Sphincter

sfingk′tėr, n. ( an at. ) a muscle that contracts or shuts an orifice or opening which it surrounds—around the anus, .— adjs. Sphinc′terāte , provided with a sphincter, contracted as if by a sphincter; Sphinctē′rial , Sphincter′ic , relating to a sphincter or its function.— n. Sphincterot′omy , the operation of cutting a sphincter. [Gr. sphingktēr ,— sphinggein , to bind tight.]