accessory hepatic vein

An accessory hepatic vein is an additional blood vessel that returns deoxygenated blood from the liver to the inferior vena cava. It supplements the main hepatic veins (right, middle, and left) in draining venous blood from hepatic segments.

Accessory hepatic veins are found within or at the surface of the liver, typically draining smaller or accessory portions of hepatic tissue that do not drain via the three main hepatic veins. They enter the inferior vena cava directly, usually inferior to the main hepatic vein ostia.

The accessory hepatic vein returns blood that has passed through the liver's sinusoids back into the systemic venous circulation via the inferior vena cava. It ensures complete venous drainage of hepatic tissue that is not adequately served by the principal hepatic veins.

Budd-Chiari syndrome — thrombosis or obstruction of the hepatic veins — can affect accessory hepatic veins as well as the main vessels, leading to hepatic congestion and potential liver failure. In liver transplantation and hepatic surgery, identification of accessory hepatic veins is important to ensure complete vascular control.

The three main hepatic veins (right, middle, left) drain the major lobar segments of the liver, while accessory hepatic veins are smaller additional vessels that drain minor or accessory hepatic territories. Their presence is anatomically variable but clinically relevant during hepatic procedures.