A hernia is a sac formed by the lining of the abdominal cavity (peritoneum). The sac comes through a hole or weak area in the strong layer of the belly wall that surrounds the muscle. This layer is called the fascia.
Which type of hernia you have depends on where it is:
- Femoral hernia is a bulge in the upper thigh, just below the groin. This type is more common in women than men.
- Hiatal hernia occurs in the upper part of the stomach. Part of the upper stomach pushes into the chest.
- Incisional hernia can occur through a scar if you have had abdominal surgery in the past.
- Umbilical hernia is a bulge around the belly button. It occurs when the muscle around the belly button does not close completely after birth.
- Inguinal hernia is a bulge in the groin. It is more common in men. It may go all the way down into the scrotum.

Alternative Names
Hernia - inguinal; Inguinal hernia; Direct and indirect hernia; Rupture; Strangulation; Incarceration
Causes
Usually, there is no clear cause of a hernia. Sometimes, hernias occur with:
- Heavy lifting
- Straining while using the toilet
- Any activity that raises the pressure inside the belly
Hernias may be present at birth, but the bulge may not be noticeable until later in life. Some people have a family history of hernias.
Babies and children can get hernias. It happens when there is weakness in the belly wall. Inguinal hernias are common in boys. Some children do not have symptoms until they are adults.
Any activity or medical problem that increases pressure on the tissue in the belly wall and muscles may lead to a hernia, including:
- Chronic constipation and pushing hard (straining) to have a bowel movement
- Chronic cough
- Cystic fibrosis
- Enlarged prostate, straining to urinate
- Extra weight
- Fluid in the abdomen (ascites)
- Heavy lifting
- Peritoneal dialysis
- Poor nutrition
- Smoking
- Overexertion
- Undescended testicles