Proctoscopy, Sigmoidoscopy, and Colonoscopy
Inspection of the intestinal tract is done by tubular endoscopes with appropriate illumination. The instrument for examination of the rectum is called a proctoscope. To examine the sigmoid colon, a device called a sigmoidoscope is used, which can visualize up to 25 cm from the anal verge. To examine the entire colon from the rectum to the cecum a device called a fiberoptic colonoscope is used. The sigmoidoscope or proctoscope can be either rigid or flexible. If a malignancy is suspected, tissue can be removed during the examination for histologic study.