Anatomy · Abdomen and Pelvis

Portal vein: formation, tributaries and portosystemic anastomoses

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  • Portal vein: valveless venous trunk draining the abdominal and pelvic alimentary tract (except the lower anal canal), gallbladder, pancreas and spleen into the liver.
  • It begins as a vein from the capillary bed of the gut and terminates like an artery in the hepatic sinusoids, carrying about 80% of hepatic blood flow.

Formation, Course and Branches

Course, from formation to termination:

  1. Neck of the pancreas: formed by union of the splenic vein and superior mesenteric vein, at the level of the L2 vertebra.
  2. First part of the duodenum: ascends behind it.
  3. Right free edge of the lesser omentum: enters here.
  4. Porta hepatis: ends by dividing into right and left branches.