The liver is the second-largest organ in the human body. Traditionally, the anatomy
of the liver has been described on the basis of its external appearance/gross anatomy.
However, with the increase in surgical procedures, for example resection and transplant,
the need for a more functional description of the liver based on its vascular and
biliary architecture evolved. Different models of functional anatomy of the liver
have been described in the literature in the past, but Couinaud’s model of functional
anatomy of the liver is the most popular. The liver has dual vascular supply, with
most of its supply coming from the portal vein and the remainder through the hepatic
artery. In this article, we outline the functional anatomy of the liver along with
its blood supply.