Sensory innervation of the pharynx and larynx

To shed light on supraesophageal complications of reflux disease, sensory innervation--particularly, distinct distribution, area, and density of sensory fibers--of the feline pharyngolaryngeal mucosa was reported. The investigations were performed by means of histochemistry (tracer techniques) and immunohistochemistry. The pharyngeal mucosa from the Eustachian cushion to the middle level of aryepiglottic fold, except the laryngeal surface of epiglottis, was supplied by the glossopharyngeal sensory fibers, whereas the laryngeal sensory fibers innervated between the apex of epiglottis and the level of the first tracheal ring in the larynx and between the middle level of aryepiglottic fold and the caudal end of piriform sinus in the pharynx. Most areas of the mucosa, except the subglottis, had unilateral innervation. The subglottis, including the caudal aspect of vocal fold and the posterior glottis, had bilateral supply with ipsilateral predominance. The density of sensory fibers in the vestibule of larynx involving the posterolateral aspect of arytenoid eminence was much heavier than the other parts. Sensory nerve fibers around the caudal pole of palatine tonsil, and in the root of tongue and the hypopharyngeal wall also were dense. Regional distribution and density of substance P and calcitonin gene-related peptide immunoreactive fibers showed almost the same pattern as did the sensory fibers.