The autonomic innervation in the pharynx. A study by the horseradish peroxidase tracer method.

Autonomic innervation of the mucosa in the pharynx was investigated by the horseradish peroxidase retrograde tracer method. The pharynx was divided into three regions, the epipharynx, mesopharynx, and hypopharynx. The epipharynx was sympathetically innervated by the fibers originating in the ipsilateral superior cervical ganglion and parasympathetically innervated by the fibers originating in the bilateral pterygopalatine ganglia. The mesopharynx and hypopharynx were sympathetically innervated by the fibers originating in the superior cervical, middle cervical, and stellate ganglia but not innervated by the pterygopalatine ganglion. The sympathetic innervation of the mesopharynx and hypopharynx was considered bilateral and predominant in the ipsilateral side. Comparing these two regions, the hypopharynx showed a tendency to be more innervated by the middle cervical and stellate ganglia.