94 VENA PORTARUM. HEPATIC DUCT. 



of the colon, becomes finally a large vessel, and commonly 

 unites with the splenic about an inch and a half before its 

 junction with the superior mesenteric vein. The vena porta- 

 rum, thus formed, proceeds towards the liver, inclining to the 

 right, and is generally about three inches in length : in 

 its course it sometimes receives small veins, which in other cases 

 pass to its splenic and mesenteric branches. When it has 

 arrived at the great transverse sinus of the liver, it divides into 

 two large branches, each of which forms nearly a right angle 

 with it. Their size is so great, that, when distended with 

 injection, they appear like an independent vessel, into which 

 the vena portarum enters ; and on this account they are called 

 the Great Sinus of the vena portarum. They do not adhere 

 firmly to the glandular substance of the liver, but are united to 

 it by cellular membrane. The right branch is the widest and 

 shortest. It generally divides into three branches ; an anterior, 

 a posterior, and a lateral branch ; which ramify minutely, and 

 extend themselves in the right lobe. The left branch is much 

 longer, and continues to the extent of the transverse fissure. 

 Near its termination it is joined by the umbilical ligament, 

 which has been already mentioned. This branch is generally 

 in contact with a branch of the hepatic artery, and of the hepa- 

 tic duct; and ramifies like the right branch, into the contiguous 

 parts of the liver. 



The Hepatic or excretory duct originates, by very small 

 vessels, from the acini or corpuscles of which the liver is com- 

 posed, and into which the minute ramifications of the vena 

 portarum and hepatic artery extend. They accompany these 

 vessels, increasing as they increase, although the fluid they 

 contain moves in an opposite direction ; and two Targe branches 

 which they ultimately form are situated at the portae of the 

 liver, in contact with the great branches of the vena portarum 

 and the hepatic artery. 



These three vessels are in contact with each other before 

 they enter the liver. The biliary duct is anterior, the vena 

 portarum posterior, and the artery to the left of them. They 

 are accompanied by nerves and lymphatic vessels, and are 



