672 THE VEINS 



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 Gastro- 

 cnemius 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 at Poupart's ligament it lies to its inner side and 

 on the same plane. It receives numerous muscular tributaries : the profunda 

 femoris and deep external pudic veins join it near Poupart's ligament and about 

 an inch and a half below the internal saphenous vein. The valves in this vein are 

 four or five in number. 



The External Iliac Vein commences at the termination of the femoral, beneath 

 the crural arch, and, passing upward along the brim of the pelvis, terminates 

 opposite the sacro-iliac synchondrosis 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 upward 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 deep epigastric and deep circumflex 

 iliac veins and a small pubic vein, corresponding to the pubic branch of the 

 obturator artery. According to Friedreich, it frequently contains one, and some- 

 times two valves. 



The Deep Epigastric Veins. Two veins accompany the deep epigastric artery ; 

 they usually unite into a single trunk before their termination in the external 

 iliac vein. 



The Deep Circumflex Iliac Veins. Two veins accompany the deep circumflex 

 iliac artery. These unite into a single trunk which crosses the external iliac 

 artery just above Poupart's ligament and terminates in the external iliac 

 vein. 



The Internal Iliac Vein is formed by the venae comites of the branches of the 

 internal iliac artery, the umbilical 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 inter- 

 nal 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 internal pudic veins (venaz comites) have the same course as the 

 internal pudic artery. They receive tributaries corresponding to the branches 

 of the artery, except the tributary corresponding to the dorsal artery of the 

 penis ; that is, the dorsal vein of the penis, which opens into the prostatic 

 plexus. 



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

 by the superior hsemorrhoidal veins (tributaries of the inferior mesenteric), and 

 the middle and inferior hgemorrhoidal, which terminate in the internal iliac. The 

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

 branches composing this plexus. 



Surgical Anatomy. The veins of this plexus are apt to become dilated and varicose and 

 form piles. This is partly due to the free communication between the portal and systemic circu- 

 lation which here exists, so that any obstruction to the flow of blood through either the inferior 

 vena cava or its main tributaries, or through the portal vein, tends to produce passive congestion 

 of this plexus. The condition is also partly due to the fact that the vessels are contained in 

 very loose, lax connective tissue, so that they get less support from surrounding structures 

 than most other veins, and are less capable of resisting increased blood-pressure. And, 

 finally, the condition is favored by gravitation, inasmuch as the portal vein contains no 

 valves. 



