Abstract
The definition and extent of the human caudate lobe in the liver is unclear, and thus, the anatomy of the caudate lobe was studied using 23 corrosion liver casts, with special reference to the portal venous and biliary branches. These branches and their ramification type in the caudate lobe showed that this lobe includes: (1) the Spiegel lobe; (2) the paracaval portion; and (3) the caudate process portion. The three portions often have their own independent branches; for example, the portal venous and biliary branches of the Spiegel lobe were ramified mainly from the left-side tract, whereas those of the caudate process portion were ramified from the right-side tract. The portal venous branches of the paracaval portion were ramified mainly from the left portal vein, while the biliary branches of this portion drained into the right and left biliary tracts at almost equal frequencies. In most cases, the peripheral branches reached the liver surface beneath the diaphragm. Thus, the present division of the caudate lobe into three portions could make the extent of the caudate lobe clear and is considered logical from a clinical viewpoint.