Classification of portal vein tributaries in Thai cadavers including a new type V

Purpose To compare portal vein tributaries in Thai with Thompson classification. Methods In 211 Thai cadavers, abdominal regions were dissected to identify the portal veins and their tributaries. The subjects were classified into types based on modes of drainage of the left gastric and inferior mesenteric veins. Percentages of all types of venous drainage were counted. Results There are four types of portal tributaries as defined by Thompson, type I_47.87 %, type II_13.27 %, type III_7.58 %, and type IV_29.86 %. There were 1.42 % of whose inferior mesenteric veins entered the joining angle of the superior mesenteric and splenic veins, and were classified as type V. The left gastric vein mostly drained into the portal vein in 79.15 %, while the inferior mesenteric vein emptied into the splenic vein mainly in 55.45 %. Conclusions A new variance of portal tributaries in Thai cadavers is reported. The variations of portal vein formations are critical for liver surgery and interventional radiological procedures.