Intrahepatic branching patterns of portal vein. A study by corrosion cast.
Eighty-five corrosion casts of human portal veins were studied. The following observations were made: (1) In 88% of the cases, the portal vein divided into right and left branches, and in 12% of the cases, it divided into the left branch of the portal vein and anterior and posterior segmental n:veins; (2) Anterior and posterior segmental veins were branches of the right branch of the portal vein in 88% of the cases and arose directly from the portal trunk in 12% of the cases. In all cases, the anterior and posterior segmental veins in turn divided into superior and inferior area veins. (3) The left branch of the portal vein underwent a sharp kink leading into two parts: pars transversa nad pars umbilicalis. (4) The lateral superior area vein either sprang from the left side of the kink (69%), or from pars transversa near the kink (16%), or from the left side of pars umbilicalis near the kink (14%). The lateral inferior area vein arose from the left side of pars umbilicalis in all cases. (5) The medical segmental veins originated from the right side of pars umbilicalis. The number of branches varied from two to four. Further division of these into area branches were not fixed. (6) The right portion of the caudate lobe received portal blood either from the pars transversa (68%), or from the right branch of portal trunk (14%), or from the portal trunk (18%). The left portion of the caudate lobe received portal blood always from the pars transversa of the left trunk. (7) The branches to the caudate process arose from right branch of the portal vein in the majority of cases (72%). In the rest of the cases, these arose either from portal trunk (16% cases) or from pars transversa of the left trunk (12% cases).