Bone collagen structure in normal and pathological tissues is presented using techniques of
thin section transmission electron microscopy and morphometry. In pathological tissue,
deviations from normal fine structure are reflected in abnormal arrangements of collagen
fibrils and abnormalities in fibril diameter. The relationships between these bone structural
changes and the skeletal calcium/phosphorus ratio are discussed. Calcium/phosphorus
ratio is measured by X-ray absorptiometry and computed microtomography.