ABSTRACT
Normal bone is subjected to continual loads which are supported by means of forces. Changes to normal loads have to be countered by forces with equal and opposite force. These forces include tension (axial force), compression (axial force), shear, bending, and flexure, (torsion). It may be helpful to think of bone as a wall made up of bricks and mortar (see schematics shown in Figures 1.7-1.10). The bricks represent the mineral component of bone and the mortar represents collagen. An axial load is the load produced by pushing on the ends of long bones. The direction of gravity as well as the structure of the skeletal system and pull of muscles results in long bones being subjected to loads orientated along the long axial, hence, these are referred to as axial loads. One can liken this to a force pushing down on the wall (Figure 1.7).
