Abstract
It is indicated in the contrast laryngogram that the larynx and trachea are moved upward during phonation and the shape of the laryngeal cavity is changed, but that of the trachea is not changed during respiration and phonation. When both laryngrams during phonation and respiration are superimposed at the portion of the trachea, the change of the laryngeal cavity, that is, the movement of the vocal and false cords can be quantitatively observed. Twenty six cases of unilateral recurrent laryngeal nerve paralysis and 4 cases of bilateral paralysis were examined by contrast laryngography. It was found that the vocal cord on diseased side is slightly adducted during phonation in 11 cases of unilateral paralysis and is abducted (paradoxical movement) in 2 cases. In 4 cases of bilateral paralysis the vocal cord was noticed to be adducted in six sides.
These findings correspond to the electromyographical observation that some electrical activities of laryngeal muscles on the paralysed side are recorded in many cases of the recurrent laryngeal nerve paralysis.
