542 



THE POETAL VEIN. 



duodenum and then between the layers of the small omentum, to the transverse 

 fissure of the liver. In the omentum it is placed close behind the hepatic artery on 

 the left and the bile duct on the right, and is accompanied by filaments of the hepatic 

 plexus of nerves, as well as by numerous lymphatics, all these being surrounded by 

 the loose connective tissue constituting the capsule of Glisson. 



Near the right end of the. transverse fissure, the vena portse becomes somewhat 

 enlarged (sinus of the portal vein), and immediately divides into two branches. That 



Fig. 416. DIAGRAMMATIC SKETCH OP 



THE PORTAL VEIN AND ITS TRIBU- 

 TARIES. (Allen Thomson.) 



The liver is turned upwards, so as 

 to present a portion of its under surface : 

 a, gall-bladder ; b, quadrate lobe ; c, left 

 lobe ; 1,1, portal vein ; 2, 2, superior 

 mesenteric vein ; 2', its middle colic 

 branch, forming loops with the right and 

 left colic veins ; 3, 3, intestinal branches ; 

 + , pancreatico-duodenal branch ; 4, right 

 colic branch ; 5, ileo-colic ; tf, 6, coronary 

 vein of stomach ; + +, right gastro- 

 epiploic ; 7, splenic vein ; 7', its branches 

 from the spleen ; 7", its branches from 

 the stomach ; 8, inferior mesenteric vein ; 

 9, left colic branch ; 9', its communica- 

 tion with the middle colic ; 10, sigmoid ; 

 11, superior hsemorrhoidal ; 12, right, 

 and 13, left division of portal vein in 

 the transverse fissure of the liver ; 14, 14, 

 obliterated cord of umbilical vein (round 

 ligament of liver) ; 15, obliterated cord 

 of ductus venosus ; 16, part of inferior 

 vena cava. 



of the right side enters directly 

 the substance of the correspond- 

 ing lobe of the liver, and spreads 

 out into branches, each of which 

 is accompanied by an offset of the 

 hepatic artery and of the hepatic 

 duct. The left branch, which is 

 smaller but necessarily longer, 

 passes across to gain the left end 

 of the tranverse fissure, where it 

 ramifies like the preceding branch. 

 Opposite the fore part of the 

 longitudinal fissure, the left 

 branch of the portal vein is joined anteriorly by the so-called round ligament of the 

 liver, the remains of the umbilical vein of the foetus ; and a little to the right of 

 this, from its posterior aspect, another fibrous cord, the obliterated ductus venosus, 

 passes backwards to join the inferior vena cava. 



Tributaries The principal branches which by their union contribute to form 

 the portal vein are the superior and inferior mesenteric, and the splenic veins. It 

 is also joined by the pyloric and coronary veins from the stomach, and sometimes by 

 the cystic vein from the gall-bladder ; but the latter vessel more frequently enters 

 its right branch. 



The superior mesenteric vein lies to the right side and somewhat in front of 

 the artery of the same name. The distribution of its branches corresponds with that 

 of the superior mesenteric artery, and it returns the blood from the several parts 



