Umbilical hernia refers to an abdominal external hernia in which abdominal contents protrude through a weak and defective umbilical ring. It is a general term for abdominal external hernias occurring at the umbilicus. Hernias that protrude through the umbilical ring are called umbilical hernias. The umbilicus is located in the central part of the abdominal wall, and it is the last part of the abdominal wall to close during embryonic development. At the same time, the umbilicus lacks fatty tissue, which allows the outermost skin and fascia of the abdominal wall to be directly connected to the peritoneum, making it the weakest part of the entire abdominal wall. Abdominal contents are prone to protrude at this location, forming an umbilical hernia. During the fetal period of humans, two arteries, one vein, the vitelline duct, and the umbilical urachus connect the fetus to the mother through the umbilical ring to obtain nutrition. Before and after the birth of the fetus, the above structures gradually close, and a umbilical depression is formed when the umbilical ring closes. If the closure is incomplete or delayed, malformations and hernias may occur immediately after the birth of the fetus. Hernias that protrude from the umbilical ring are called umbilical hernias. Clinically, there are two types: infantile umbilical hernia and adult umbilical hernia. The former is much more common than the latter.
Infantile umbilical hernia is a congenital disease in which abdominal contents protrude outward through the umbilical ring, with an incidence rate second only to congenital inguinal hernia, at approximately 2.6%. Girls are more prone than boys, and the incidence rate is relatively high in premature infants and low-birth-weight infants. It has a familial tendency and is related to race, and chronic constipation and crying in infants can also promote the occurrence of umbilical hernia. Adult umbilical hernia is generally a后天性疾病, accounting for 6% of all adult abdominal wall hernias, with the main cause being increased intra-abdominal pressure, such as multiple pregnancies, chronic cough, ascites, etc. This disease often occurs in middle-aged obese women, with a male-to-female ratio of about 1:3. The hernia contents are mostly omentum, followed by small intestine, colon, and so on. Adult umbilical hernia cannot heal spontaneously and has the risk of incarceration, so it should be treated actively with surgery.