AbstractComplete return of laryngeal function, as evidenced by normal excursion of the vocal folds during respiration and phonation, seldom follows division and repair of the laryngeal nerves. In order to investigate this phenomenon further the recurrent laryngeal nerve was sectioned and repaired in five dogs. Some functions of the intrinsic laryngeal muscles in these dogs were observed at intervals following repair of the nerve and compared to other dogs in which the nerve had been crushed or subjected to sustained pressure.Results obtained utilizing a high speed movie camera, electromyographic, and evoked electromyographic techniques, suggest that the reinnervated intrinsic laryngeal muscles showed impaired function when compared with normal muscles. The mechanisms possibly active in causing this reduction of function are discussed.