An inguinal hernia is a hernia in the abdominal wall.
An inguinal hernia happens when contents of the abdomen—usually fat or part of the small intestine—bulge through a weak area in the lower abdominal wall. The abdomen is the area between the chest and the hips. The area of the lower abdominal wall is also called the inguinal or groin region.
Two types of inguinal hernias are
- indirect inguinal hernias, which are caused by a defect in the abdominal wall that is congenital, or present at birth
- direct inguinal hernias, which usually occur only in male adults and are caused by a weakness in the muscles of the abdominal wall that develops over time
Inguinal hernias occur at the inguinal canal in the groin region.
Males are much more likely to develop inguinal hernias than females. About 25 percent of males and about 2 percent of females will develop an inguinal hernia in their lifetimes. Some people who have an inguinal hernia on one side will have or will develop a hernia on the other side.
People of any age can develop inguinal hernias. Indirect hernias can appear before age 1 and often appear before age 30; however, they may appear later in life. Premature infants have a higher chance of developing an indirect inguinal hernia. Direct hernias, which usually only occur in male adults, are much more common in men older than age 40 because the muscles of the abdominal wall weaken with age.
People with a family history of inguinal hernias are more likely to develop inguinal hernias. Studies also suggest that people who smoke have an increased risk of inguinal hernias.
The cause of inguinal hernias depends on the type of inguinal hernia.
Indirect inguinal hernias: A defect in the abdominal wall that is present at birth causes an indirect inguinal hernia.
During the development of the fetus in the womb, the lining of the abdominal cavity forms and extends into the inguinal canal. In males, the spermatic cord and testicles descend out from inside the abdomen and through the abdominal lining to the scrotum through the inguinal canal. Next, the abdominal lining usually closes off the entrance to the inguinal canal a few weeks before or after birth. In females, the ovaries do not descend out from inside the abdomen, and the abdominal lining usually closes a couple of months before birth.
Sometimes the lining of the abdomen does not close as it should, leaving an opening in the abdominal wall at the upper part of the inguinal canal. Fat or part of the small intestine may slide into the inguinal canal through this opening, causing a hernia. In females, the ovaries may also slide into the inguinal canal and cause a hernia.
Indirect hernias are the most common type of inguinal hernia. Indirect inguinal hernias may appear in 2 to 3 percent of male children; however, they are much less common in female children, occurring in less than 1 percent.
Direct inguinal hernias: Direct inguinal hernias usually occur only in male adults as aging and stress or strain weaken the abdominal muscles around the inguinal canal. Previous surgery in the lower abdomen can also weaken the abdominal muscles.
Females rarely form this type of inguinal hernia. In females, the broad ligament of the uterus acts as an additional barrier behind the muscle layer of the lower abdominal wall. The broad ligament of the uterus is a sheet of tissue that supports the uterus and other reproductive organs.
The first sign of an inguinal hernia is a small bulge on one or, rarely, on both sides of the groin—the area just above the groin crease between the lower abdomen and the thigh. The bulge may increase in size over time and usually disappears when lying down.
Other signs and symptoms can include:
- discomfort or pain in the groin—especially when straining, lifting, coughing, or exercising—that improves when resting
- feelings such as weakness, heaviness, burning, or aching in the groin
- a swollen or an enlarged scrotum in men or boys
Indirect and direct inguinal hernias may slide in and out of the abdomen into the inguinal canal. A health care provider can often move them back into the abdomen with gentle massage.
A health care provider diagnoses an inguinal hernia with:
- a medical and family history
- a physical exam
- imaging tests, including x-rays
Repair of an inguinal hernia via surgery is the only treatment for inguinal hernias and can prevent incarceration and strangulation. Health care providers recommend surgery for most people with inguinal hernias and especially for people with hernias that cause symptoms. Research suggests that men with hernias that cause few or no symptoms may be able to safely delay surgery until their symptoms increase.3, 6 Men who delay surgery should watch for symptoms and see a health care provider regularly. Health care providers usually recommend surgery for infants and children to prevent incarceration.1 Emergent, or immediate, surgery is necessary for incarcerated or strangulated hernias.
A general surgeon—a doctor who specializes in abdominal surgery—performs hernia surgery at a hospital or surgery center, usually on an outpatient basis. Recovery time varies depending on the size of the hernia, the technique used, and the age and health of the person.
Hernia surgery is also called herniorrhaphy. The two main types of surgery for hernias are:
- Open hernia repair: The surgeon makes an incision in the groin, moves the hernia back into the abdomen, and reinforces the abdominal wall with stitches. Usually the surgeon also reinforces the weak area with a synthetic mesh or “screen” to provide additional support.
- Laparoscopic hernia repair: The surgeon makes several small, half-inch incisions in the lower abdomen and inserts a laparoscope—a thin tube with a tiny video camera attached. The camera sends a magnified image from inside the body to a video monitor, giving the surgeon a close-up view of the hernia and surrounding tissue. While watching the monitor, the surgeon repairs the hernia using synthetic mesh or “screen.”