Splenic vein is a tributary of the portal circulation that drains blood from the spleen (as suggested by its name). It forms a major originating tributary for the portal vein.
Origin, course and termination:
Splenic vein begins at the hilum of spleen by union of several small veins. It is then joined by the short gastric and left gastroepiploic veins.
After its origin, it passes to the right within the splenicorenal ligament and runs behind the pancreas below the splenic artery.
It ends by joining the superior mesenteric vein behind the neck of the pancreas. This union forms the portal vein.
Splenic vein is joined by veins from the pancreas and the inferior mesenteric vein.