The role of the cricothyroid muscle in tension of the vocal cords; an experimental study in dogs designed to release tension of the vocal cords in bilateral recurrent laryngeal nerve paralysis.

Abstract

A study of bilateral recurrent laryngeal nerve paralysis in dogs was undertaken for the purpose of finding a way of altering the muscular control of the vocal cords so as to release either or both of them from the adducted position and so avoid the need for a permanent tracheotomy tube. Study of the muscular control of the larynx suggested that a more satisfactory solution of the problem than removal of the arytenoid and changing the position of a cord, as is done in the King, Kelly, and Woodman¹operations, should be possible (Fig. 1). Semon's Law^*states that in bilateral laryngeal nerve paralysis adduction prevails longer than abduction because the posterior cricoarytenoid muscle, which controls the latter position, fails first. Murtagh and Campbell † lent support to this law by observing in animal experiments that the fibers of the adductor muscles were greater in size and number than