sphinctero-, sphincter- +

(Greek > Latin: that which binds tightly, press together; band, lace; hence, muscle that closes an aperture of the body; a ringlike band of muscle fibers that constricts a passage or closes a natural orifice)

sphincterotome (s) (noun), sphincterotomes (pl)
An instrument for incising (cutting) a sphincter: Mr. Todd was told by Dr. Small that he would use a sphincterotome, an electrified wire, to perform the operation called sphincterotomy.
sphincterotomy (s) (noun), sphincterotomies (pl)
The surgical cutting of, or into a sphincter muscle; division of a sphincter: The surgical operation of sphincterotomy involves the treatment of fissures in the mucous membrane of the anal canal, of sphincter.

A cross reference of other word family units that are related directly, indirectly, or partially with: "opening, hole, cavity, tract, tube": alveolo-; antro-; anu-; celo-; coelio-; concho-; fenestra-; hernio-; hiat-; meato-; ora-; parieto-; poro-; pyl-, pyle-; pylor-; splanchn-; stomato-; syringo-; uretero-; urethro-; vagino-; ventricul-.