A colonoscopy is a test where the endoscopist looks into your colon. The colon is sometimes called the large intestine or large bowel. The colon is the part of the gut which comes after the small intestine. The last part of the colon leads into the rectum where faeces (stools or motions) are stored before being passed out from the anus. A Flexible sigmoidoscopy inspects the left side of the colon alone and is less invasive.
A colonoscope is a thin, flexible, telescope. It is about as thick as a little finger. It is passed through the anus and into the colon. It can be pushed all the way round the colon as far as the caecum (where the small and large intestine meet). In most cases experienced endoscopists can view the last part of the small bowel as well.
Using tiny instruments passed down the colonoscope it is possible to remove polyps and other lesions of the bowel, use laser and heat treatments to lesions, and even position devices to hold open tumours which are narrowing the bowel.
Using tiny instruments passed down the gastroscope it is possible to remove treat bleeding ulcers and other lesions of the stomach, use laser and heat treatments, and remove polyps. It is also possible to place feeding tubes into the stomach through the abdominal wall (PEG procedure).