The stylopharyngeus is the only muscle in the head supplied exclusively by the glossopharyngeal nerve, making it both a clinical test of CN IX motor function and a surgical landmark for identifying CN IX during neck procedures. It passes between the external and internal carotid arteries, where it is found by the surgeon as the landmark for the superior laryngeal nerve and CN IX.
| Origin | Root of the medial surface of the styloid process |
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| Insertion | Blends with the middle and inferior pharyngeal constrictors at the posterior border of the thyroid cartilage |
| Nerve Supply | Glossopharyngeal nerve (CN IX) — the only muscle in the head supplied exclusively by CN IX |
| Blood Supply | Ascending pharyngeal artery |
| Actions | Elevates and dilates the pharynx during swallowing; Elevates the larynx; Opens the pharynx to receive the food bolus from the oropharynx |
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It is the primary dilator of the pharynx during swallowing, widening and elevating the pharyngeal tube to receive the bolus propelled by the tongue. Without this dilation, the constrictors would have no space to propel the bolus into.
Stylopharyngeus is the motor test for CN IX function — assessing pharyngeal elevation during swallowing and the gag reflex afferent pathway alongside the soft palate elevation for CN X. In glossopharyngeal neuralgia surgery, the stylopharyngeus is the landmark that the surgeon uses to identify the CN IX nerve trunk as it emerges between the external and internal carotid arteries.
Not externally palpable. Motor function assessed by watching pharyngeal elevation symmetry during swallowing, and afferent function by the gag reflex.
CN IX injury producing stylopharyngeus weakness with impaired pharyngeal dilation and swallowing difficulty, usually occurring alongside vagal palsy in jugular foramen syndrome.
