Rectangular and
straight
Trait Caucasoid Negroid Mongoloid
Cranial Index .74 -.79 .75 or less .80 or more
Nasal Index Less than .48 .53 or greater .49-.52
Facial Index Greater than
.90
.85 or less .86-.89
Facial Profile/Shape Orthognathic Prognathic Variable
Eye Orbit
Shape/Direction
Squared and
Slanted
Squared and
Straight
Rounded and
Straight
Gonial Angle Shape Slightly Flared
(a little over 90)
Straight (very
close to 90)
Flared (greater
than 90)
Chin Profile Pointed Flat Flat
3. Determination of Age from
Bones • Ages 0-5: teeth are best – forensic odontology
– Baby teeth are lost and adult teeth erupt in predictable patterns
• Ages 6-25: epiphyseal fusion – fusion of bone ends to bone shaft – epiphyseal fusion varies with sex and is typically
complete by age 25
• Ages 25-40: very hard
• Ages 40+: basically wear and tear on bones – periodontal disease, arthritis, breakdown of pelvis,
etc.
• Can also use ossification of bones such as those found in the cranium
Determination of Age
• The long bones are those that grow primarily by elongation at an epiphysis at one end of the growing bone. The long bones include the femurs, tibias, and fibulas of the legs, the humeri, radii, and ulnas of the arms, and the phalanges of the fingers and toes.
• As a child grows the epiphyses become calcified (turn to hard bone)
Epiphyseal Fusion
• The figures below are of the Epiphyses of the femur or thigh bone (the ball end of the joint, joined by a layer of cartilage).
• The lines in the illustrated Image 1 show the lines or layers of cartilage between the bone and the epiphyses. The lines are very clear on the bone when a person, either male or female is not out of puberty.
• In Image 2, you see no visible lines. This person is out of puberty. The epiphyses have fully joined when a person reaches adulthood, closing off the ability to grow taller or in the case of the arms, to grow longer.
Figure 1. Figure 2.
Epiphyseal Fusion:
A General Guide
Age at Death Long Bone Development
Determination of Age from Bone: Signs of
wearing and antemortem injury
Occupational stress wears
bones at joints Surgeries or healed wounds
aid in identification
Age Determination: Use of Teeth
4. Determination of Stature
• Long bone length (femur, tibia, humerus) is proportional to height
• There are tables that forensic anthropologists use (but these also depend to some extent on race)
• Since this is inexact, there are ‘confidence intervals’ assigned to each calculation.
• For example, imagine from a skull and pelvis you determined the individual was an adult Caucasian, the height would be determine by:
• Humerus length = 30.8 cm
• Height = 2.89 (MLH) + 78.10 cm = 2.89 (30.8) + 78.10 cm
= 167 cm (5’6”) ± 4.57 cm
See your lab handout for more tables
BONE RACE MALE EQUATION FEMALE EQUATION
Femur
Caucasoid 2.32 x femur + 65.53 ± 3.94 cm 2.47 x femur + 54.10 ± 3.72 cm
Negroid 2.10 x femur + 72.22 ± 3.91 cm 2.28 x femur + 59.76 ± 3.41 cm
Mongoloid 2.15 x femur + 72.57 ± 3.80 cm (Use Male)
Tibia
Caucasoid 2.42 x tibia + 81.93 ± 4.00 cm 2.90 x tibia + 61.53 ± 3.66 cm
Negroid 2.19 x tibia + 85.36 ± 3.96 cm 2.45 x tibia + 72.56 ± 3.70 cm
Mongoloid 2.39 x tibia + 81.45 ± 3.24 cm (Use Male)
Fibula
Caucasoid 2.60 x fibula + 75.50 ± 3.86 cm 2.93 x fibula + 59.61 ± 3.57 cm
Negroid 2.34 x fibula + 80.07 ± 4.02 cm 2.49 x fibula + 70.90 ± 3.80 cm
Mongoloid 2.40 x fibula + 80.56 ± 3.24 cm (Use Male)
Humerus
Caucasoid 2.89 x humerus + 78.10 ± 4.57 cm 3.36 x humerus + 57.97 ± 4.45 cm
Negroid 2.88 x humerus + 75.48 ± 4.23 cm 3.08 x humerus + 64.67 ± 4.25 cm
Mongoloid 2.68 x humerus + 83.19 ± 4.16 cm (Use Male)
Ulna
Caucasoid 3.76 x ulna + 75.55 ± 4.72 cm 4.27 x ulna + 57.76 ± 4.30 cm
Negroid 3.20 x ulna + 82.77 ± 4.74 cm 3.31 x ulna + 75.38 ± 4.83 cm
Mongoloid 3.48 x ulna + 77.45 ± 4.66 cm (Use Male)
Radius
Caucasoid 3.79 x radius + 79.42 ± 4.66 cm 4.74 x radius + 54.93 ± 4.24 cm
Negroid 3.32 x radius + 85.43 ± 4.57 cm 3.67 x radius + 71.79 ± 4.59 cm
Mongoloid 3.54 x radius + 82.00 ± 4.60 cm (Use Male)
5. Other Information We Can Get
From Bones:
• Evidence of trauma (here
GSW to the head)
• Evidence of post mortem
trauma (here the head of
the femur was chewed
off by a carnivore)
http://library.med.utah.edu/kw/osteo/forensics/index.html
Medial Imposition
Sculpting By Angela Janick
What if this is all you have?
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Facial Reconstruction
• Determine demographic information
(female, Caucasian, early 40s)
• Note unique features
(had lost all back teeth on
upper and lower jaw)
• Anything known about this individual?
(came to U.S. by boat in 1710
from Europe, died and buried in
NY around 1733)
1. Obtain skull
Facial Reconstruction
2. Add tissue depth markers
• Based largely on sex and race
3. Begin to add common fat deposits
and underlying muscles
Facial Reconstruction
4. Add muscle to average
depth for race
5. Add skin, nose, ears
6. Add features related to age and race
(wrinkles, eye and hair color)
Facial Reconstruction
7. Add clothing etc appropriate for the
time period, religious affiliations, etc
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Forensic Anthropology and
Odontology
Human Bone vs. Animal Bone
• Macroscopic differences
• Radiology
• Observation
• Measurement
• Microscopic differences
CHE 113 69
Macroscopic differences
Baboon femur Human femur
Microscopic differences
Spongy bone
human
mouse
CHE 113 71
Other information TRAUMA and PATHOLOGIES
Ante- mortem
Post-mortem
Peri-mortem
Gunshot
CHE 113 72
Trauma
Individual Identification
Person identified when it
was found that the
amalgam used in her
dental restorations was of
a type found only in
specific areas on the
Eastern Coast of the
United States.
Habitual activity can wear away the
protective, cartilagenous lining which
reduces friction in joints. The humerus
in this photograph were in contact for
many years prior to this individual's
death. The surfaces are smooth and
shiny, indicating that the joint capsule
and cartilage had worn away, allowing
bone on bone contact in the cavity.