NEW ATTEMPT AT THE INTERPRETATION OF THE FUNCTIONAL ARCHITECTURE OF THE CANCELLOUS BONE

The author's theory explains the development mechanisms of the functional structure of cancellous bone. Functional, secondary cancellous bone develops from the primary growth-dependent cancellous lattice under the influence of multidirectional loading. The primary cancellous bone is remodelled according to the general strain-dependent mechanism of the functional adaptation of bone. Oblique loading of the metaphysis in extreme positions in the joint evokes the greatest strain in the bone trabeculae oriented in these oblique directions, as demonstrated by calculation on a simple three-beam model. All trabeculae are therefore remodelled in these directions resulting in a typical picture of two crossed pressure systems. Each of them corresponds to one of the extreme loading directions. Tensile systems can be found only in places of ligament or tendon insertions or under concave joint surfaces.