Motor innervation of the human cricopharyngeus muscle

Innervation of the human cricopharyngeus muscle remains historically contro versial and unclear, encouraging numerous treatments inconsistently designe d to pharmacologically or mechanically alter the contractile state of this muscle. Neuroanatomic controversy results from and is perpetuated by 1) use of nonhuman models, 2) observational misinterpretation ol: small-diameter, overlapping nerve fibers, and, most importantly, 3) lack of real-time veri fication of neural projections. We sought to overcome these difficulties by performing microdissections in 27 patients undergoing laryngectomy and usi ng teal-time electromyographic verification. We demonstrated 1) dual ipsila teral innervation by the pharyngeal plexus and recurrent laryngeal nerve, 2 ) segmental projection of the recurrent laryngeal nerve to anterior motor u nits, 3) pharyngeal plexus projection to posterior motor units, 4) absence of a sympathetic or external superior laryngeal nerve contribution, and 5) absence of contralateral innervation. Such dual ipsilateral innervation, se gmentally projected, has not been previously described in any other form of neuromuscular organization. Neuroanatomic accuracy should improve diagnost ic and therapeutic strategies for future management of pharyngeal dysphagia .