920 



HUMAN ANATOMY. 



lobe of the liver and to the greater part of the SpigeHan and quadrate lobes, the 

 remainder of these lobes and the left lobe receiving branches from the left trunk. 



The trunks of the vein or their branches enter the substance of the liver and 

 divide in a more or less distinctly dichotomous manner to form ijiterlobular veins^ 

 which, as their name indicates, occupy a position between the lobules of the organ, 

 and gix^e of^ capillaries which traverse the lobule and empty into the intralobular 

 veins, the origins of the hepatic veins. 



The portal vein measures about 8 cm. (3^ in.) in length and has a diameter of 

 from 1.5 to 2 cm. Its walls, especially in its upper portion, contain a considerable 

 quantity of muscle-tissue and it is destitute of valves. 



Relations, — At its origin the portal vein lies behind the head of the pancreas 

 and to the left of the vena cava inferior. As it ascends it comes to lie at first behind 



Fig. 772. 



Liver 



Kound lieaiiient of liver 



Hepatic duct 

 Cystic duct 



Gall-bladder, 



Cystic vein. 

 Portal vein. 



Common bile-duct 



Pyloric vein 

 Superior mesenteric vein 



Right 



gastro-epiploic veil 



Tributaries of 



middle colic vein 



Spigelian lobe of liver 

 Inferior vena cava 



Right crus of diaphragm 



Hepatic artery 



Spleen 



Gastric artery 

 Coeliac axis 

 Stomach 

 Splenic artery 

 Gastric vein 



Splenic vein 



Inferior mesenteric vein 

 Left gastro-epiploic vein 

 Pancreas 



Portal vein and its tributaries ; liver has been pulled upward. 



the first portion of the duodenum and then between the two layers of the lesser 

 omentum. In this latter portion of its course it is associated with the hepatic artery 

 and the common bile-duct, both of which lie anterior to it, the artery to the left and the 

 duct to the right. It enters the transverse fissure towards its right extremity, hence 

 the shortness of the right trunk compared with the left, and its trunks have in front 

 of them the branches of the hepatic artery, the hepatic ducts lying anterior to these. 

 Tributaries. — The tributaries of the portal vein are : (i) the superior mese?i- 

 teric, (2) the splenic, (3) the inferior mesenteric, (4) the gastric, (5) \.\\e pyloric, 

 and (6) the cystic veins. In addition to these principal tributaries, the portal vein, or 

 its branches within the liver, also receives a number of small veins which have their 

 origin in the falciform ligament of the liver and in the lesser omentum, and, further- 

 more, it receives at the transverse fissure (7) ^om^ par umbilical veins which ascend 

 the anterior abdominal wall along with the round ligament. 



