The liver is divided into five lobes and eight segments. 1. Five lobes: the five lobes are the caudate lobe, the left extrahepatic lobe, the left inner lobe, the right anterior lobe, and the right posterior lobe, which are divided into lobes according to the distribution of the portal vein and the hepatic vein in the liver. 2. Eight segments: I~VIII are: caudate lobe, upper segment of left extrahepatic lobe, lower segment of left extrahepatic lobe, left inner lobe, lower segment of right anterior lobe, lower segment of right posterior lobe, upper segment of right posterior lobe, upper segment of right anterior lobe. The segmentation of the liver is of guiding significance when doing liver surgery for segmental resection or lobectomy. It can also be divided by some anatomical structures, such as the middle hepatic vein – a marker to differentiate between the left and right liver when doing ultrasound; the right hepatic vein – divides the right lobe of the liver into the right anterior and right posterior lobes; and the right branch of the portal vein – the right branch of the portal vein. – is the sign that distinguishes the upper and lower segments of the right anterior and posterior lobes of the liver. For more information on human anatomy, you can refer to your specialty textbook.