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HANDBOOK OF PHYSIOLOGY 



CIRCULATION II 



PRINCIPAL NUTRIENT 

 ARTERY AND VEIN 



PERIOSTEAL CAPILLARIES - 

 IN CONTINUITY WITH ' 

 CORTICAL CAPILLARIES 



other hand, Trueta & Harrison (107) 

 believe that in the adult human femur 

 the nutrient artery does not reach the 

 metaphyseal region which is wholly sup- 

 plied by metaphyseal arteries. Studies 

 on rabbit embrvos and young rabbits metaphyseal arteries 



AND TERMINALS OF THE 



indicate that in the earliest stages of de- medullary arterial 



SYSTEM ^«^ 



velopment the metaphysis receives blood 

 only from the nutrient artery. Later, 

 metaphyseal arteries derived from the 

 periosteum take over the supply of the 

 peripheral region, the extent of the area 

 supplied bv them increasing progres- 

 sively (85). 



The arteries supplying the proximal 

 part of the femur and the acetabulum 

 are the lateral femoral circumflex, the 

 medial femoral circumflex, the obtu- 

 rator, the superior gluteal, the inferior 

 gluteal, the first perforating artery, and 

 the nutrient artery of the femur (62). 

 Branches of these enter the head and 

 neck of the femur through small foram- 

 ina, or enter by way of the fovea cen- 

 tralis, or are carried to the head of the 

 femur in the ligamentum teres. 



In children the foveal vessels assume 

 a small role in supplying blood to the 

 femoral head (108, 114). When these 

 arteries do penetrate to the ossification 

 center they are probably supplemen- 

 tary (62). In the adult the foveal ar- 

 teries are larger and usually nourish the 

 femur. Apparently, arteries enter the 



femoral head through the ligamentum section. [From Brookes (13).] 

 teres in the majority of cases (108, 1 14), 

 but this supply is supplementary to the vital supply 

 from the capital arteries (62). 



All investigators have emphasized the importance 

 of the capital branches of the medial femoral circum- 

 flex artery for the nutrition of the femoral head (109). 

 The terminal branches enter the femoral head at the 

 articular rim, just posterior to the superior and in- 

 ferior poles of the femoral neck. Most investigators 

 have found that the superior posterior branches are 

 larger and more numerous than the inferior posterior 

 arteries. Usually, no arteries enter the femoral head 

 or neck anteriorly (109). The nutrient artery cannot 

 be traced past the marrow cavity (62). 



Vessels enter the distal end of the femur through 

 three groups of foramina: supracondylar, condylar, 

 and intercondylar (99). In each some 10 to 35 for- 



END-ARTERIAL 

 TERMINALS 



VENOUS SINUSOIDS V 

 .--'METAPHYSEAL VEINS 



MEDULLARY 

 SINUSOIDS 



INTERFASCICULAR 

 CAPILLARIES IN MUSCLE 



CENTRAL VENOUS 

 CHANNEL 



LARGE EMISSARY VEIN 



TRANSVERSE EPIPHYSEAL 

 VENOUS CHANNEL 



fig. i . Diagram of vascular organization of rat tubular bone in longitudinal 



amina are present. Condylar arteries perforate the 

 cortex and ramify within the spongiosa. Terminal 

 branches of the middle geniculate arteries pass 

 through the intercondylar foramina and are distribu- 

 ted to the central parts of the epiphysis. Rami arising 

 from the superior, lateral, and middle geniculate 

 arteries pass through the anterior and posterior 

 supracondylar nutrient foramina, and are distributed 

 to the distal end of the diaphysis. The generous vascu- 

 lar supply explains the lack of ischemic necrosis after 

 fractures of the lower end of the femur. 



The blood supply to the cortex or compactum of 

 long bones runs in longitudinal canals known as 

 Haversian canals. In man the canals vary from 25 to 

 125, averaging 50 yu in diameter, but larger ones are 

 also seen (70). Although these canals run longitudi- 



