- Portal vein supplies 70% of blood flow to liver
- Formed from confluence of splenic and SMV at neck of pancreas
- IMV drains at right angles into splenic vein or sometimes directly into SMV
- Portal vein receives majority of venous drainage of gastrointestinal system
- Receives left and right gastric and superior pancreaticoduodenal veins
- Most of tributaries of portal vein enter on its sides or posteriorly
- Thus space can be created bluntly between PV/SMV and neck of pancreas
- Portal vein then ascends to join porta hepatis in free margin of epiploic foramen lying behind the CBD and hepatic artery
- At porta hepatis it divides into a shorter but wider right branch and longer but narrower left branch