Anatomy of the portal venous system with the liver retracted superiorly and D1, D3, D, jejunum and transverse colon removed.

Original diagram from Gray's anatomy, now out of copyright. Diagram of the basilar artery and circle of willis.This diagram has been reproduced from Gray's Anatomy 20th US edition which has now lapsed into the public domain (https://en.wikipedia.org/wiki/Portal_vein#/media/File:Gray591.png).