The pudenal nerve is the nerve that innervated the area rectum and the area around the anus. It also innervates the area between the legs and provides the primary source of sensation to the genitalia in both men and women. Injury to this nerve can cause loss of sensation and severe pain in these important areas. Blunt trauma to the buttocks of perineum (area between the legs), extensive cycling, or difficult childbirth involving a bad vaginal tear or even an episiotomy are common causes of pudendal nerve injury.