one of the contractile organs of the body

a sphincter that is not recognizable at autopsy because its resting arrangement cannot be distinguished from adjacent tissue

the sphincter muscle of the anus

a striated sphincter muscle that constricts the urethra

the sphincter muscle of the urinary bladder; made up of a thickened muscular layer of bladder around the urethral opening

the smooth muscle sphincter of the common bile duct