THE PORTAL SYSTEM 295 



THE PORTAL SYSTEM 



The portal system consists of the veins which drain the gall- 

 bladder, stomach, spleen, pancreas, duodenum, jejenum, ileum, 

 cecum, colon, and upper portion of the rectum; these tributaries 

 usually bear the same names as the arteries, which they accom- 

 pany. However, the portal vein is found, directly, by the 

 splenic and superior mesenteric veins joining behind the neck 

 of the pancreas, also the gastric, pyloric, cystic, and parum- 

 bilical veins open into it before reaching the transverse fissure 

 of the liver. 



The portal vein, 3 inches long, ascends behind the duodenum 

 and between the layers of the lesser omentum. Here it runs 

 behind the hepatic artery and bile duct. Accompanied by the 

 hepatic plexus of nerves and lymphatics, all enclosed in Glisson's 

 capsule, it then enters the transverse fissure, forming near 

 the right end the "sinus," and divides into: A right branch, 

 to the right lobe, which distributes branches entering the 

 hepatic substance with the hepatic arterial branches and ducts; 

 and a left branch distributed like the right. 



The superior mesenteric, corresponding to the artery of the 

 same name, receiving also the right gastroepiploic vein, besides 

 branches accompanying those of the artery. It joins the 

 splenic vein. 



The splenic arises by five or six vessels uniting after leaving 

 the hilum, and runs to the right below the artery, joining the 

 above at a right angle to form the vena portse. It receives 

 the vasa brevia, left gastroepiploic, and pancreatic branches, and 

 the inferior mesenteric vein. 



The inferior mesenteric vein corresponds in branches and 

 course to the artery, and empties into the angle of junction 

 of the two preceding. 



The gastric vein accompanies the gastric artery and runs 

 along the lesser curvature of the stomach between the two 

 layers of the gastrohepatic omentum, it receives some esopha- 

 geal veins near the esophageal end of the stomach and then 

 runs from left to right posterior to the lesser peritoneal cavity 

 to open into the portal vein. 



The pyloric runs with the pyloric branch of the hepatic 

 artery, and joins the vena portse. 



