Portal Hypertension in Children

The portal vein is formed by the confluence of the splenic vein with the superior mesenteric vein and its formation mostly occurs behind the pancreas in the retroperitoneum. It transports the blood mainly from the gastro-intestinal tract and the spleen to the liver. Seventy percent of the total blood supply to the liver is contributed by the portal vein while the hepatic artery contributes to the remaining thirty percent. The portal venous system is the only venous system in our body, which begins with capillaries and ends with capillaries. The intrahepatic branches of the portal vein terminate in small vessels that supply the hepatic sinusoids. Embryologically, the systemic veins of our body develop from the intraembryonic anterior and posterior cardinal veins while the portal system develops from the extra-embryonic vitelline and umbilical veins, which drain from the yolk sac and the placenta.