222 JOHN C. KOCH 



and weighed 200 pounds. At the time of death he was in 

 splendid physical condition. 



It is evident that the inner architecture of the femurs from 

 such a subject truly represents the structures in the normal 

 living individual. For this reason, it is believed that the data 

 derived from this study represent the true quantitative rela- 

 tions and actual mechanical conditions that exist in the nor- 

 mal individual. It is recognized that individual variations 

 occur, depending upon age, sex, occupation, body weight, etc. 



The data derived from the study of a single specimen are 

 always subject to the criticism that it was unusual in some 

 respect. In order to be as certain as possible that the shape and 

 general arrangement of the inner architecture of the specimens 

 analyzed were not exceptional, they have been compared with 

 about 30 femurs obtained from the dissecting-room. From 

 such comparison of the general form of the bone and of the 

 inner structure of various longitudinal and cross sections made 

 through similar planes in the specimens examined, I am certain 

 that the two femurs (from the same subject) analyzed in this 

 paper are typical, normal femurs. 



Longitudinal serial frontal sections were made of the left 

 femur and serial transverse sections of the right one, the details 

 of which will be taken up in subsequent paragraphs. 



The femur as a structure 



1. General. It has been shown in Part II that human bone 

 when subjected to loading acts as do other elastic bodies, and 

 therefore, it conforms to the laws of mechanics which govern the 

 action of elastic bodies under stress. 



From a mechanical point of view the femur is seen to be a 

 long, slender column whose upper extremity is bent at a con- 

 siderable angle to the shaft. Figure 14 is an accurate outline 

 drawing of a longitudinal section through a normal femur, cut 

 in such a manner as to pass through the axis of the bone and in 

 a plane approximately vertical, the femur being considered in 

 the position normally assumed in the standing, erect attitude. 



