The Beautiful Mechanics of the Body

The Architecture of the Femur.—Koch , by mathematical analysis has “shown that in every part of the femur there is a remarkable adaptation of the inner structure of the bone to the machanical requirements due to the load on the femur-head. The various parts of the femur taken together form a single mechanical structure wonderfully well-adapted for the efficient, economical transmission of the loads from the acetabulum to the tibia; a structure in which every element contributes its modicum of strength in the manner required by theoretical mechanics for maximum efficiency.” “The internal structure is everywhere so formed as to provide in an efficient manner for all the internal stresses which occur due to the load on the femur-head. Throughout the femur, with the load on the femur-head, the bony material is arranged in the paths of the maximum internal stresses, which are thereby resisted with the greatest efficiency, and hence with maximum economy of material.” “The conclusion is inevitable that the inner structure and outer form of the femur are governed by the conditions of maximum stress to which the bone is subjected normally by the preponderant load on the femur-head; that is, by the body weight transmitted to the femur-head through the acetabulum.” “The femur obeys the mechanical laws that govern other elastic bodies under stress; the relation between the computed internal stresses due to the load on the femur-head, and the internal structure of the different portions of the femur is in very close agreement with the theoretical relations that should exist between stress and structure for maximum economy and efficiency; and, therefore, it is believed that the following laws of bone structure have been demonstrated for the femur:	17
“1. The inner structure and external form of human bone are closely adapted to the mechanical conditions existing at every point in the bone.	18
“2. The inner architecture of normal bone is determined by definite and exact requirements of mathematical and mechanical laws to produce a maximum of strength with a minimum of material.”