| Abstract: | New techniques in bone mechanics, and the demonstration that locomotor function can be interpreted based on patterns of structural strength delineated by these new techniques, lay the foundation for analyses of structural strength in nonhuman primate long bones. The present paper details topographic variability in structural strength of the femoral diaphysis of Macaca as a basis for further quantifying form-function interactions in pronograde primates. The femoral diaphyses of 42 macaques were serially sectioned. These sections were digitized, and coordinate points were submitted to the SCADS computerized stress analysis program. This analysis indicated that the femoral diaphysis of Macaca is better adapted proximally than distally to resist axial loads. The proximal third of the femur is better able to resist bending loads in the posterolateral/anteromedial direction than in the standard planes. The distal femur is geometrically well suited to resist high bending loads, particularly in the mediolateral plane. The elliptical construction of the distal femur is designed to resist high torsional loads as well. When compared with density data on the macaque femoral diaphysis, these data indicate extremely high rigidity in the mediolateral plane. The inverse relationship between density and structural rigidity distally indicates the presence of compensatory mechanisms between structural strength, geometry, and density. Similarities in femoral mechanics in macaques and humans suggest uniformity of stress patterns of the lower extremity in terrestrial quadrupedal and bipedal locomotion. |
