Distribution of osteonic and interstitial components in the human femoral shaft with reference to structure, calcification and mechanical properties

This paper analyzes the distribution of osteons and interstitial bone in the femoral compacta according to their structure, degree of calcification and mechanical properties. Three cross sections, 100 μm thick, each located 1 cm from the next, were prepared by grinding from the middle third of a human femoral shaft. Starting from the premise that in lamellar bone, lamellae whose fiber bundles and crystallites have a longitudinal course withstand loading by tension, whereas those whose fiber bundles and crystallites have a transversal course withstand loading by compression, each osteon and fragment of interstitial bone has been given a number recording the percentage of its surface consisting of lamellae with transversally oriented fiber bundles and crystallites (bright under the polarizing microscope). The degree of calcification of the same structures was determined microradiographically. The distribution of both osteons and interstitial bone was assessed using a tungsten grid for reference. The total surface of each bone microstructure, and the percentage of that surface consisting of bright lamellae, were all calculated using a Zeiss Videoplan. Our results confirm the view that the distribution of both osteons and interstitial bone is mainly related to their structure - and hence to their mechanical properties. In addition, bone remodeling seems to be most active in areas capable of supporting tensile stress

Collagen orientation in compact bone: I. A new method for the determination of the proportion of collagen parallel to the plane of compact bone sections

[No abstract available

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 corss-sections, 100 μm 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 insterstitial 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