The development of surgical procedures which can modify the course of disease associated with portal hypertension has made early recognition and accurate diagnosis of this condition imperative. This applies in particular to the pediatric age group. In many cases found in infants and children such complications as hemorrhage from esophageal varices and pathological depression of erythrocyte, leucocyte, and platelet levels due to hypersplenism can be avoided by appropriate treatment. Accurate diagnosis of the cause of portal hypertension including the site of portal obstruction is necessary not only to define clearly the indications for surgery, but also to plan the most appropriate procedure.Several extensive anatomical investigations of the portal venous system have been made recently because of the renewed interest in portal decompression in the treatment of portal hypertension.1 A compilation of the most frequently encountered patterns in the disssections of 92 specimens by Douglass, Baggenstoss, and Hollinshead 2 of the proximal terminations of all the major veins of the extrahepatic portal system is shown in Figure 1. The pancreas is represented by the shaded area. The splenic and superior mesenteric veins join to form the portal vein just pos¬ terior to the head of the pancreas. A variable number of splenic trunks converge near the hilus to form the splenic vein. The left gastroepiploic and numerous small pancreatic branches join the splenic vein, as does usually the inferior mesenteric, which is formed by the superior hemorrhoidal and left colic veins. The chief tributaries of the superior mesen¬ teric vein are the intestinal, middle colic, ileocolic, right colic, omental, right gastroepiploic, and inferior pancreaticoduodenal veins. The coronary, or left gastric, vein usually termi¬ nates at the junction of the superior mesen¬ teric and splenic veins. The superior pan¬ creaticoduodenal; pyloric, or right gastric; cystic, and in 30% of the cases the accessory pancreatic vein enter the thick-walled portal vein. Figure 2 shows Gilfillan's 3 statistical anal¬ ysis of the morphologic variations in the portal vein and its tributaries, derived from 61 postmortem dissections. The coronary, or left gastric, vein and its accompanying pyloric vein originated from the portal vein in 68%, from the junction of the splenic and superior mesenteric veins in 8%, and from the splenic vein in 24% of cases. He found the inferior mesenteric vein entered the splenic vein in 55.6% of the cases, the junction of superior mesenteric and splenic veins in 14%, and in 29.6% of the cases drained into the superior mesenteric vein.The first use of the term "portal hyper¬ tension" was by Gilbert,4 in 1899. Not until
