Abstract
The vocal fold vibration was basically studied using excised canine larynges and live canines. The vibratory pattern was observed and recorded by means of an X-ray stroboscope and an ultra-high speed camera. The frame by frame analysis of the motion pictures obtained revealed that only membranous part of the vocal fold vibrates while the muscle part does not move and the amplitude is the largest at the free edge. In addition, The trajectory of the movement was found almost circular only in the frontal plane. On the other hand, it was obseved to be almost linear in the superior and lateral planes.
The results mentioned above were obtained during the experimental phonation. Hereby, we newly designed a method by which we can obseve the wave motion even without vocalization. The wave motion can be induced extarnally by means of a vibrator.
Vibration (100/sec) was introduced into the larynx through the cervical skin and induced an external vibration on the vocal fold. Such a vibration was also analyzed and the same results as above mentioned was obtained. Observing the wave motion is very useful to estimate the physical property of the vocal fold. Even under general anesthesia, we perform surgical manipulations while estimating the stiffness of the vocal fold.
