Hernias can form in many places inside the body, but the most common areas are the abdomen and groin. In order for a hernia to form, there must be a hole, tear or weakened area in the layers of tissue that surround an organ. This abnormal weakness allows the organ to protrude through the hole or tear. In the groin or abdomen, the intestine protrudes through the weakened abdominal wall. The intestine forms a bulge underneath the skin.

Causes for weakness in the layers that surround organs include:

• The tissue that surrounds an organ develops abnormally in the womb.
• Injury
• Obesity
• Prior surgery
• Abdominal adhesions