Left Hemiliver Medial Sector-Portal Venous Anatomy

Background: The aim of this study was to classify the left hemiliver medial sector portal branches on the basis of their site of origin and area that supply. The leading motive for this investigation was to contribute to the modern liver practice, especially to the respective and transplantation ones. Methods: The examined material consisted of 27 portobiliary casts performed by injection-corrosive method using adult cadaveric human liver specimens. During observation under magnifying lens were determined the site and kind of origin of medial sector portal branches, numerical frequency of segmental portobiliary elements and their relation. Results: According to the supplied area two distinct segmentssuperior IVa and inferior IVb were distinguished. At the level of each segment portal branches appeared as main, additional and newly ramified. As to their origin at the level of segment IVa the mixed origin (separate and common) was prevalent versus separate or only common origin 17/7/2 cases and portal branches were not observed in only one case in this segment. Also, at the level of segment IVb the mixed origin of portal branches was prevalent versus separate ones 19/8 cases. The incidence of newly ramified branches to segment IVa was 22.22% and to segment IVb 37.037%. At the level of segment IVa there were additional or newly ramified branches on the superior surface of umbilical portion of the left portal vein branch (37.037%) and only additional branches for segment IVb on the superior, as well as inferior surface of this portion (7.41%). Conclusion: In the left hemiliver medial sector portal branches supply two distinct segments-superior SgIVa and inferior SgIVb. At the level of each segment multiple branches with varied number appear as main, additional and newly ramified. According to their origin the branches may be either separate for each segment or additionally to the branches with separate origin common branches for both segments and only with common origin branches to the SgIVa.