Pole Figures of the Orientation of Apatite in Bones

Abstract

THE orientation of the apatite and collagen in bone was first considered in this work because of its significance in the possible piezoelectric effect in bone. Bone is a polycrystalline material composed chiefly of apatite and collagen, and crystals of a component must be both piezoelectric and orientated in order to produce an overall piezoelectric effect. Orientation studies are also important for an understanding of the mechanical properties and anisotropic characteristics of bone as a structural material. Biologically, bone is a tissue composed of lamellae, blood, bone cells and fluids in a continual state of change. Within this biological system, however, could be a three dimensional network of apatite and collagen on a much smaller scale, which would maintain the mechanical properties of the bone at a constant level, irrespective of the normal sequence of biological changes. This work shows that such a highly organized three dimensional mesh of apatite crystals does exist, and that the exact structure of the mesh in a particular bone may be related to the function of that bone.