THE POPLITEAL ARTERY 621 



of loops by anastomosing with one another (fig. 497), and with the superior gluteal, medial cir- 

 cumflex, and inferior gluteal arteries above, and with the muscular and articular branches of the 

 pophteal below. They are distributed chiefly to the hamstring muscles, but send twigs along 

 the lateral intermuscular septum to supply the integuments at the back and lateral parts of the 

 thigh. Other branches perforate the lateral intermuscular septum and the short head of the 

 biceps, and, entering the vastus intermedins (crureus) and vastus laterahs, anastomose with the 

 descending branch of the lateral circumflex. AU the perforating arteries, moreover, contribute 

 to reinforce the artery of the sciatic nerve, a branch of the inferior gluteal (sciatic) artery. They 

 are each accompanied by two veins which terminate in the profunda. 



The first perforating artery [a. perforans prima] is given off from the profunda as that vessel 

 sinks beneath the adductor longus. It either pierces the adductor brevis, or else runs between 

 the pectineus and adductor brevis, and then passes through a small aponeurotic opening in the 

 adductor magnua close to the medial hp of the linea aspera. In this course it supplies branches 

 to the adductors, and, after perforating the adductor magnus, is distributed to the lower part of 

 the gluteus maximus and the hamstring muscles, one branch commonly running upward beneath 

 the gluteus maximus to anastomose with the lateral circumflex, medial circumflex, and inferior 

 gluteal (sciatic) arteries, forming the crucial anastomosis at the junction of the neck of the femur 

 with the great trochanter (flg. 497). A second branch descends to anastomose with the ascend- 

 ing branch of the second perforating. 



The second perforating artery [a. perforans secunda] which is given off from the profunda as 

 it lies behind the adductor longus, pierces the adductor brevis, and then passes through a second 

 aponeurotic opening in the adductor magnus a httle below that for the first perforating artery, 

 and also close to the linea aspera. It supplies the hamstring muscles, sends a branch upward to 

 anastomose with the descending branch of the first perforating, and another downward to anas- 

 tomose in like manner with the ascending branch of the third perforating. 



The third perforating artery [a. perforans tertia] also arises from the profunda as it lies under 

 the adductor longus, usually about the level of the lower border of the adductor brevis. It turns 

 beneath this border, and then, like the first and second perforating, passes through an aponeu- 

 rotic opening in the adductor magnus close to the linea aspera. It also supplies the hamstring 

 muscles, and divides into two branches, which anastomose above with the second perforating, 

 and below with the termination of the profunda. 



Two nutrient arteries to the femur [aa. nutritise femoris superior et inferior] arise from the 

 perforating arteries. The superior generally arises from the first perforating, the inferior 

 usually from the third. 



(6) The muscular branches [rami musculares], of the femoral artery supply 

 the sartorius, the rectus, the vastus medialis, the vastus intermedius (crureus), 

 and the adductor muscles. 



(7) The genu suprema (or anastomotica magna) arises from the front and 

 medial side of the femoral just before the latter perforates the adductor magnus 

 muscle, and almost immediately divides into branches, (a) saphenous, (6) muscu- 

 lar, and (c) articular. These branches may sometimes come off separately from 

 the femoral. 



(a) The saphenous branch [a. saphena] pierces the aponeurotic covering of the adductor 

 canal, passes between the sartorius and gracilis muscles along with the saphenous nerve, and, 

 perforating the deep fascia, supphes the skin of the upper and medial side of the leg and anasto- 

 moses with the inferior medial articular branch of the popliteal and the other vessels forming the 

 plexus or rete at the medial side of the knee. In its course it gives twigs to the lower part of the 

 sartorius and gracilis muscles. 



(6) The muscular branches [rr. musculares] run downward in front of the adductor magnus 

 tendon, burrowing amongst the fibres of the vastus mediahs as far as the medial condyle. They 

 break up into numerous twigs which supply the lower ends of the vasti muscles and adductor 

 magnus. One branch runs laterally across the lower end of the femur to end in the vastus 

 lateralis. 



(c) The articular branches [rr. articulares] come off from the saphenous and muscular 

 branches and enter the arterial rete on the medial and lateral sides of the knee. They anas- 

 tamose with the medial and lateral superior articular branches of the popUteal and the ante- 

 rior tibial recurrent and, Hke other vessels of the rete, supply branches to the joint. 



THE POPLITEAL ARTERY 



The popliteal artery [a. poplitea] (fig. 498) runs through the popliteal space or 

 ham. It is a continuation of the femoral, and extends from the aponeurotic 

 opening in the adductor magnus at the junction of the middle with the lower 

 third of the thigh to the lower border of the popliteus muscle, where it terminates 

 by dividing into the anterior and posterior tibial arteries. This division is on a 

 level with the lower border of the tuberosity of the tibia. As the artery passes 

 through the opening in the adductor magnus, it is accompanied by the pophteal 

 vein, and at times by the branch of the obturator nerve to the knee-joint. The 

 vein throughout is behind the artery, at first lying a little lateral to it, but as the 

 vessels pass through the popliteal space the vein crosses obliquelj' over the artery, 



