Endo-anal or endorectal ultrasound: A procedure in which an ultrasound transducer (probe) is inserted into the anus or rectum and used to. Shop South Park 1: Anal Probe / Volcano VHS at Best Buy. Find low everyday prices and buy online for delivery or in-store pick-up. Price Match Guarantee. An anoscopy is a simple medical procedure that can help your doctor identify an abnormality in your gastrointestinal tract, notable in your anus.