342 BRANCHES OF INFERIOR CAVA. 



separated by the right renal and lumbar arteries ; to the right it has 

 the peritoneum and sympathetic nerve ; and to the left the aorta. 



The Brandies which the inferior cava receives in its course, are 

 the 



Lumbar. 



Right spermatic, 



Renal, 



Supra-renal, 



Phrenic, 



Hepatic. 



The Lumbar veins, three or four in number on each side, collect 

 the venous blood from the muscles and integument of the loins, and 

 from the spinal veins ; the left are longer than the right from the 

 position of the vena cava. 



The Right spermatic vein is formed by the two veins which re- 

 turn the blood from the venous plexus, situated in the spermatic 

 cord. These veins follow the course of the spermatic artery, and 

 unite to form the single trunk which opens into the inferior vena 

 cava. The left spermatic vein terminates in the left renal vein. 



The Ovarian veins represent the spermatic veins of the male, and 

 collect the venous blood from the ovaries, round ligaments, and 

 Fallopian tubes, and communicate with the uterine sinuses. They 

 terminate as in the male. 



The Renal or emulgent veins return the blood from the kidneys ; 

 their branches are situated in front of the divisions of the renal 

 arteries, and the left opens into the vena cava somewhat higher than 

 the right. The left is longer than the right in consequence of the 

 position of the vena cava, and crosses the aorta immediately below 

 the origin of the superior mesenteric artery. It receives the left 

 spermatic vein, which terminates in it at right angles : hence the 

 more frequent occurrence of varicocele on the left than on the right 

 side. 



The Supra-renal veins terminate partly in the renal veins, and 

 partly in the inferior vena cava. 



The Phrenic veins return the blood from the ramifications of the 

 phrenic arteries ; they open into the inferior cava. 



The Hepatic veins form two principal trunks and numerous smaller 

 veins which open into the inferior cava, while that vessel is situated 

 in the posterior border of the liver. The hepatic veins commence 

 in the liver by minute venules, the intralobular veins in the centre of 

 each lobule; these pour their blood into larger vessels, the sublobular 

 veins ; and the sublobular veins constitute by their convergence and 

 union, the hepatic trunks, which terminate in the inferior vena cava. 



AZYGOS VEINS. 



The azygos veins form a system of communication between the 

 superior and inferior vena cava, and serve to return the blood from 



