A small bulge below the rib cage may be caused by an abdominal hernia, gastrointestinal obstruction, abdominal wall tumor and other causes. 1. Abdominal hernia: a history of abdominal trauma or abdominal wall dysplasia can lead to a weaker abdominal wall below the ribs, which may cause the intestines in the abdominal cavity to protrude to the surface of the body in this area, forming a mass. 2. Gastrointestinal obstruction: In the case of gastrointestinal obstruction, intestinal, gastric or peristaltic waves may appear around the lower part of the ribcage, and thus a bulge may appear in this area. 3. Abdominal wall tumor: if there is a tumor lesion of the abdominal wall, such as fibromatous or lipomatous lesion in the abdominal wall, it will also cause the bulge in the area. If there are bulges under the rib cage, you should consult the doctor as soon as possible, improve the examination and standardize the treatment under the doctor’s guidance.