490 



PROF. G. S. THAPAR ON THE 



The hepatic portal veAn (h.p.v.) forms two complete loops in the 

 mesentery of the small intestine (text-lig. 2) ; in the course of the 

 second loop it receives splenic, pancreatic, and gastric veins. It 

 runs forwards to the hinder end of the median sulcus of the liver, 

 and after receiving the anterior abdominal vein divides into two 

 branches, one entering each lobe of the liver towards its dorsal 

 side. 



Text-fieure 2. 



The Hepatic Portal Vein and its connections. 

 Art., anterior abdominal vein; c, caudal; ep.v., epigastric; f., femoral; 

 ^1-/4, veins from the fat-body; Ji., hypogastric; h.p.v., hepatic portal vein ; 

 p., pelvic; sc, sciatic; r., ischiomesenteric ; i, 2, 3, 4, 5, veins forming 

 the hepatic portal; 6, gastric; x., connection between hypogastric and 

 ischiomesenteric veins. 



It would thus appear that all the blood from the limbs and 

 alimentary canal passes through the liver before entering the 

 postexuor vena cava. A large part of the blood from the hinder 

 region passes along the ischio- mesenteric vein into the liver, while 

 a small part enters the kidneys by way of the hypogastric veins. 

 Thus while the hepatic portal system is increasing in complexity 

 the renal portal is reduced. The short connection between the 

 hypogastric and ischio-mesenteric veins would allow the blood to 

 flow from the ischio-mesenteric to the hypogastric or vice versa ; 

 but the possibility of a flow into the hypogastric is perhaps 

 diminished by reason of the direction of the connectinof vessel, 



