What is a hernia?

A hernia is the protrusion of an organ or part of an organ through the wall of the cavity that normally contains it. A hernia occurs when there is a weakness or tear in your abdominal wall as a result of aging, injury, a previous surgical incision, or a condition present at birth.

Hernias generally grow larger due to pressure on them, such as a loop of your intestine or fatty tissue pushing into the weak abdominal tissue or tear. The result is a sac that forms in the abdominal wall. You may or may not see a bulge at this point.

As more abdominal contents push into the sac, a bulge will appear. Sometimes the bulge can be flattened out by lying down or pushing against it. Though a hernia at this stage - known as a reducible hernia - is not an emergency situation, you will likely still need surgery to repair it.

If the intestine gets trapped, or is non-reducible, it is called an incarcerated hernia, and can be quite painful. The bulge cannot ordinarily be flattened out and immediate surgery may be needed. A hernia that becomes tightly trapped, or strangulated, loses blood supply, blocks intestinal flow, and requires emergency surgery.

Unfortunately, a hernia won't go away on its own. In fact, hernias typically get worse over time, making hernia repair surgery the standard of care.

Do you have a hernia? Learn about hernia signs and symptoms.

How a Hernia Develops

Wall Weakens or Tears The abdominal lining bulges out through a weak area and begins to form a hernia sac. The sac may contain fat, intestine, or other tissues. At this point the hernia may or may not cause a visible bulge.

Intestine Pushes into the Sac As the intestine pushes further into the sac, it forms a visible bulge. The bulge may flatten when you lie down or push against it. This is called a reducible hernia and does not cause any immediate danger.

Intestine May Become Trapped The sac containing the intestine may become trapped (incarcerated). If this happens, you won't be able to flatten the bulge. You may also have pain. Prompt treatment may be needed.

Intestine May Be Strangulated If the intestine is tightly trapped, it becomes strangulated. The strangulated area loses blood supply and may die. This can cause severe pain and block the intestine. Emergency surgery is needed to relieve the blockage.

Who can get a hernia?

In the United States about 800,000 people per year undergo surgery to repair inguinal hernias (also called groin hernias) and another 500,000 undergo surgery to repair ventral hernias (abdominal hernias not in the groin area).

While it's difficult to predict when and where a hernia will occur, the lifetime risk of inguinal hernia for men is 27%. Direct inguinal hernias typically occur in men over 40. Men may also experience any type of ventral abdominal hernia, including incisional, epigastric, and umbilical.

Hernias occur less frequently in women, with the lifetime risk of inguinal hernia in women being 3%. Women are at greater risk than men for femoral hernias, or may require surgical repair for ventral abdominal hernias.

One type of ventral hernia, the umbilical hernia, can occur in infants and children. This can be the result of an abdominal wall defect that is present at birth. Children can also get an indirect inguinal hernia, causing a bulge that can be seen and felt.

How are hernias treated? Read about your options.