The micromechanics versus the macromechanics of cortical bone--a comprehensive presentation.

Secondary cortical bone is a complicated patchwork of structures which can be viewed as a hierarchy of four different orders. As far as the biomechanical properties of cortical bone are concerned, the lamellae is the most important of the four. The relative distribution of longitudinal lamellae (whose fiber bundles and crystallites have a longitudinal course and withstand loading by tension) with respect to transverse lamellae (whose fiber bundles and crystallites have a transverse course and withstand loading by compression) governs the mechanical properties of bone at macroscopic level both in normal and pathological conditions.