Collagen orientation in compact bone: II. Distribution of lamellae in the whole of the human femoral shaft with reference to its mechanical properties.

Starting from a previous personal investigation (Portigliatti Barbos et al., 1983) indicating that the distribution of osteons and interstitial bone in the middle of the femoral shaft is related to their structure, a new procedure has been devised to allow information of the same kind to be gathered from the whole of the femoral diaphysis. Twenty-three exactly plane parallel cross-sections, 100 micron thick, each located 1 cm from the next, were prepared using an annular blade microtome. The distribution of longitudinal lamellae (whose fiber bundles and crystallites have longitudinal course and withstand loading by tension) and transverse lamellae (whose fiber bundles and crystallites have a transverse course and withstand loading by compression) was determined for both osteonic and interstitial bone, using circularly polarized light as the illuminating source and a Quantimet 720 image analyzing computer. The results show that along the femoral shaft the transverse and longitudinal lamellae from osteonic and interstitial bone have a characteristic rotational distribution consistent with the distribution of the bending forces normally operative in bone.