The calcified zone (basal layer) of articular cartilage of rabbits

In the mammalian embryo, the articular end of a long bone consists of a mass of fetal cartilage which undergoes transformation into two types of tissue as the animal ages: The hyaline cartilage surface of the adjacent joint; and the bone of the ossific nucleus of the epiphysis. The junction of these two areas, the calcified zone (or basal layer) of the articular cartilage, was studied in the distal femur of 110 albino rabbits of various ages by: tritiated thymidine autoradiography; routine histologic staining and mitotic counts; special stain for glycogen; and special stain for calcium (murexide).