The ilioinguinal nerve branches off the first lumbar nerve, which is near the lower back. It branches down the body through the second and third abdominal muscles and communicates with the iliohypogastric nerve, whose main function is to regulate the diaphragm (a muscle that helps with breathing) and the areas around it.

The ilioinguinal nerve moves further down the body, eventually branching out into the upper part of the thigh muscles. It also reaches the mons pubis and labia majora, both parts of the groin. The nerve provides sensation to these areas.

During certain abdominal operations, such as hernia surgery, the ilioinguinal nerve must be carefully avoided, as severing this nerve will lead to pain in the thighs and labia majora and a weakening of the local muscle fibers, which can lead to a direct inguinal hernia. An inguinal hernia is a bulging of soft tissue through weakened abdominal muscle walls into the lowest part of the abdomen or the groin. This condition is far more common in men than in women.

Sometimes the ilioinguinal nerve may end at the iliohypogastric nerve. In this case, a branch of the iliohypogastric nerve will take over the nerve functions normally associated with the ilioinguinal nerve.