A hard lump to the left of the navel, beating like a heart may be a normal physiologic phenomenon, the normal beating of the abdominal aorta. There may also be pathological phenomena, hard lumps may be abdominal aortic aneurysm or renal aneurysm. 1. Physiological phenomenon: generally thin people can feel the pulsation of the abdominal aorta from the left side of the navel, hard lumps are considered to be fecal matter. 2. Pathological phenomenon: (1) abdominal aortic aneurysm, the common cause is atherosclerosis, other rare causes are cystic degeneration of the middle layer of the artery, congenital dysplasia, etc., most of the patients are asymptomatic, and it is often found by chance during physical examination, and a swollen throbbing mass can be felt around the umbilicus, and there is sometimes a light pressure pain. (2) Renal artery aneurysm, mostly due to atherosclerosis or external damage, resulting in damage to the renal artery wall, usually no specific symptoms, found in the physical examination of the abdominal pulsating mass, most of them are accompanied by high blood pressure. The presence of a hard lump throbbing on the left side of the navel, it is recommended to be admitted to the hospital for examination to exclude the possibility of disease and treatment according to medical advice.