Three-dimensional organization of the cartilage canal--a scanning electron-microscopic study by vascular cast of the rabbit's femoral head.

The microvasculature of the cartilage canal was studied by plastic corrosion casting using a scanning electron microscopic (S.E.M.) method. At the 25th fetal day, the vascular architecture of the cartilage canal showed an unbranched channel terminated by dividing into a capillary glomerulus. In the later embryonic stage, the canals dilated throughout their course. At birth, before the appearance of the secondary center of ossification, the chondroepiphysis was well vascularized. Anastomosis between the epiphysis and the metaphysis preceded the occurrence of ossification. During the growth stage, the ossifying center was enlarging, the canals extended to the metaphyseal side more frequently than to the articular side. The communicating canals which had traversed the physis faded gradually. In the adult stage, the ossification center had developed completely. The cartilage canals on the surface of the ossification center disappeared. These results show that the cartilage canal has a significant role in the nutrition of the epiphysis and in the osteogenesis of secondary centers of ossification.