Contribution to the study of anatomical variations in portal system formation

Abstract

The portal system is formed by veins which drain the blood from a large part of the digestive system to the liver. According to the classic description, the portal vein is formed by the junction of the superior mesenteric vein and the splenic vein. The inferior mesenteric vein runs into the splenic vein. The anatomical variations of the veins are frequent and the literature data are conflicting. The purpose of this study is to evaluate the portal system in cadaver and compare the results with the ones from the literature. From the 56 cadavers that were analised, 75% (n=42) presented the classic description and 25% (n=14) presented some variation. Among them, 21% (n=12) corresponded to the junction of the inferior mesenteric vein with the superior mesenteric vein and 3,6% (n=2) showes the union of the inferior mesenteric vein in the junction point of the splenic and superior mesenteric veins in order to form the portal vein. We can conclude that the most frequent situation is the junction of the inferior mesenteric vein with the splenic vein. The main variation in this study was the junction of the inferior mesenteric vein with the superior and the confluence of the three veins in portal vein formation represents a less frequent variation.