The dorsal sector of human liver: embryological, anatomical and clinical relevance.

The dorsal liver sector has been recognized as the parenchyma surrounding the vena cava and is quite independent of the remaining liver. It is that part of the organ in which the hepatic portion of the vena cava develops and its venous outflow remains strictly connected with the vena cava by means of multiple, not dissectable effluents as well as with the main hepatic veins. Therefore, this sector is a major shunt between the main hepatic veins and the inferior vena cava, which enlarges and ensures venous drainage for survival in cases of Budd-Chiari syndrome. The dorsal sector consists of two segments: a left one (segment I) corresponding roughly to the caudate lobe and a right one (segment IX) in front and on the right of the vena cava, including the so-called caudate process. The identification of a dorsal liver sector and its detailed anatomy is of primary importance for surgical practice, since cholangiocarcinoma of bile duct hilar confluence extends to the dorsal sector and makes resection of this sector necessary for efficient therapy and due consideration of the pedicles of segment I and IX is required to perform successful hemihepatectomy as well as liver partition for split liver grafting.