Hepatic veins

The hepatic veins are three large intraparenchymal veins which drain the liver substance into the inferior vena cava (IVC), named the right hepatic vein, middle hepatic vein and left hepatic vein. The veins are important landmarks, running in between and hence defining the segments of the liver. There are separate smaller veins draining the caudate lobe of the liver and hepatic venous anatomy can be highly variable.

Right hepatic vein

The right hepatic vein runs in the right hepatic fissure and drains segments V, VI, VII and VIII. The vertical plane of the right hepatic vein separates the segments VI and VII (posterior to the plane) from segments V and VIII (anterior to this plane).

Variant anatomy 

It is a single dominant vein in ~70% (range 60-78%) of individuals. There may be an early bifurcation, early trifurcation or even multiple right hepatic veins entering the IVC. Hence this may make it difficult to accurately deduce segmental anatomy of the liver.

Middle hepatic vein

The middle hepatic vein runs at the middle hepatic fissure and drains segments IVa, IVb, V and VIII. The vertical plane of the middle hepatic vein separates the segments V and VIII (posterolateral to this plane) from segments IVa and IVb (anteromedial to this plane).

Left hepatic vein

The left hepatic vein runs partially in the fissure for the ligamentum teres and the left hepatic fissure. It drains segments II, III, IVa and IVb. It is always located anterior to the left portal vein. The vertical plane of the left hepatic vein separates the segments IVa and IVb from segments II and III.

Caudate lobe veins

The highly variable caudate lobe veins (or a single vessel) drain directly into the IVC.