An abscess in the space between the sheet of muscle that assists in control of the rectum (levator ani) and the pelvic bone. It may occur spontaneously, but is often secondary to an anal fissure, thrombosed haemorrhoids, or other disease of the anus (such as Crohn’s disease). Symptoms are severe throbbing pain near the anus with swelling and fever; it may cause an anal fistula. Pus is drained from the abscess by surgical incision.
Subjects: Medicine and Health.