DISSECTING MANUAL. 



Portal System. The veins involved are single; the tribu- 

 taries of origin agree closely with the terminal arterial branches 

 and have similar names. The terminal veins, however, leave 

 their arteries finally; the inferior mesenteric vein joins the 

 splenic and the latter unites with the superior mesenteric to 

 form the portal vein. [901] 



Portal Vein. Commencing by the union of the splenic and 

 superior mesenteric, behind and to the left of the neck of the 

 pancreas, this ascends behind the duodenum to the foramen 

 of Winslow and runs forward in the right pancreatico-gastric 

 fold to the gastro-hepatic omentum ; then ascending in front of 

 the foramen of Winslow, behind the bile duct and hepatic 

 artery, to the transverse fissure of the liver, it divides into two 

 branches, right and left, for those lobes. The left branch also 

 supplies branches to the quadrate and Spigelian lobes; the 

 round ligament joins it in front, while from its back a fibrous 

 cord (ductus arteriosus) runs to the inferior vena cava. The 

 coronary and pyloric veins join the portal vein; the cystic 

 vein joins its right branch. [902] 



The superior mesenteric begins in the right iliac fossa and 

 ascends on the right of its artery, receiving corresponding 

 branches. The splenic begins at the hilus of the spleen and 

 runs just below its artery and then across the aorta; besides 

 branches corresponding to those of the artery it receives the 

 inferior mesenteric. The inferior mesenteric begins as the su- 

 perior hemorrhoidal, which drains the hemorrhoidal plexus 

 surrounding the rectum. It ascends with its artery, receiving 

 the sigmoid and left colic; then crossing over the left renal 

 vein it runs behind the pancreas and joins the splenic. [903] 



LYMPHATICS. 



The thoracic duct begins as an elongated ovoid dilatation, 

 (receptaculum chyli) which is two or three inches long and lies 

 in front of the two upper lumbar vertebra, between the aorta 



[214] 



