Laryngeal vibrations: measurements of the glottic wave. I. The normal vibratory cycle.

The student of laryngeal physiology encounters a wealth of diverse information on the subject of voice production: Different theories have been proclaimed and discussed heatedly by laryngeal scientists here and abroad, leaving the impression that many details are still nebulous and open to different interpretations. It is true that numerous important observations have been recorded on the activities of the external and internal laryngeal muscles during phonation, on the behavior of the mucous membrane covering the vocal cords, on the acoustic characteristics of the voice, and even on the sensations experienced during voice production with different laryngeal adjustments or "registers." Yet detailed quantitative measurements of the fundamental entity of voice production, the vibratory function of the vocal cords in human subjects, have had to await the development of special instruments and their adaptation for these studies. Whereas earlier investigators depended entirely upon anatomical preparations from animals and cadavers for their