Abstract
Twenty four cases of unilateral laryngeal paralysis were examined by contrast laryngography. The characteristic feature of the laryngeal paralysis in these contrast laryngogram was that the vocal fold on the affected side was fixed in the half adducted position during respiration. This corresponded to the laryngoscopic view of the vocal fold fixed at the intermediate position. During phonation, the larynx was seen to be elevated, and the shape of the laryngeal cavity changed. However, the tracheal portion of the vocal tract did not change on the contrast laryngogram. When the contrast laryngograms taken during respiration and phonation were superimposed at the unchanging tracheal portion, the movement of the vocal folds could be measured and quantified. The vocal fold on the affected side was slightly adducted during phonation in 10 out of the 24 cases of unilateral paralysis, and abducted in 2 cases (paradoxical movement due to misdirected regeneration of the recurrent laryngeal nerve) and fixed in the rest 12 cases. The position of the vocal fold on the affected side during phonation was related to its mobility. When it was slightly adducted, it seemed to be fixed at the paramedian position in the laryngoscopic examination. When it was not adducted, it was fixed at the intermediate position.
