Liver size (hepatomegaly) can be caused by many diseases and is an important clinical sign. The normal liver size is 25cm in length x 15cm in upper and lower diameter x 16cm in anterior and posterior diameter. the average weight of the liver of adult males in China is 1342g and 1234g in females, accounting for about 1/50 of body weight. the liver of fetuses and newborns is relatively larger than that of adults, accounting for about 1/20 of body weight. the upper border of the normal liver is consistent with the diaphragmatic fornix, starting at the 7th rib in the right mid-axillary line, going to the 5th rib in the right mid-clavicular line, then to the left to the anterior median line. The upper border of the liver is in line with the diaphragmatic vault, starting from the 7th rib in the right mid-axillary line to the 5th rib in the right mid-clavicular line, then to the left to the junction of the anterior median line and crossing the sternal body and the saber process to the left mid-clavicular line. Diagnosis and differentiation of clinical symptoms of hepatomegaly 1. Viral hepatitis Viral hepatitis leading to hepatomegaly often has a history of close contact with patients with viral hepatitis, unclean diet or blood transfusion or drug injection. Clinical manifestations are malaise, lack of appetite, nausea, abdominal distension, pain in the liver area, etc. Signs include enlarged liver, pain in the liver area, jaundice, etc. Liver function tests have increased serum enzymatic activity, and serological tests can detect viral antigens or antibodies to various types of hepatitis (A, B, C, D, E, H, G). Toxic hepatitis is often preceded by a history of drug or poison exposure and followed by symptoms such as liver enlargement, fever, rash, pain in the liver area, and jaundice. Toxic hepatitis is also accompanied by other signs of organ function damage, eosinophilia in the peripheral blood, while the serum antigen or antibody test for each type of viral hepatitis is mostly negative. The symptoms usually return to normal after discontinuing the drug or stopping the exposure to the toxic substance, but the same symptoms appear again when the drug or toxic substance is exposed again. 3.hepatic abscess Liver abscess usually starts slowly, often with chills and fever due to obvious inflammation, then pain in the liver area, liver enlargement, smooth liver surface, pressure pain and percussion pain, corresponding abdominal wall often has edema, peripheral blood leukocyte and neutrophil count is increased. Ultrasound examination, radionuclide, CT scan and other auxiliary examinations can assist in the diagnosis, and diagnostic puncture examination is feasible if necessary. 4.Primary or metastatic hepatocellular carcinoma Patients with primary hepatocellular carcinoma are mostly above 40 years old, and males are more common, with slow onset. In primary hepatocellular carcinoma, serum alpha-fetoprotein value is often elevated, and serum AKP, γ-GT and carcinoembryonic antigen may also be elevated. Cancer foci can be detected by abdominal ultrasound, CT, radionuclide, MRI and other auxiliary examinations; in metastatic hepatocellular carcinoma, multiple cancer foci of different sizes can be seen in liver parenchyma by ultrasound and other examinations. 5.Liver cysts Patients with liver cysts often have no obvious clinical symptoms or only non-specific symptoms such as upper abdominal discomfort, which are mostly congenital and a few are acquired. Ultrasound, CT, MRI and other examinations can reveal liquid dark areas in the liver with clear edges, and strong echogenic light clusters are visible when calcification occurs. 6.Other The position of the liver is related to gender, age and body type, and can change to a certain extent with breathing, visceral activity and body position, falling in standing position and during inspiration, rising in supine position and during exhalation, and the difference between lifting and lowering is about 3cm during calm breathing. In children under 5 years old, people who drink more water, after meals, in the evening, after exercise, and those who have been living in plateau for more than 2 months, the liver is often 1 to 2cm below the rib edge and can be palpable, with sharp edges, soft texture, and no pressure pain. Sometimes the liver is palpated under the ribs not because it is large, but because it has shifted downward, which can be seen in menstruating women with flaccid abdominal walls, singing or playing people with overdeveloped diaphragmatic movements, emphysema, large right pleural effusions, and subdiaphragmatic abscesses. Sometimes enlarged gallbladder, transverse colon tumor, pancreatic cyst, gastric cancer, right renal prolapse, right hydronephrosis, right renal cyst, and pheochromocytoma can also be mistaken for hepatomegaly, but the respiratory mobility is not as great as that of the liver and the margins are not as clear as those of the liver, so the pathological hepatomegaly should be determined by combining the medical history, the location, morphology, texture of the liver, respiratory mobility, the presence of pressure pain, and other examination findings.