A person with a hernia has a piece of intestine that protrudes through an abnormal opening in the muscles of the abdominal wall. The protruding intestine forms a bulge under the skin.

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. About 75 percent of hernias occur in the groin.