THE PORTAL SYSTEM OF VEINS 757 



of the stomach; it runs from right to left along the lesser curvature of the stomach, 

 between the two layers of the gastrohepatic omentum, to the cesophageal end 

 of the stomach, where it receives some cesop'iageal veins. It then turns backward 

 and passes from left to right behind the lesser sac of the peritoneum and ends 

 in the portal vein. 



The pyloric vein (v. pylorica) is of small size, and runs from left to right along 

 the pyloric portion of the lesser curvature of the stomach, between the two layers 

 of the gastrohepatic omentum, to terminate in the portal vein. 



The cystic vein (v. cystica) (Fig. 529) drains the blood from the gall-bladder, 

 and, ascending along the cystic duct, usually terminates in the right branch of the 

 portal vein. 



Pammbilical Veins (ri\ parumbilicales). In the course of the ligamentum 

 teres of the liver and of the urachus small veins (parumbilical) are found, which 

 establish an anastomosis between the veins of the anterior abdominal wall and 

 the portal and iliac veins. The best marked of these small veins is one which 

 commences at the umbilicus and runs backward and upward in, or on the surface 

 of, the ligamentum teres between the layers of the falciform ligament to terminate 

 in the left branch of the portal vein. 



Anastomoses between the Portal and Systemic Veins. Some tributaries of 

 the portal vein communicate with certain neighboring systemic veins. The more 

 important communications are between (a) the gastric veins and the o?sophageal 

 veins which empty into the vena azygos minor; (6) the parumbilical veins, which 

 anastomose with the deep epigastric and internal mammary veins; (c) the superior 

 and middle hemorrhoidal veins, the latter opening into the internal iliacs. 



Applied Anatomy. Obstruction to the portal vein may produce ascites, and thi may 

 arise from many causes, as n ^ the pressure of a tumor on the portal vein, such as cancer or 

 hydatid cyst, in the liver, enlarged lymph nodes in the lesser omentum. or cancer of the 

 head of the pancreas: (2) from cirrhosis of the liver, when the radicles of the portal vein are 

 pressed upon by the contracting fibrous tissue in the portal canals; (3) from valvular disease 

 of the heart, and back pressure on the hepatic veins, and so on the whole of the circulation 

 through the liver. In this condition the prognosis as regards life and freedom from ascites 

 may be much improved by the establishment of a ^ood collateral venous circulation to relieve 

 the portal obstruction in the liver. This is effected by communications between (a) the gastric 

 veins, and the oesophageal veins emptying themselves into the vena azygos minor inferior, which 

 often project as a varicose bunch into the stomach; (6) the veins of the colon and duodenum, 

 and the left renal vein; (c) the accessory portal system of Sappey, branches of which pass in 

 the round and falciform ligaments (particularly the latter), to unite .with the epigastric and 

 internal mammary veins, and through the diaphragmatic veins with the azygos; a single large vein 

 shown to be a parumbilical vein, may pass from the hilus of the liver by the round ligament to 

 the umbilicus, producing there a bunch of prominent varicose veins known as the Caput Medusae; 

 (d) the veins ,of Retzius, which connect the intestinal veins with the inferior vena cava and its 

 retroperitoneal branches; (e) the inferior mesenteric veins, and the hemorrhoidal veins that 

 open into the internal iliacs; (/) very rarely the ductus venosus remains patent, affording a 

 direct connection between the portal vein and the inferior vena cava. 



An operation for the relief of portal obstruction on these lines has been advocated by Ruther- 

 ford Morison and by Talma. It consists in curetting the opposed surfaces of the liver and 

 diaphragm and stitching them together, so as to secure vascular inflammatory adhesions between 

 the two. The great omentum may with advantage be interposed between them, so as to increase 

 the amount of the adhesions, and the spleen has been similarly scraped and sutured to or into 

 the abdominal wall. The operation should not be deferred until the patient is moribund. 



Thrombosis of the portal vein, or pylethrombosis, is a very serious event, and is oftenest due 

 to pathological processes causing compression of the vessel or injury to its wall, such as tumors 

 or inflammation about the pylorus, head of the pancreas, or appendix, or to gallstones or cir- 

 rhosis of the liver. If the thrombus is infected with bacteria, as is often the case when it is due 

 to appendicitis, septic or suppurative pylephlebitis results; this condition is known also as 

 portal pyemia. Fragments of the infected clot break off and are carried away to lodge in the 

 smaller veins in the liver, with the development of multiple abscesses in its substance and a 

 rapidly fatal result. When the thrombus is sterile, the chief signs produced are enlargement 

 of the spleen, recurrent ascites, and the establishment of a collateral venous circulation, the 

 case clinically resembling one of atrophic cirrhosis of the liver, jy 



