Right hepatic artery

The right hepatic artery (RHA) is formed when the proper hepatic artery (PHA) bifurcates. The hepatic arteries provide 25% of the blood supply and 50% of the oxygen supply to the liver.

Gross anatomy

The proper hepatic artery bifurcates into the right and left hepatic arteries at or before reaching the porta hepatis. These are end arteries and supply the right and left halves of the liver respectively. The RHA passes upwards and turns to the right, crossing behind the common hepatic duct to enter Calots triangle ¹. It usually gives off the cystic artery within Calot’s triangle ^1,2 then turns upwards to enter the right lobe of the liver.

Within the liver, it divides into:

• anterior segmental branch which supplies segments V and VIII and usually supplies a branch to segment I ¹
• posterior segmental branch which supplies segments VI and VII ¹

Moynihan’s lump, also known as caterpillar lump, is the descriptive term when the RHA forms a sinuous tortuosity occupying the majority of Calots triangle and may be at risk of damage during a cholecystectomy. It often lies in close proximity with the gallbladder neck.

Variant anatomy

The RHA can be aberrant in one-third of cases, and is known to originate from the:

• superior mesenteric artery
• gastroduodenal artery
• right gastric artery
• celiac trunk

The RHA may also give rise to the middle hepatic artery, which usually arises from the LHA and supplies segments IVa and IVb.

An uncommon but important variant, the falciform artery, may arise from the RHA exiting the liver in the falciform ligament to supply part of the anterior abdominal wall.