Linda Martinez, age 13, of Glendale, Ariz., for her question:

WHAT CAUSE A HERNIA?

A hernia is a rupture. It is caused by a break in the cavity walls within the body.

Many organs of the body, like the lungs, heart or intestines, are inside hollow places called body cavities. Sometimes the wall of a cavity breaks, or ruptures, and part of the organ pushes through. Then the person has a hernia.

When used alone, the word generally means an abdominal hernia.

In this type, a loop of the bowel sticks out through the muscular wall of the abdomen.

The hernia often occurs at a weak point of the muscular wall. It usually pushes out a part of the inner lining of the abdomen, the peritoneum, and forms a hernial sac. This sac may be felt or seen underneath the skin of the abdomen.

Hernia results from many causes. An abdominal hernia sometimes results from lifting a heavy object, or from a strain or other injury.

Supports such as trusses may relieve abdominal hernias by keeping the bowel inside the abdominal wall. But usually the only cure for a hernia is an operation.