Age changes in human bone: a microradiographic and histological study of subperiosteal and periosteal calcifications.

Age changes in subperiosteal areas of human bones are described in 56 subjects of both sexes aged 18-96 years, using microradiographic and histological analysis of thick undecalcified sections from the midshaft of the femur, the tibia, the third metacarpal bone and the third rib. Till the age of 39, most areas of the subperiosteal bone consist of circumferential fundamental lamellae. From the age of 48, certain areas of the subperiosteal bone appear hypercalcified, while in others mineral precipitations occur in the inner layer of the periosteum close to the bone cortex, involving the deep periosteal fibers. These periosteal calcifications should partially account for the increase in transverse diameter of bones throughout adult life.