The arterial supply of the proximal end of the human femur in 100 specimens ranging in age from newborn to 67 years were studied by perfusion method. A complete extracapsular anastomotic ring, formed by both the medial and the lateral femoral circumflex arteries, was present surrounding the base of the femoral neck in 71％. An incomplete subsynovial intraarticular anastomotic ring, formed by the four ascending cervical arterial groups (medial, posterior, lateral and anterior), was present at the margin of the articular cartilage in 74％ of the specimens. There might be defect at anterior, posterior or both aspects. The lateral epiphyseal arteries, giving off many multiarcaded branches towards the articular cartilage, supplied the superior, medial, central and the lateral parts of the head. The medial ascending cervical arteries supplied the infero-posterior part of the head. The medial epiphyseal arteries supplied a limited subfoveal area. The nutrition of the free surface of the articular cartilage was derived from the vascular networks in the synovial membrane near the periphery of the articular cartilage and the fovea capitis femoris, and from the synovial fluid. The nutrition of its deep part near the chondro-osseous junction was derived from the looped epiphyseal capillaries. The superior metaphyseal arteries supplied the lateral two thirds of the neck. The medial, anterior and posterior ascending short cervical arteries supplied the corresponding areas of the neck. During the ossification of the chondroepiphysis the medial and lateral epiphyseal vessels and the medial ascending cervical artery established particular vascular anastomotic arch in the epiphysis. With epiphyseal plate closure in the adult the diaphyseal arteries crossed into the head, established free anastomoses with the epiphyseal arteries. The clinical significance of the topographical characteristics, the course and the distribution of the arterial supply to the proximal end of the femur were discussed.

The arterial supply of the lower end of the human femur in 100 specimens, ranging in age from the newborn to 87 years, was studied by the perfusion method. Its blood supply is derived from the medial and lateral superior genicular arteries, the descending genicular artery and the middle genicular artery. A complete extracapsular anastomotic ring, surrounding the supracondylar portion of the lower end of the femur, is formed by the medial and lateral superior genicular arteries and the descending genicular artery in 55?4.97%. Its incomplete anterior part is linked by the periosteal arterial network in 45?4.97%. The vessels at the metaphyseal side of the growth plate end in a brush-like pattern, intimately connected to the hypertrophic layer of cells of the growth plate, each vessel turning back in a sharp loop. The anterior and posterior metaphyseal arteries which arise from the extracapsular anastomotic ring and network supply the supracondylar area. The medial and lateral epiphyseal arteries, arising respectively from the descending genicular artery and both superior genicular arteries, supply the medial part of the medial condyle and the lateral part of the lateral condyle. The anterior and intercondylar epiphyseal arteries, arising respectively from the periosteal network and the mildle genicular artery, supply the intercondylar area. The epiphyseal arteries which anastomose with each other in the ossific area of the epiphysis form the precapillaries and capillary network. The anastomotic branches between the epiphyseal arteries, ranging from 25 to 100 microns in diameter, form the arterial plexus in the epiphysis. With the closure of the epiphyseal plate, a free anastomosis is established between the metaphyseal and the epiphyseal vessels. The clinical significance of the topographical characteristics, the course and the distribution of the arterial supply to the lower end of the femur were discussed.

The arterial supply of the human tibia in 50 specimens, ranging in age from 4 to 87 years, has been studied by the arterial perfusion method. The tibia is supplied principally by branches of the anterior and posterior tibial arteries and the peroneal artery, with additional contributions from the inferior genicular arteries, the middle genicular artery and from the infrapatellar branch of the descending genicular artery. There is a continuous arterial anastomosis in the periosteal network on the non-articular surface of the tibia. The segmental periosteal ring arteries dividing into ascending and descending branches, connect with the branches from above and below to form the longitudinal anastomoses along the anterior, medial and the lower one-third of lateral tibial borders. The epiphyseal-metaphyseal regions are copiously supplied by vessels entering from the periphery and by the nutrient artery. With the fusion of the epiphyseal plate, a free anastomosis is established between the epiphyseal and metaphyseal nutrient vessels. The whole of the marrow and the inner two-thirds or three-quarters of its cortex are supplied by the nutrient artery. The outer third or fourth of the cortex is supplied by the periosteal vessels. Because the cortical longitudinal and transverse capillary systems are profusely anastomosed with each other and with the periosteal and endosteal circulatory networks, the blood can flow in either direction, depending on physiological conditions.The clinical significance of the arterial distribution to the tibia is briefly discussed.