Observation on nerve endings in human intrinsic laryngeal muscles by using silver impregnation method.

Stereographic structures of nerve endings in the human posterior cricoarytenoid muscle were clearly demonstrated by means of the silver impregnation method developed by Barker under a light microscope. Three types of motor nerve endings (en plaque, en ligne and en grappe) and their transitional forms were found. Moreover, multimotor end-plates on the single muscle fiber were discovered. Accessory end-plates which were assumed to be autonomic fibers also existed. Three types of sensory nerve endings (i. e., simple terminal loops, spiral nerve endings and flowerlike endings) were identified on the surface of a muscle fiber. It is concluded that the nerve ending in the human posterior cricoarytenoid muscle is multi-modal.