ABSTRACT
Ulcerative colitis is an inflammation of the rectum mainly, which can extend up the colon. The aetiology is uncertain but environmental factors, HLA B27 and autoimmunity appear to play a part. UC involves the mucosa with superficial ulceration, exudation and pseudopolyposis (ulcers with oedematous tags of mucosa between them). Because the bowel wall is oedematous and rigid, there is loss of the normal haustrations seen on Xray. Even though there is inflammation of the bowel, it does not adhere to other intraabdominal viscera, and thus fistulation is not a feature.
