OSTEOMETRY; THE MEASUREMENT OF THE BONES . 83 

 Clavicle 



I. MEASUREMENTS 



1. Maximum length;* taken with the osteometric board. 



2. Girth; taken at the middle of the shaft. 



3. The two angles of curvature; These are taken upon the dioptograph 

 tracing of the contour of the bone from above, oriented as this is done by 

 having the two borders of the acromial third in the same plane, hori- 

 zontally placed. 



The middle axis of the bone is traced, following the curves, and 

 beginning and ending in the center of the two ends; the points where 

 the line attains the farthest point anteriorly and posteriorly are then 



FIG. 30. Right clavicle, from above, showing measurements. This figure is based 

 upon several by Parsons, and represents the average measurements obtained from 

 70 English males. 



marked, and lines drawn, connecting these with the middle of the two 

 ends and with each other. These form a medial angle, projecting forward 

 and a lateral, projecting backward. These can be measured with a 

 protractor. Added together they form the "index of curvature. " These 

 may be directly compared. 



4. Breadths, taken from the dioptograph tracing; Parsons uses five 

 of these; at the two ends, at the inner angle, at the narrowest place, and 

 at the conoid tubercle. 



* PARSONS: Engl. Journ. Anat., 1917, found the average length of English clavicles, 

 taken from the lower and lower middle classes to be: 



males, right (70) 151 mm. 



males, left (83) 153 



females, right (65) 138 



females, left (64) 138 



The above were separate clavicles, taken at random; when the two clavicles of the 

 same individual are taken in the cadaver, and compared with the total shoulder- 

 vridth (not bi-acromial) PARSONS found, in 50 male bodies, the length of the right 

 clavicle to average .382 of the shoulder-width, and that of the left, .387. In 49 female 

 bodies the respective figures were .380 and .383, thus showing more definitely the 

 greater length of the left clavicles in both sexes. 



