Sigmoidoscopy is an examination of the bottom one-third of your large intestine, including your rectum and the bottom part of your colon. To do this exam, your doctor uses a sigmoidoscope—a flexible viewing tube with a light and a lens or video camera on one end, and an eyepiece or video monitor on the other. The sigmoidoscope allows your doctor to see the inside of your bowel through fiber optic technology.
During sigmoidoscopy, your doctor can check for cancer, ulcers and abnormal growths called polyps. The procedure usually takes less than 15 minutes, and can be done in your doctor's office. There is usually very little discomfort because the sigmoidoscope is lubricated and bends easily.