182 JOHN C. KOCH 



shown pictures of the inner architecture of many bones, includ- 

 ing the tibia, femur and humerus. But evidently he understood 

 little of the reasons underlying the arrangement of the cancelli 

 as he describes the head of the femur as consisting of a reticular 

 bony substance. 



Not until 1832 was the problem of the mechanics of the inner 

 architecture of bone undertaken. In that year, Bourgery pub- 

 lished an anatomy, illustrated by Jacob, in which the inner 

 structure of the femur, tibia, humerus and other bones is deline- 

 ated with wonderful accuracy. The illustrations are almost as 

 accurate in detail as photographs, but the written descriptions 

 and the interpretation of the inner architecture are very much 

 in error. 



Ward ('38), an English anatomist, seems to have been the 

 first writer to grasp, even partially, the real significance of the 

 over-hanging head of the femiu" and to see any relation between 

 the external form and the arrangement of the cancelli within 

 the bone. His conception of the arrangement of the cancelli 

 in the head of the femur was that they were arranged in straight 

 lines to support the over-hanging load of the femur much as a 

 load is supported by a derrick, where the vertical mast has a 

 cable running from its top to the inclined boom at whose upper 

 end the load is suspended. The stresses in the cable are ten- 

 sile and in the boom compressive : in like manner, Ward assumed 

 that cancelli run from the axis of the shaft of the femur near the 

 top horizontally, or nearly so, to connect with the sharply in- 

 clined lines nearly vertical, that run from the articular surface 

 of the head of the femur to end in the medial part of the shaft. 



Jefferies Wyman, an American anatomist, in a paper communi- 

 cated in 1849, but not published until 1857, advanced the theory 

 of the inner architecture of the femur considerably by analyzing 

 the cancelli of the femur, as seen in frontal section, into three 

 groups: a tensile group, rising from the lateral (outer) portion 

 of the shaft and crossing high in curves to reach about the middle 

 of the head of the femur; a compressive group, rising from the 

 medial portion of the shaft and proceeding radially as straight 

 lines upward to reach either the articular surface of the head, 



