Examination of the inner lining (mucosa) of the most distal large intestine (colon), corresponding to the sigmoid, rectum and anus; By means of an optical device (like a small camera) located in a flexible tubular element called videogioscope which is passed through the anus.

The patient must completely remove his clothes to expose the lower part of the body. The person should lie on the left side with the knees bent towards the chest.