POPLITEAL ARTERY AND BRANCHES. 127 



the heads of the gastrocnemins, and is covered only by the fascia lata 

 and the integuments. Beneath it is the femur, with the posterior 

 ligament of the knee-joint. 



In contact with the vessel, and somewhat on the outer side at position of 

 first, lies the popliteal vein, so that on looking into the space, the 

 arterial trunk is almost covered ; but in the interval between the 

 heads of the gastrocnemius, the vein and its branches altogether 

 conceal the artery. In the lower part of the ham the short saphen- 

 ous vein (fig. 53, ?, p. 131) and the muscular branches of the artery 

 are also superficial to the popliteal trunk. 



More superficial than the large vessels, and slightly external to and of the 

 them in position, is placed the internal popliteal nerve, which, with n 

 its branches, lies over the artery, like the vein, between the heads 

 of the gastrocnemius. In the bottom of the hollow the small 

 obturator nerve runs on the artery to the joint. 



Dissection. To see the deep part of the artery, the inner head Cut inner 

 of the gastrocnemius should be cut through and raised. On reniov- g2trocne- 6 

 ing the areolar tissue the vessels and nerves will appear. The mius - 

 lower articular branches of the vessels and nerve are now brought 

 into view ; the inner artery is below the head of the tibia, and 

 the outer, higher up, between the femur and the fibula, each with 

 a vein ; and a companion nerve. 



Beyond the ham. While the artery is beneath the gastrocnemius Artery be- 

 sinks deeply into the limb ; here it is crossed by a small muscle yc 

 the plantaris (c), and the ending is concealed by the soleus (B). 

 It rests on the popliteus muscle. 



Both the companion vein and the internal popliteal nerve change position of 

 their position to the artery, and gradually cross over it, so as to nerve* 

 lie on its inner side at the lower border of the popliteus. 



Sometimes the artery bifurcates as high as the back of the knee-joint ; and High 

 then the anterior tibial artery may lie beneath the popliteus muscle. division. 



BRANCHES (figs. 52 and 53) are furnished by the artery to the Branches of 

 surrounding muscles, to the integuments, and to the articulation ; arter y- 

 those that belong to the joint are five in number, and are called 

 articular, viz., two superior, inner and outer ; two inferior, also 

 inner and outer ; and a central or azygos branch. 



1. The muscular branches are upper and lower. The upper set, Muscular 

 three or four in number, arise above the knee, and end in the semi- r es> 

 membranosus and biceps muscles, communicating with the per- 

 forating and muscular branches of the profunda. The lower set 

 (sural) are furnished to the muscles of the calf, viz., gastrocnemius, 

 soleus, and plantaris. 



2. The cutaneous or superficial sural branches descend to the skin and cuta- 

 of the calf of the leg : they are usually three in number, one in the ne 

 middle line, and one over each head of the gastrocnemius. 



3. The superior articular arteries arise from the popliteal trunk, Articular 

 one from the inner and one from the outer side, above the condyles a^fivef 

 of the femur ; they are directed almost transversely beneath the Two 

 hamstring muscles, and turn round the bone to the front of the joint, superior : 



