A sigmoidoscopy is a diagnostic procedure that allows the doctor to examine the lower one-third of the large intestine. Sigmoidoscopy is helpful in identifying the causes of diarrhea, abdominal pain, constipation, abnormal growths, and bleeding. It may also be used to obtain biopsies and to perform procedures, such as removal of polyps or hemorrhoids. Sigmoidoscopy is also used to screen for colorectal cancer, the second leading cause of cancer deaths in the U.S.
A short, flexible, lighted tube, called a sigmoidoscope, is inserted into the intestine through the rectum into the lower part of the large intestine. Air is injected into the intestine through the sigmoidoscope to inflate it for better viewing.
A sigmoidoscopy may be used to visualize or diagnose colon polyps, tumors, ulceration, inflammation, hemorrhoids, diverticula (pouches), and strictures (narrowing) in the sigmoid colon. It may also be used to determine the cause of recent changes in bowel habits, lower abdominal pain, itching around the anus, or the passage of blood or mucus in the stool.