From the Guidelines
The liver's anatomy is complex, with a dual blood supply from the hepatic portal vein and hepatic artery, and a network of vessels that include the central veins, hepatic veins, and inferior vena cava, as well as bile ducts that collect bile produced by hepatocytes 1.
Liver Structure
The liver is a large, reddish-brown organ located in the upper right quadrant of the abdomen, just beneath the diaphragm. It weighs approximately 1.5 kg in adults and is divided into four lobes: the larger right and left lobes, and the smaller caudate and quadrate lobes. The liver's surface is covered by a fibrous capsule called Glisson's capsule. Internally, the liver is organized into functional units called lobules, which are hexagonal structures centered around a central vein.
Blood Supply
The liver receives blood from two major vessels:
- the hepatic portal vein, which delivers nutrient-rich blood from the digestive organs (about 75% of blood supply)
- the hepatic artery, which provides oxygen-rich blood from the heart (about 25% of blood supply) 1. After blood circulates through the sinusoids, it collects in the central veins, which merge to form hepatic veins that ultimately drain into the inferior vena cava.
Vascular Connections
Some key points about the vascular connections of the liver include:
- The portal triad, located at the corners of each lobule, contains branches of the hepatic portal vein, hepatic artery, and bile duct.
- The hepatic artery and portal vein are crucial for the liver's function, and injuries to these vessels can have significant consequences, including hemorrhage and liver necrosis 1.
- The hepatic veins drain into the inferior vena cava, and injuries to these vessels can be difficult to repair, with high mortality rates 1.
Bile Ducts
The liver also contains bile ducts that collect bile produced by hepatocytes. These ducts merge to form the common hepatic duct, which joins with the cystic duct from the gallbladder to form the common bile duct, which empties into the duodenum. This dual blood supply and complex vascular architecture allow the liver to efficiently perform its numerous functions, including metabolism, detoxification, protein synthesis, and bile production.
From the Research
Liver Anatomy
The liver has a complex vascular supply, which involves the inflow of oxygenated blood through the hepatic artery and deoxygenated blood through the portal vein, as well as the outflow of deoxygenated blood through the hepatic veins to the inferior vena cava 2. The liver's vascular anatomy can be divided into two main systems: the hepatic artery (systemic circulation) and the portal vein (portal circulation) 3.
Vascular Supply
- The hepatic artery provides oxygenated blood to the liver 2
- The portal vein provides deoxygenated blood to the liver 2
- The hepatic veins drain deoxygenated blood from the liver to the inferior vena cava 2
Spatial Relationship between Intrahepatic Artery and Portal Vein
The spatial relationship between the intrahepatic artery and portal vein can vary, with different classifications based on the fusion image of CT-arterial portography (CTAP) and CT-angiography (CTA) 4. These classifications include:
- Anterior and posterior hepatic artery running superior and inferior to anterior portal vein, respectively
- One anterior hepatic artery running superior to and another one running inferior to anterior portal vein
- Anterior and posterior hepatic arteries running superior to anterior portal vein
- Anterior and posterior hepatic arteries running inferior to anterior portal vein
- One posterior hepatic artery running superior to and another one running inferior to anterior portal vein
Liver Functions
The liver plays a critical role in various physiological processes, including: