also called a flexible sigmoidoscope. A thin, flexible, hollow, lighted tube about the thickness of a finger with a small video camera on the end. It is inserted through the rectum up into the lower part of the colon. The sigmoidoscope is connected to a TV monitor so the doctor can look at the inside of the rectum and the lower part of the colon for cancer or for polyps (small growths that can become cancer). See also colon, polyp, rectum, sigmoid colon, sigmoidoscopy.