Ramification of the portal vein at the porta hepatis in humans.

The ramification of the portal vein at the porta hepatis was studied by anatomic dissection performed in 32 formalin fixed human livers. In all the specimens there were branches which ran towards the caudate lobe, arising from the portal vein and either from the left or the right portal branches. Tri- and quadrifurcation of the portal vein was observed. In 5 cases (16%) there were branches arising from left portal branch or portal vein and directed anteriorly to the quadrate lobe or to the region of the gall-bladder sulcus. These branches ranged from 1.0 to 6.0 mm in diameter. The portal caudate branches were divided into 3 groups. Group 1: Branches to the papillary process; 1 or 2 branches in 26 cases (82%), 3 or 5 branches in 3 cases (9%) and no branches in 3 cases (9%); Group 2: Branches to the vena cava region, including the left part of the caudate process; 1 or 2 branches in 30 cases (94%), 3 branches in 1 case (3%) and no branches in 1 case (3%); Group 3: Branches to the right part of the caudate process; 1 or 2 branches in 12 cases (37%), and no branches in 20 cases (63%).