DISSECTION OF THE VASCULAR SYSTEM. 55 



of the thigh and the gastrocnemius ; it represents the 

 posterior tibial. 



B. VEINS BELONGING TO THE SYSTEM OF 

 THE POST'CAVA. 



1. The Post-cava {inferior vena-cava). Follow its 

 course to the diaphragm. It receives no branches in 

 the thoracic cavity. 



2. The Hepatic Veins. Where the cava pierces the 

 diaphragm it receives two hepatic veins, one usually- 

 larger than the other. 



3. The Phrenic Veins empty into the cava at about 

 the same level as the hepatic veins. They bring back 

 blood from the diaphragm. 



4. The Renal Veins. Follow the post-cava along the 

 dorsal wall of the abdomen. At first it is partly im- 

 bedded in the liver ; just below the liver it receives the 

 two large renal veins coming directly from the kid- 

 neys. The left is slightly posterior to the right. 



5. The ^'^exm.z.Wc (ovarian) Veins, corresponding to 

 the spermatic artei'ies. The one on the left side empties 

 into the left renal vein, the one on the right side di- 

 rectly into the cava. 



6. The Iliac Veins. Below the renal the cava re- 

 ceives several veins from the muscles of the abdominal 

 wall, and finally divides into two large branches, the 

 common iliac veins. Each of these in turn divides 

 into an external and an internal iliac vein which bring 

 back blood from the regions suppHed by the arteries of 

 the same name. 



