THE LOWER EXTREMITY, POSTERIOR. 623 



The Popliteal Vein. Fig. 128. 



The popliteal vein is formed by the junction of the venae 

 comites of the anterior and posterior tibial arteries, at the 

 lower border of the popliteus muscle, and passing upward 

 becomes the femoral vein at the opening in the adductor 

 magnus muscle. Its relation to the popliteal artery. It 

 lies behind the artery and crosses it slightly obliquely from 

 below upward, and from the inner to the outer side. 



The Popliteal Artery. Figs. 128, 129, 130. 



The popliteal artery is a continuation of the femoral from 

 the opening in the adductor magnus muscle to the lower 

 border of the popliteus muscle, where it terminates by 

 dividing into the anterior and posterior tibial arteries 

 opposite the lower margin of the tibial tubercle. The course 

 of the artery is indicated by a line drawn vertically through 

 the popliteal space. 



Relations. The artery rests upon the floor of the popliteal 

 space, which is formed by the posterior surface of the lower 

 end of the femur, the posterior ligament of the knee joint, 

 the posterior margin of the tibia (covered by the posterior 

 ligament), and the popliteus muscle, from which it is 

 separated by the fascia covering the muscle. 



The popliteal vein lies close behind the artery, being a 

 little external to it above, and slightly internal to it below. 



The internal popliteal nerve is behind (or superficial to) 

 both artery and vein, and crosses them about the middle of 

 the space, from the outer to the inner side (above down- 

 ward). 



The semimembranosus muscle covers the upper part of 

 the artery (vein and nerve), the inner head of the gastroc- 

 nemius, the lower part of it, the fascia (two layers) and 

 integument for its entire course. 



