ABSTRACT
Fractographic aspects of bone have always been examined in the same manner as for other engineering materials. The great difference is the fact that bone is a living tissue. Bone has also an ability to adapt itself to the externally imposed environment; thus bones of athletes are thicker and stronger, but bones of old people or people confined to bed become thinner because they are not required to transmit the high stresses of a young and active adult. Bones are structural components of the body and transmit predominantly compressive, torsional, and bending stresses. Trabecular bone, which has a cellular, porous structure and is often referred to as cancellous or spongy bone, is designed primarily to absorb energy and transmit compressive stresses. Bone is a highly anisotropic material, on both microstructural and submicrostructural levels; consequently it is only logical that the energy to propagate a crack and the mechanisms of crack propagation depends on the spacial orientation of a test specimen.
