OSTEOMETRY; THE MEASUREMENT OF THE BONES 99 



for which the average of 25 separate radii is 237.3 mm.* Next follows 

 the negro races, with an average of 235 to 238. Among other races 

 are the following averages; although they rest upon too few single cases 

 to be final: Australians, 227.3; Melanesians, 226.4; Polynesians, 210.3; 

 Japanese, 200; Negritoes, 194.7. The physiological length of the 

 Neandertal right radius is 225. 



The Simian apes, with their notably long forearm, naturally show 

 longer absolute figures than does even the largest man. Thus, for the 

 gorilla we have 302.4; for the chimpanzee, 266; for the orang-utan 334.3; 

 and for the gibbon, in spite of its small size, 257.8. 



Several of the older anthropometrists, notably Turner, used a com- 

 parison of the lengths of humerus and radius to form a Radio-humeral 

 index, in which the length of the humerus was taken as the standard 

 (= 100), and the (anatomical) length of the radius compared with it. 

 This evidently grew out of the still earlier observation on the relative 

 lengths of the forearm and upper arm, which formed the starting point 

 of the anthropometry of the limbs, as given in the Introduction. This 

 may be recorded here. 



max. length of radius X 100 



3. Humero-radial index; 



max. length of humerus 



II. SHAPE AND PROPORTIONS OF SHAFT 



4. Least circumference of the distal half. Most usually that circum- 

 ference of a long bone which is selected for comparison with the length 

 in estimating its proportionate caliber is the least one that can be found, 

 which, in the case of most bones, is a fairly definite point. In the radius, 

 however, there are three small places. (1) The "neck," between capitel- 

 lum and bicipital tuberosity, (2) a point a little below this latter, and 

 (3) a point just beyond the middle of the shaft, towards its distal end. 

 In some bones one of these, and in others another, may prove to be the 

 least circumference, so that, in order to be uniform, one must be desig- 

 nated as the one to use. The best for many reasons, and in more than 

 half the cases the actually smallest place, is the last named, which may 

 be definitely designated as the point to be measured. As in all circum- 

 ferences the measure is taken by means of the tape. 



, , . _, least circumference (4) X 100 



5. Caliber index (4:2) = - r = = = n -, , . 



physiological length (2) 



This index expresses the degree of slenderness of the bone as a whole, 

 the less the figure the more slender the bone. The following table 

 shows that in general the radius is especially slender in the lower Primates, 

 stouter in the Simian apes, and in the lower human races, and in the 

 culture races the stoutest of all. The orang and gibbon, however, with 



* LEHMANN-NITSCHE : Untersuchungen iiber die langen Knochen der siidbayer. 

 Reihengraberbevolkerung. Beitr. zur Anthropol. und Urgeschichte Bayerns. 

 Bd. 9, Munchen, 1895. This is also excellent for the other long bones of the skeleton. 



