Fig. 1

A, Normal growth plate morphology. Proliferating chondrocytes undergo hypertrophy, then apoptosis to become the primary spongiosum of bone. B, Abnormal growth plate in a case of metatropic dysplasia. Hypertrophic chondrocytes irregularly extend into the primary spongiosum, disturbing the normal architecture (arrow). C, Growth plate chondrocytes from a patient with diastrophic dysplasia demonstrating characteristic rings around the chondrocytes (arrow). P, proliferating chondrocyte; H, hypertrophic chondrocyte; B, bone; PS, primary spongiosum.