An inguinal hernia occurs when a small portion of the bowel bulges out through the inguinal canal—a passage or opening through the muscles of the abdominal wall—into the groin. The bulge usually contains tissue lining the inside of the abdomen as well as fatty tissue from inside the abdomen or a loop of intestine.

There are two types of inguinal hernias:

• Direct inguinal hernias occur when a weak spot develops in the lower abdominal muscles. Often the cause of the hernia is not known, but lifting, straining, or coughing or being obese, pregnant, or constipated are often thought to be causes of hernias.
• Indirect inguinal hernias occur when the inguinal canal fails to close before birth. The hernia may appear in a male's scrotum or in the fold of skin at the opening of a female's vagina. This is the most common type of inguinal hernia, and it may occur at birth or later in life. Indirect hernias are more common in males.

Symptoms of an inguinal hernia may come on gradually or suddenly and may include a bulge in the groin or scrotum and discomfort, pain, or a feeling of heaviness. Other symptoms may develop if tissue in the hernia becomes trapped (incarcerated) or if the blood supply to the trapped tissue is cut off (strangulated).

An inguinal hernia may require surgery. In some cases, hernias that are small and painless may never need to be repaired.