Endoscopy is a visual examination of the gastrointestinal tract using a lighted, flexible fiberoptic or video endoscope. In gastroenterology, this procedure is called either gastroscopy, the examination of the upper gastrointestinal tract; sigmoidoscopy, the visual examination of the rectum and sigmoid colon; or colonoscopy, which is the examination of the entire lower gastrointestinal tract.
The flexible endoscope is a remarkable piece of equipment that can be gently directed and moved around the bends and turns of the gastrointestinal tract. The flexible video endoscopes have a tiny, color TV camera with a wide-angle lens at the end. Electronic signals are then transmitted up the scope to the computer which then displays the image on a large video screen. An open channel in these scopes allows other instruments to be passed through in order to take tissue samples, remove polyps, and perform other exams.