sphincteroscope

sphinc·ter·o·scope

(sfingk'tĕr-ō-skōp'),
A speculum to facilitate inspection of the internal sphincter ani muscle.
[sphincter + G. skopeō, to view]

sphincteroscope

(sfĭngk′tĕr-ō-skōp″) [″ + skopein, to examine]
An instrument for inspection of the anal sphincter.