INFERIOR VENA CAVA. 



341 



upwards along the brim of the pelvis, and terminates opposite the 

 sacro-iliac symphysis by uniting with the internal iliac, to form the 

 common iUac vein. Immediately above Poupart's ligament it 

 receives the epigastric and the circumflexa ilii veins ; it has no 

 valves. 



The Internal iliac vein is formed by vessels which correspond 

 with the branches of the internal iliac artery; it receives the return- 

 ing blood from the gluteal, ischiatic, internal pudic, and obturator 

 veins, externally to the pelvis ; and from the vesical and uterine 

 plexuses within the pelvis. The vein lies to the inner side of the 

 internal iliac artery, and terminates by uniting with the external 

 iliac vein, to form the common iliac. 



The Vesical and prostatic plexus is an important plexus of veins 

 which surrounds the neck and base of the bladder and prostate 

 gland, and receives its blood from the great dorsal vein of the penis, 

 and from the veins of the external organs of generation. It is 

 retained in connexion with the sides of the bladder by a reflection 

 of the pelvic fascia. 



The Uterine plexus is situated around the vagina, and upon the 

 sides of the uterus, between the two layers of the broad ligaments. 

 The veins forming the vesical and uterine plexus are very subject 

 to the production of phlebolitis. 



The Common iliac veins are formed by the union of the external 

 and internal iliac vein on each side of the pelvis. The right common 

 iliac, shorter than the left, ascends obliquely behind the correspond- 

 ing artery ; and upon the intervertebral substance between the fourth 

 and fifth lumbar vertebra?, unites with the vein of the opposite side, 

 to form the inferior cava. The left common iliac, longer and more 

 oblique than the right, ascends behind, and a little internally to* the 

 corresponding artery, and passes beneath the right common iliac 

 artery, near to its origin, to unite with the right vein in the formation 

 of the inferior vena cava. The right common iliac vein has no 

 branch opening into it; the left receives the vena sacra media. 

 These veins have no valves. 



INFERIOR VENA CAVA. 



The inferior vena cava is formed by the union of the two common 

 iliac veins, upon the intervertebral substance between the fourth 

 and fifth lumbar vertebra. It ascends along the front of the vertebral 

 column, on the right side of the abdominal aorta, and passing through 

 the fissure in the posterior border of the liver and the quadrilateral 

 opening in the tendinous centre of the diaphragm, terminates in the 

 inferior and posterior part of the right auricle. There are no valves 

 in this vein. 



It is in relation from below upwards, in front with the mesentery, 

 transverse duodenum, portal vein, pancreas, and liver which nearly 

 and sometimes completely surrounds it; behind it rests upon the 

 vertebral column and right crus of the diaphragm, from which it is 



