Portal vein is formed by the union of -

Ans. is 'b' i.e., Splenic and superior mesentric veins o Portal vein is formed by the union of the superior mesentric and splenic veins behind neck of pancreas at L2 level. Inferior mesentric vein drains into the splenic vein.o The portal vein is about 8 cm long. It is formed by the union of the superior mesenteric veins and the splenicvein behind the neck of the pancreas at the level of the second lumbar vertebra. The inferior mesenteric vein drains into the inferior mesenteric vein.Important facts about portal veino 8 cm longo The blood flow is slowo Stream line flow :- Blood in superior mesentric vein drains into right lobe of liver. Blood in splenic and inferior mesentric vein drains into left lobe.o RelationsInfraduodenal part Anterior Neck of pancreas Posterior I VCRetroduodenal partAnterior lst part of duodenum, bile duct, gastroduodenal arteryPosteriorIVCSupraduodenal partAnterior Hepatic artery, bile duct.Posterior IVC, separated by epiploic formeno Development of Portal vein :Infra-duodenal part - part of left vitelline vein distal to the dorsal ansatomosisRetro-duodenal part - dorsal anastomosis between two vitelline veinsSupra-duodenal part - cranial part of right vitelline veinThe portal vein receives the following veins :Splenic veinSuperior mesenteric veinLeft gastricRight gastricSuperior pancreatico-duodenalCysticParaumbilical veins