Lubrication mechanism of the larynx during phonation: An experiment in excised canine larynges

To evaluate how the viscosity of the laryngeal mucus influences vocal fold vibration, two fluids of differing viscosity were applied separately to exc ised canine larynges and experimental phonation was induced. Vibration of t he vocal folds was measured by use of a laryngostroboscope and an X-ray str oboscope. With the high viscosity fluid, the amplitude of vibration of the free edge and the peak glottal area was decreased while the open quotient w as increased. Because the viscosity of this fluid affected the wave motion of the vocal fold mucosa, changes in viscosity of the mucus may be involved in causing such disorders as hoarseness, in the absence of apparent change s in the vocal folds themselves.