Liver thickness refers to the thickness and length of the liver. By measuring the thickness and length of the liver, it is possible to determine whether the liver is enlarged or shrunken, and to make a preliminary judgment on whether there is a lesion in the liver and the possible causes. For example, the maximum diagonal diameter of the right liver usually does not exceed 12-14 cm, and the anterior-posterior diameter does not exceed 8-10 cm; the thickness of the left liver does not exceed 5-6 cm, and its length does not exceed 5-9 cm; and the length and thickness of the caudate lobe of the liver usually do not exceed 4-5 cm; and the clinical causes of the liver’s enlargement and increase in its thickness mainly include infections, immunity, heredity, tumors, cysts, metabolic anomalies, cholestasis, and stagnant lesions. The causes of liver enlargement and thickness increase include infection, immunity, genetics, tumor, cyst, metabolic abnormality, cholestasis, and bruising lesions, etc., while liver shrinkage is mainly seen in advanced cirrhosis or acute severe hepatitis. After liver thickness and length are measured, other ancillary tests can be performed to evaluate the specific lesion.