Nerve
Glossopharyngeal nerve (CN IX)
Sensory, secretory and swallowing pathways of CN IX
High-yield
For the usual gag-reflex pathway, CN IX provides the sensory limb and CN X the motor limb. For parotid secretion, follow CN IX → tympanic plexus → lesser petrosal nerve → otic ganglion → auriculotemporal nerve.
Overview
CN IX links the medulla with the posterior tongue, pharynx, middle ear and carotid receptors. Its motor component supplies stylopharyngeus, and its parasympathetic component ultimately reaches the parotid gland. Rootlets emerge behind the olive above the vagal rootlets and travel through the jugular foramen. Sensory cell bodies occupy superior and inferior ganglia near this exit.
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Reference facts
- Origin
- Medullary connections: nucleus ambiguus for stylopharyngeus, inferior salivatory nucleus for parasympathetic output, solitary nucleus for taste and carotid afferents, and spinal trigeminal nucleus for general sensation. Rootlets emerge in the postolivary sulcus
- Skull exit
- Jugular foramen, generally anterior to the vagus and accessory nerves; superior and inferior sensory ganglia lie at or near the foramen
- Course
- Descends near the internal carotid artery and internal jugular vein, curves forward with stylopharyngeus and reaches the pharynx between the superior and middle constrictors. Branches reach the middle ear, carotid receptors, pharynx, tonsil and tongue
- Motor
- Stylopharyngeus elevates the pharynx during swallowing. Preganglionic secretomotor fibers reach the otic ganglion through the tympanic and lesser petrosal pathways; postganglionic fibers accompany auriculotemporal V3 to the parotid
- Sensory
- General sensation and taste from the posterior tongue, including vallate papillae; sensation from the oropharyngeal/tonsillar region and middle-ear–auditory-tube mucosa, including the inner tympanic surface. Carotid sinus and body afferents monitor pressure and blood chemistry
Clinical correlation
Glossopharyngeal neuralgia causes brief attacks of severe pain around the throat, tonsil, tongue base or ear, often triggered by swallowing. Occasionally, associated vagal reflex activity causes bradycardia or syncope. An absent gag reflex alone does not establish a CN IX lesion, because it can be absent in healthy people.
Frequently asked questions
Where does the glossopharyngeal nerve (CN IX) arise?
Medullary connections: nucleus ambiguus for stylopharyngeus, inferior salivatory nucleus for parasympathetic output, solitary nucleus for taste and carotid afferents, and spinal trigeminal nucleus for general sensation. Rootlets emerge in the postolivary sulcus.
What muscles does the glossopharyngeal nerve (CN IX) supply?
Stylopharyngeus elevates the pharynx during swallowing. Preganglionic secretomotor fibers reach the otic ganglion through the tympanic and lesser petrosal pathways; postganglionic fibers accompany auriculotemporal V3 to the parotid.
What is the sensory distribution of the glossopharyngeal nerve (CN IX)?
General sensation and taste from the posterior tongue, including vallate papillae; sensation from the oropharyngeal/tonsillar region and middle-ear–auditory-tube mucosa, including the inner tympanic surface. Carotid sinus and body afferents monitor pressure and blood chemistry.
Where does the glossopharyngeal nerve (CN IX) leave the skull?
Jugular foramen, generally anterior to the vagus and accessory nerves; superior and inferior sensory ganglia lie at or near the foramen.