PLATE LXVIII. 



THE FOURTH VIEW OF THE ABDOMINAL VISCERA- 

 PORTAL VEIN, PANCREAS AND SPLEEN, &c. 



In this dissection tho stomach, duodenum, and transverse colon were removed, and 

 the liver stitched to the anterior wall to display the contents of the lesser omentum 

 viz. the common bile-duct, formed by the junction of the hepatic and cystic ducts, lying 

 in front and to tho right, the hepatic artery to the left and on a plane slightly posterior, 

 the portal vein being seen behind and between the other two. The spleen has been left 

 resting on the costo-colic ligament, a process of peritoneum which extends from the 

 splenic flexure of the colon to the tenth and eleventh ribs. 



The portal vein is about three inches long, and usually commences at the upper 

 border of the pancreas by the junction of the superior mesenteric and splenic veins. In 

 66 per cent, of cases the inferior mesenteric joins the splenic, and in 88 per cent, it joins 

 the superior mesenteric, while in the remaining 1 per cent, it runs into the junction of 

 the two veins. The ending of the inferior mesenteric vein in the splenic appears to be 

 a feature in the higher development of animals, as in all mammalia below monkeys it 

 opens into the superior (Treves). The portal system has no valves, and communicates 

 with the systemic venous system at 



1. The rectum (superior with middle and inferior haemorrhoidal). 



2. The cssophagus (gastric with the cesophageal). 



8. Small veins of duodenum and pancreas with the left renal. 



4. The superficial portal capillaries and the capillaries in the falciform ligament of 



the liver with the phrenic veins. 



5. Along the round ligament there are often one or more small veins which form a 



communication with the epigastric veins, and in certain diseased states of the 

 liver are often much dilated.- They are called the parumbilical veins, ' and 

 may represent the anterior abdominal vein or suprahepatic 'termination of the 

 hypoblastic vein ' (Macalister). 



