A hernia occurs when there is a weakness or hole in the peritoneum, the muscular wall that usually keeps abdominal organs in place. This defect in the peritoneum allows organs and tissues to push through, or herniate, producing a bulge. The lump may disappear when the person lies down, and sometimes it can be pushed back into. Coughing may make it reappear.

Types

Hernias can commonly be found in the following areas:

Groin: a femoral hernia creates a bulge just below the groin. This is more common in women. An inguinal hernia is more common in men. It is a bulge in the groin that may reach the scrotum.

Upper part of the stomach: a hiatal or hiatus hernia is caused by the upper part of the stomach pushing out of the abdominal cavity and into the chest cavity through an opening in the diaphragm.

Belly button: a bulge in this region is produced by an umbilical or periumbilical hernia.

Surgical scar: past abdominal surgery can lead to an incisional hernia through the scar.

Causes

With the exception of an incisional hernia (a complication of abdominal surgery), in most cases, there is no obvious reason for a hernia to occur. The risk of hernia increases with age and occurs more commonly in men than in women.

A hernia can be congenital (present at birth) or develop in children who have a weakness in their abdominal wall.

Activities and medical problems that increase pressure on the abdominal wall can lead to a hernia. These include:

.straining on the toilet (due to long-term constipation, for example)

.persistent cough

.cystic fibrosis

.enlarged prostate

.straining to urinate

.being overweight or obese

.abdominal fluid

.lifting heavy items

.peritoneal dialysis

.poor nutrition

.smoking

.physical exertion

.undescended testicles