the surgical formation of an artificial anus by making an opening from the colon through the abdominal wall. A colostomy may be performed in order to decompress an obstructed colon; to divert the fecal stream after traumatic injury or when resectioning an inflammatory, obstructive, or perforated lesion; to replace the anus as the distal opening of the gastrointestinal tract when the distal colon or rectum is removed; and to promote internal healing. Colostomies may be temporary or permanent. A sigmoid colostomy, which is the most common type of permanent colostomy, requires no appliances (although a light pouch is sometimes worn for reassurance) and allows an individual to lead a life that is in every way normal except for the route of fecal evacuation.