Sensory nerve supply of the human oro- and laryngopharynx: A preliminary study

To date, the details of human sensory innervation to the pharynx and upper airway have not been demonstrated. In this study, a single human oro- and l aryngopharynx obtained from autopsy was processed with a whole-mount nerve staining technique, Sihler's stain, to determine its entire sensory nerve s upply. The Sihler's stain rendered all mucosa and soft tissue translucent w hile counterstaining nerves. The stained specimen was then dissected and th e nerves were traced from their origins to the terminal branches. It was fo und that the sensory innervation of the human pharynx is organized into dis crete primary branches that innervate specific areas, although these areas are often connected by small neural anastomoses. The density of innervation varied, with some areas receiving almost no identifiable nerve supply (e.g ., posterior wall of the hypopharynx) and certain areas contained much high er density of sensory nerves: the posterior tonsillar pillars; the laryngea l surface of the epiglottis; and the postericoid and arytenoid regions. The posterior tonsillar pillar was innervated by a dense plexus formed by the pharyngeal branches of the IX and X nerves. The epiglottis was densely inne rvated by the internal superior laryngeal nerve (ISLN) and IX nerve. Finall y, the arytenoid and postericoid regions were innervated by the ISLN. The p ostericoid region had higher density of innervation than the arytenoid area . The use of the Sihler's stain allowed the entire sensory nerve supply of the pharyngeal areas in a human to be demonstrated for the first time. The areas of dense sensory innervation are the same areas that are known to be the most sensitive for triggering reflex swallowing or glottic protection. The data would be useful for further understanding swallowing reflex and gu iding sensory reinnervation of the pharynx to treat neurogenic dysphagia an d aspiration disorders. Anat Rec 258:406-420, 2000. (C) 2000 Wiley-Liss, In c.