Portal Vein is a large venous trunk draining the blood from the stomach and intestine and contains the digested nutrients, which are absorbed from the small intestine and destined to reach the liver. It is formed by the union of two trunks, gastric and mesenteric.
The gastric trunk is formed by the union of the right ruminal, splenic, left ruminal, reticular and omaso-abomasal veins.
It also receives the gastro-duodenal and pancreatic veins. The mesenteric trunk is formed by the union of anterior and posterior mesenteric veins.
The portal vein thus formed runs downwards and forwards to the right passes through the pancreatic notch, gains the portal fissure of the liver and divides into branches to supply the liver with functional blood.