Venous hepatic segmentation in dogs (Canis lupus familiaris-L. 1758)

The external shape of the liver is varied and determines specific vascular arrangements. This morphological relationship is important to establish hepatic segmentation in different species submitted to surgeries that aim to preserve a larger area of liver parenchyma. After observing 60 livers injected with Neoprene Latex and three plastic moulds obtained by corrosion, eight hepatic venous segments were identified, drained by six hepatic veins agrouped into segmental veins, which drained one sector (segments I, VI, VII and VIII) and intersegmental veins, which drained more than one sector (segments II/III and IV/V). They were described as follows: left intersegmental vein, formed by a segmental vein from the papillary process (segment I), two to three lateral left segmental veins that drained the segment II, and one to five left paramedian segmental veins that drained the segment III; sagittal intersegmental vein, formed by the confluence between segmental vein of the quadrate lobe (segment IV) and the medial right paramedian segmental vein, which derived from the segment V; lateral right paramedian vein drained the dorsocranial sector of the segment VI; the lateral right segmental vein, formed by one to four vessels that drained segment VII, and the segmental vein of the caudate process, which drained the segment VIII. Understanding the number and disposition of the hepatic veins in lobate livers is essential to reduce bleeding risks in surgeries. The nomenclature based on segmentation analogy of non-lobate liver could be less confusing and, therefore, be more useful in the surgical approaches of lobate livers.