POPLITEAL FEMORAL ILIAC. 



653 



Fig. 312. External or 

 Short Saphenous Vein. 



The valves in the deep veins are very numerous. 



The Popliteal Vein is formed by the junction of the venae comites of the ante- 

 rior and posterior tibial vessels ; it ascends through the popliteal space to the 

 tendinous aperture in the Adductor Magnus, where it 

 becomes the femoral vein. In the lower part of its 

 course, it is placed internal to the artery ; between the 

 heads of the Gastrocnemius, it is superficial to that 

 vessel ; but above the knee-joint, it is close to its outer 

 side. It receives the sural veins from the Gastroc- 

 nemius muscle, the articular veins, and the external 

 saphenous. The valves in this vein are usually four 

 in number. 



The Femoral Vein accompanies the femoral artery 

 through the upper two-thirds of the thigh. In the 

 lower part of its course, it lies external to the artery ; 

 higher up, it is behind it ; and beneath Poupart's liga- 

 ment, it lies to its inner side, and on the same plane. 

 It receives numerous muscular branches ; the pro- 

 funda femoris joins it about an inch and a half below 

 Poupart's ligament, and near its termination the in- 

 ternal saphenous vein. The valves in this vein are 

 four or five in number. 



The External Iliac Vein commences at the termi- 

 nation of the femoral, beneath the crural arch, and 

 passing upwards along the brim of the pelvis, termi- 

 nates opposite the sacro-iliac syrnphysis, by uniting 

 with the internal iliac to form the common iliac vein. 

 On the right side, it lies at first along the inner side 

 of the external iliac artery; but as it passes upwards, 

 gradually inclines behind it. On the left side, it lies 

 altogether on the inner side of the artery. It receives, 

 immediately above Poupart's ligament, the epigastric 

 and circumflex iliac veins. It has no valves. 



The Internal Iliac Vein is formed by the vena3 comites 

 of the branches of the internal iliac artery, the umbili- 

 cal arteries excepted. It receives the blood from the 

 exterior of the pelvis by the gluteal, sciatic, internal 

 pudic, and obturator veins ; and from the organs in 

 the cavity of the pelvis by the haemorrhoidal and 

 vesico-prostatic plexuses in the male, and the uterine 

 and vaginal plexuses in the female. The vessels forming these plexuses are 

 remarkable for their large size, their frequent anastomoses, and the number of 

 valves which they contain. The internal iliac vein lies at first on the inner 

 side and then behind the internal iliac artery, and terminates opposite the sacro- 

 iliac articulation, by uniting with the external iliac, to form the common iliac 

 vein. This vessel has no valves. 



The hdemorrhoidal plexus surrounds the lower end of the rectum, being formed 

 by the superior hasmorrhoidal veins (branches of the inferior mesenteric),and 

 the middle and inferior hsemorrhoidal, which terminate .in the internal iliac. 

 The portal and general venous systems have a free communication by means of 

 the branches composing this plexus. 



The vesico-prostatic plexus surrounds the neck and base of the bladder and 

 prostate gland. It communicates with the hternorrhoidal plexus behind, and 

 receives the dorsal vein of the penis, which enters the pelvis beneath the sub> 

 pubic ligament. This plexus is supported upon the sides of the bladder by a 

 reflection of the pelvic fascia. The veins composing it are very liable to be- 

 come varicose, and often contain hard earthy concretions, called pfilebolithes. 



