Vocal cord positioning by selective denervation. Old territory revisited.
Vocal cord positioning produced by selective laryngeal denervation remains a controversial issue in clinical laryngology. Previous studies fail to arrive at uniform conclusions for two important reasons: 1) failure to mark a reference sagittal plane from which to assess the degree of vocal cord lateralization, and 2) failure to recognize the influence of tracheostomy and respiratory positioning of the vocal cords. The present study makes use of photographic and electromyographic documentation in the assessment of the paralyzed cord. Physiologic inactivation of the cricothyroid muscle by tracheostomy is a key determinant of the lateralized cord observed in acute low vagal and recurrent nerve paralysis. Tracheostomy-related cricothyroid inactivation cannot be ignored as a major determinant of cord positioning in paralysis and should not be overlooked in determining the neuroanatomic site of injury.
D000818:Animals; D003714:Denervation; D004285:Dogs; D007823:Laryngeal Nerves / Q000502:physiology; D012009:Recurrent Laryngeal Nerve / Q000502:physiology; D014140:Tracheotomy / Q000009:adverse effects; D014628:Vagotomy; D014826:Vocal Cord Paralysis / Q000209:etiology; D014827:Vocal Cords / Q000033:anatomy & histology*