[Mineralization at the level of the calcified cartilage zone. Value and significance of the spicule of calcification].

The calcified cartilaginous spicule, generated in the zone of the calcified cartilage, is included in the primary metaphysis. It is generally admitted that the spicule had a homogeneous structure. Studies of structure and ultrastructure of the calcified spicule made the existence of two definitely different zones obvious: one at the periphery of the spicule, the other in the center. The process of mineralization, noticed on the cartilaginous column, reveals that vesicules are at the origin of mineralization of the peripheral zone and that mineralization of the central zone involves the granules of proteoglycans more particularly.