Hepatic venous plexuses on the right border of the caudate lobe against the right liver in a liver cast.

Identifying the right border of the caudate lobe against the right liver is clinically important; however, this remains challenging. As the paracaval portion (PC) of the caudate lobe is adjacent to segment 8 of the right liver, we dissected a liver cast made from epoxy resin and colored dye to define the right border of the PC against segment 8. On the right border of the PC, two major venous plexuses appearing as bouquet-shaped branches joined the inferior vena cava and the middle hepatic vein, forming short hepatic veins, whereas the venous plexuses in segment 8 joined the right hepatic and the vein inferior vena cava. These venous plexuses in PC and segment 8 created a zigzag boundary plane, which coincided with the boundary found between the caudate lobe and the right liver. Moreover, no longitudinal venous branch was found between the PC and segment 8 in the liver cast.