Orientation of Apatite Crystals in Bone

Abstract

FROM the earliest experiments on X-ray diffraction by specimens of bone, it has been well known that in long bones, for example, femora, the c-axes of the hexagonal apatite crystals are preferentially orientated parallel to the long axis of the bone. In regard to sections of bones cut normal to the long axis, no one has reported any preferential orientation of the crystals. In fact, it has been repeatedly stated in the literature that there is no orientation of the crystals in the plane perpendicular to the long axis¹.