[Reorganization of the function of several intrinsic laryngeal muscles as a result of exclusion of one of them during respiration].

Electromyographic data on the effect of unilateral extirpation of the cricoarytenoid posterior muscle on other intrinsic muscles activity and on the vocal fold mobility were obtained in a series of chronic experiments in dogs,--before the extirpation, immediately after it, and in 1.5, 3, 6, and more months. The respiration was recorded simultaneously with the EMG of the intrinsic laryngeal muscles and with laryngoscopy and photography of the larynx. The data obtained showed a decrease in the electric activity of the lateral and vocal muscles on the side of the extirpated cricoarytenoid posterior muscle within 1.5-3 months after the operation, and traces of this activity sometimes not only in expiration as well. In about 6 months or more after the extirpation, the electric activity of the lateral and vocal muscles on the side of the extirpation occurred not in expiration, as before the operation, but in inspiration only. The vocal fold on this side of the larynx was in the paramedian position and immobile at the state of respiration during the whole period after the extirpation. The reconstruction of activity of the larynx sphincter muscles after extirpation of dilatatory muscles may be a result of the central reconstruction of coordination of some motoneurons connected with different muscles of the larynx and may have a compensatory character. This reconstruction occurring after the cricoarytenoid posterior muscle extirpation provides most favourable conditions for the respiratory function of the larynx.