Sigmoidoscopy(Proctoscopy) No tissue abnormalities are seen The patient is placed in a lateral or knee-chest position.  The well lubricated instrument is inserted into the anus and advanced to the sigmoid colon. To screen the Colon Cancer To investigate the source of unexplained rectal bleeding To evaluate the postoperative anastomosis of the colon To diagnose or monitor Inflammatory Bowel Disease Colitis Colorectal Cancer "Gay bowel syndrome" Crohn's Disease Irritable Bowel Syndrome Parasitic disease Intestinal Ischemia Adenomatous polyps Abscess Sigmoid volvulus. Uncooperative patient behavior Severe bleeding Suspected bowel perforation Peritonitis Toxic megacolon Acute Diverticulitis Parsitic ileus