The common clinical term for the hepatic hilar should refer to the first hepatic hilar, and the structures that do not enter or exit through the first hepatic hilar are the hepatic veins. In addition to the first portal, there are also the second and third portals. 1. Porta I: This refers to the location on the visceral surface of the liver where the various ducts and nerves enter and exit the liver. It includes the hepatic artery, portal vein, hepatic ducts, nerves of the liver and hepatic lymphatics. It mainly provides blood supply to the liver, transports nutrients absorbed from the gastrointestinal tract to the liver for preliminary processing, and drains bile secretion to the gallbladder and common bile duct. 2. Second hepatic hilar: It refers to the area behind the liver where the hepatic vein leaves the liver. Its main function is to drain the blood flow from the liver to the inferior vena cava and finally back to the heart. 3. Third hepatic hilar: refers to some small veins and short blood vessels of the liver that do not pass through the hepatic vein but directly into the inferior vena cava. These veins and vessels are small and numerous, which can easily lead to bleeding if no attention is paid during the operation.