Anatomy of the laryngeal sphincter. (a) The normal larynx provides a number of intrinsic and extrinsic mechanisms to protect the airway during the swallow. (b) Glottic tumors affect the main sphincter of the larynx, the vocal folds. (c) After a supracricoid laryngectomy with cricohyoidopexy most of the sphincters are lost (including the vocal folds and the epiglottis), and the airway is closed by displacement of the arytenoids against the tongue base. a: true vocal folds. b: false vocal folds. c: arytenoids. d: epiglottis. e: tongue base.