Morphological Features of the Glossopharyngeal Nerve in the Peripharyngeal Space, the Oropharynx, and the Tongue.

The glossopharyngeal nerve comprises sensory, motor and parasympathetic fibers, and its problem results in several disorders. This study investigated the glossopharyngeal nerve to elucidate the characteristics of its extracranial course and branching pattern. The nerve and adjacent structures were gross anatomically examined in 32 cadavers. The glossopharyngeal nerve descended from the jugular foramen in the peripharyngeal space. It dodged between the carotid arteries and the internal jugular vein and distributed the carotid and pharyngeal branches that formed the plexus with the branches of the vagus and sympathetic nerves. The glossopharyngeal nerve curved anteriorly around the stylopharyngeus and supplied it and the glossopharyngeus. However, it occasionally disappeared because it penetrated the stylopharyngeus. The nerve passed medially to the stylohyoid ligament to enter the oropharynx, with its entry located medially to the facial artery. It appeared anteriorly to the stylopharyngeus and the palatopharyngeus and inferiorly to the palatine tonsil in the oropharynx. Its appearance was obscured beneath the tonsil and, sometimes, beneath the longitudinal muscles. The nerve distributed the branches to the palatine tonsil, which formed a plexus with those that pierced the glossopharyngeus from the outside. At the root of the tongue, the nerve ramified into the posterior branches to the epiglottic vallecula, the medial ones the lingual tonsil and the vallate papillae and the anterior ones the vallate and foliate papillae. This study suggests that, occasionally, the detection of the glossopharyngeal nerve is challenging, and its association with the pharyngeal muscles and the facial artery can facilitate its localization. Anat Rec, 302:630-638, 2019.