PORTAL VEIN. 



153 



VENA AZYGOS. 



This vein*'' commences in the lumbar regions, and being joined by 

 the intercostal veins of the right side, winds around the root of the 

 right lung and empties into the descending cava. It also receives 

 the right bronchial and the left superior intercostal veins. 



Ve7ia heniiazygos^^ — This is formed by the lower intercostal and 

 superior lumbar veins, and passes in front of the vertebral column 

 to join the vena azygos. 



Left superior intercostal?^ — This receives the blood from the sixth 

 superior intercostal and left bronchial veins, and forms a communi- 

 cation between the left subclavian and azygos veins. 



The above veins form a communication between the venous blood 

 of the upper and lower extremity, independent of its mingling in the 

 heart. (Fig. 134.) 



PORTAL VEIN. 



Fig. 135. 



^ \ 



This vein collects 

 the blood from all 

 the chylopoietic vis- 

 cera, ^ and entering 

 the transverse fissure 

 of the liver, divides 

 into the right and 

 left sinuses. In its 

 course it receives the 

 inferior* and su- 

 perior^ mesenteric 

 veins, splenic,^ and 

 gastric;^ and then is 

 included with the 

 hepatic artery, *° and 

 the ductus communis 

 choledochus in the 

 capsule of Glisson. 



Vesical 'plexus. — 

 This plexus sur- 

 rounds the neck of 

 the bladder, semi- 

 nal vesicles, prostate 

 gland, and penis ; its 

 blood passes into the 

 internal iliac vein. 



JJterine -plexus. — Surrounds the uterus and vagina and empties as 

 the vesical does. 



HcBmorrhoidal veins. — Surround the rectum and empty into the 

 inferior mesenteric. 



