A half spherical mass in the umbilicus is soft, and a giant umbilical hernia may dangle downward. If the hernia contents are intestinal tubes, intestinal peristalsis may be seen. So, what are the causes of the symptoms of a half spherical lump in the umbilicus? Here is a brief introduction: Commonly known as “gas navel”, it is congenital and is one of the common diseases in newborns and infants. After the umbilical cord is shed, the umbilical scar area due to the fetal stage umbilical cord from the abdominal wall through, is a congenital weakness of the abdominal wall; in infancy, the two sides of the abdominal muscles are not completely together in the midline, leaving a defect, known in medicine as the umbilical ring. When the intra-abdominal pressure increases due to excessive crying, coughing, diarrhea, etc., the contents of the abdominal cavity, especially the small intestine, together with the peritoneum and skin of the abdominal wall, will gradually eject outward from the umbilicus, forming an umbilical hernia. In adults, umbilical hernia is less common. It may be associated with weakening of the scar tissue at the umbilical ring. Causes include pregnancy, chronic cough, and fluid accumulation in the abdominal cavity. The contents of the hernia are initially the greater omentum, followed by the small intestine, colon, etc. It is often due to extensive adhesions to the hernia sac wall, forming a multifocal gap.