ABDOMINAL CAVITY 371 



of the lower surface of the right lobe through which the 

 vessels and ducts enter and leave the liver. It lies near the 

 posterior border of the lower surface, between the lower 

 end of the caudate lobe posteriorly and the quadrate lobe 

 anteriorly. It extends, transversely, from the upper and 

 posterior end of the fossa for the gall-bladder, on the right, 

 to the upper and posterior end of the fossa for the umbilical 

 vein, on the left. 



In the upper part of the lesser omentum, immediately 

 below the porta, the bile-duct, the hepatic artery, and the 

 portal vein are in close relation to each other, the artery 

 lying to the left, the duct to the right, and the portal vein 

 behind and between them. The branches of the three 

 structures enter the porta in the same relative positions, and, 

 as they pass into it, they become enclosed in a sheath of the 

 fibrous capsule of the liver (O.T. Glisson's capsule). Trace 

 them for a short distance into the substance of the liver and 

 note that the portal vein branches like an artery, and wherever 

 it divides, there also will the hepatic artery and hepatic duct 

 be found to divide. The branches of the three structures, 

 therefore, traverse the liver substance in company, and the 

 fibrous capsule is prolonged into the liver with them, and 

 follows them in their ramifications. The student is now in 

 a position to understand the meaning of the term "portal 

 canal" It is employed to denote a channel in the liver 

 substance, lined by a prolongation of the fibrous capsule, 

 and holding in its interior a branch of the portal vein, a 

 branch of the hepatic artery, and a branch of the hepatic duct. 



Vessels of the Liver. Blood enters the liver (i) by the 

 hepatic artery -, (2) by the portal vein ; whilst it passes away from 

 the liver by the hepatic veins. 



The hepatic artery is a branch of the cceliac artery. It 

 carries arterial blood for the nourishment of the liver sub- 

 stance and divides into two branches which enter the liver 

 at the extremities of the porta hepatis (p. 300). 



The portal vein carries venous blood which it has gathered 

 from the spleen, pancreas, and gall-bladder, and from the 

 entire length of the abdominal portion of the alimentary 

 canal (with the exception of the anal canal of the rectum). 

 It reaches the inferior surface of the liver at the right extremity 

 of the porta hepatis, where it divides into its two terminal 

 branches. The terminal part of the portal vein, just before 

 n 24 a 



