n.
Lighted tube used to inspect the rectum and lower colon .
It is 10 in. (25 cm) long, allowing the entire rectal lining to be examined for evidence of disease. It is inserted into the anal canal and advanced as far as is comfortable for the patient. Modern fibre-optic proctoscopes allow more extensive observation with less discomfort. Proctoscopy is standard in physical examinations of older persons. See also endoscopy .