Changes in vocal fold length with nerve stimulation in canine larynges

Abstract

Vocal fold length change and adductory movement of the glottis were obtained from seven canine larynges when the recurrent and the superior laryngeal nerve were stimulated bilaterally. A surgical procedure was used to make marks on the vocal fold for length measurements. Frame by frame analysis was used to get static and dynamic data on vocal fold length. The mean maximum elongation of the membranous vocal folds was 44.7% with 120‐ms elongation time and 140‐ms relaxation time. The mean maximum shortening of membranous vocal folds was 17.8%, with 110‐ms contraction time and 115‐ms relaxation time. When both agonist and antagonist muscles were in maximum contraction, the mean elongation was 24.3%. The length‐time curve approximates an exponential function. Closing of glottis occurred in less than 35 ms. The temporal results agree with earlier pitch change results. [Work supported by NIH Grant NS16320.]