Unusual arterial supply of the segment IV with interlobar bridge and right replaced hepatic artery: a case report

A replaced right hepatic artery (RHA) arising from the superior mesenteric artery and an interlobar parenchymal bridge over the sagittal fissure have been observed on a 64-year-old formalin-fixed male cadaver in the anatomy laboratory. As we had followed a detailed segmental anatomy, we encountered an arterial distribution of segment IV featuring a different pattern from the literature so far. According to our observations, the segment I is supplied by both left (LHA) and middle (MHA) hepatic arteries; the segments II and III are supplied by the LHA while the segment IV is supplied by both the MHA and replaced RHA. The segments V-VIII are supplied only by the replaced RHA. The case emphasizes the importance of arterial variations of liver in terms of the surgical procedures during the liver transplantation, hepatic resections, hepatic tumours, and etc. Our discussion focuses to the arterial supply of the segment IV and possible complications it may cause during/after the liver operations.