You are positioned on your left side with your knees drawn up toward your chest. This is called a digital rectal examination. Following the digital rectal exam, the sigmoidoscope will be inserted. This is a flexible fiberoptic tube about 20 inches long. The scope is gently advanced into the colon.
Air is introduced into the scope to aid in viewing.
The air may cause the urge to defecate. As the sigmoidoscope is slowly removed, the lining of the bowel is carefully examined. A channel in the scope allows for the passage of forceps for biopsies or other instruments for therapy. How to prepare for the test You must sign an informed consent form. You will wear a hospital gown.