http://digestive.niddk.nih.gov/ddiseases/pubs/sigmoidoscopy/index.htm
National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
Basic information about sigmoidoscopy -- a medical procedure that allows a physician to look at the inside of the large intestine to determine the cause of diarrhea, abdominal pain and constipation, or to look for early signs of cancer in the colon and rectum.