Techniaue Review

Part One of Two

AtlasOrthogonal

Mastoid SupportAtlas-Cephalic Acute Angle

by Roy W. Sweat, D.C.

About the Author. Dr. Roy W Sweat'spractice is in Atlanta, Georgia. He is agraduate of Palmer College. In 1952,he began a course of study specializingin the upper cervical occipital-atlanto-axial complex under Dr. John F.Grostic. Dr. Grostic chose him as aninstructor at his seminars. Sweatcompleted a three-year program inchiropractic orthopedics from theNational College. He is an associateprofessor at Life College.

Dr. Sweat designed the cervicalanalysis instrument. In 1981 he cre-ated the program of chiropractic AtlasOrthogonality and wrote a series offive books. Dr. Sweat has designed achiropractic adjusting instrument andalso a series of x-ray analysis instru-ments and attachments for the x-raymachines and the orthogonal ad-justing tables.

Dr. c.H. Suh, Ph.D., of the Univer-sity of Colorado has again chosen Dr.Sweat to speak at the Annual BioMechanics Conference (14th) on thespine. Dr. Sweat's orthogonal pro-grams have also been approved bythe CCE(Canada) through the Cana-dian Memorial Chiropractic College.

The center skull line ismeasuredfrom vertical and, in relation-ship to, the atlas plane line.When the atlas moves laterally

on the occipital condyles, the centerskullline and the atlas plane line will

Today', Chiropractic/November-December 1983

create an acute angle on the side oflaterality. We always adjust on theside of the acute angle to move theatlas around the occipital condyle toreturn it to it's neutral position underthe foraman magnum.

All of the line of drive factors aredesigned to return the cranium tovertical, the atlas plane line to hori-zontal, and the cervical spine tovertical. It is possible to adjust lowplane lines on the opposite side of theacute angle and return the atlas planeline to neutral and the cervical spineto vertical, but it will not remove theacute angle between the occipitalcondyle and the atlas.

Positive Mastoid SupportThe mastoid is circular, shaped

similar to a spoon, and can vary fromten degrees from vertical to sixty de-grees. The mastoid is our most directsupport for the occipital condyles.The inferior tip of the mastoid must besupported to prevent the head frommoving when the adjustment is given(Fig. 1).

When the mastoid is not supportedand the support is under the center ofthe head three to four inches abovethe occipital condyle and the atlas,this means we have an anchored pointat the shoulders and the middle of thehead. This creates a pinching or closingeffect on the occipital condyles andthe superior facets of the atlas. Thiscloses the articulation that we are at-

tempting to move within their articularbeds.

When the shoulder and the middleof the head are supported and themastoid is unsupported, this creates afloating effect between the occipitalcondyles and the atlas facets. Whendriving a nail in the center of a boardwith the supports on each end of theboard, as the hammer hits the nail theboard will deflect down and receivesmuch of the energy. This causes akinetic- reaction which will cause theboard to spring back upward.

As we move the support as close tothe nail as possible, the board becomesmore static in it's reaction, causing littleor no movement, thus, all the energyis then received by the nail (Fig. 2).This same principle holds true for theoccipital condyles and the atlas. Whenthe mastoid does not have a positivesupport, there is an excess of move-ment in the sub-occipital area whichwill put more stress and strain on thesub-occipital muscles. There is a de-flection action which creates an exces-sive amount of movement in the entirecranial-cervical area.

As stated in my previous article,most authorities agree that there is anaverage of five degrees of lateralmovement between the occipital con-dyle and the superior atlas facets.Ninety percent of the condylar circlesare three to four inches in diameter.With a three-inch diameter, a 1Y2-inchradius and five degree movement on

23

, I

Fig. 1

INCORRECT

Fig. 3

Fig. 2

INCORRECT

:'0.' :...::., '( , ;!

CORRECT

Fig. 4

a 1t"2-inch radius will equal Y1I-inchlineal movement. So, the maximummovement between the occipitalcondyles and the superior atlas facetwill average Y1I-inch.

Rocking The HeadIn the cervical analysis, the cranium

is related to having moved from ver-tical, which means that in the standingposition the cranium has moved fromthe vertical position and is leaning tothe right or left toward the feet. Whenthe patient is placed on a side posturetable, the head has moved from ver-tical and is leaning toward the feet.When the adjustment is hard or force-ful, or with no mastoid support, andthe head rocks more toward the feetduring the adjustment the head is thenbeing taken farther from vertical whichwill increase its disrelationsbip to theatlas, or will remain in its disrelation-ship with the atlas as they both rocktoward the feet together (Fig. 3).

Sometimes this willlower atlas planelines and reduce opposite lower angles,but willnot remove or reduce the acuteangle between the cranium and theatlas. Thus, when adjusting with the

24

cervical spine angle on the same sideas the upper cephalic angle, it canincrease the lower angle, making itmove more from vertical. The headshould always remain stationary asthe atlas moves around the occipitalcondyles and, in some subluxationswhen the lower angle is on the sameside as the laterality, the headpiece isset at a steeper angle with the tip ofthe mastoid still being supported butwith less of the mastoid being sup-ported so that the weight of the head,which is nine to fourteen pounds,creates a gravitational pull toward thefloor to help prevent the head fromrocking downward and giving themechanical advantage of the condylesmoving upward as the atlas movesdown and around the condyle.

The occipital condyles are used as afulcrum to move the cervical spine. Ifthe mastoid moves, the head movesand this moves the occipital condylesand you lose the mechanical advant-age of fulcrums and levers.

Table Support DirectlyUnder The Mastoid

The old Grostic tables had a scissors-

type mechanism to raise and lowerthe table. Raising the table, they werequite satisfactory, but, when loweringthe table, the scissors would remainup and the doctor had to press hishand down on the mastoid supportbefore the adjustment to make surethere was no loose movement in theheadpiece. The mastoid support wasdistended and acted as a cantileverwith the support not directly underthe mastoid itself. Dr. Hugh Crowedesigned our headpiece by movingthe support rod directly under themastoid to make the support firmerand without any loose movement (Fig.4).

In his article titled "Head Pieces forSide-Posture Adjusting", Dr. Hugh LCrowe states. . ."We found that with aproper mastoid support, a moreshallow adjustment would reduce the.subluxation. It was also found thatsome of the mastoid supports beinginstalled on new tables were too softand too rounded. It was then that, incooperation with Dr. Roy Sweat, westarted to replace some of these defec-tive supports trying to improve on thedesign of the old mastoid support. ".

Today', Chiropractic/November-December1983