An inguinal hernia occurs when a small portion of the bowel bulges out through the inguinal canal and into the groin. (The inguinal canal is a passage or opening through the muscles of the abdominal wall.) The bulge usually contains tissue lining the inside of the abdomen (belly) as well as fatty tissue from inside the belly. Or it may contain a loop of intestine.

There are two types of inguinal hernias:

• Direct inguinal hernias. These occur when a weak spot develops in the lower belly muscles. Often the cause of the hernia is not known. But the cause is often thought to be lifting, straining, or coughing. Or it may be being obese, pregnant, or constipated.
• Indirect inguinal hernias. These 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.