Glossopharyngeal nerve (CN IX)
Nerve · CN IX Mixed Parasympathetic
Leaves the lateral medulla behind the olive and exits the skull through the jugular foramen with X and XI, then passes between the internal carotid artery and internal jugular vein to the tongue and pharynx. Mixed: taste and general sensation from the posterior third of the tongue and oropharynx, sensation from the middle ear and carotid sinus and body, motor to stylopharyngeus alone, and parasympathetic supply to the parotid.
Traced from the start
- Medulla oblongata
- Glossopharyngeal nerve (CN IX)
Detail
- Sensory
- Posterior third of tongue (taste and general sensation), oropharynx and tonsil, middle ear and Eustachian tube (tympanic branch), carotid sinus baroreceptors and carotid body chemoreceptors (carotid sinus nerve)
- Motor
- Stylopharyngeus only (elevates the pharynx in swallowing)
- Parasympathetic
- Inferior salivatory nucleus → tympanic nerve → lesser petrosal nerve (through the foramen ovale) → otic ganglion → auriculotemporal nerve of V3 → parotid gland
- Reflex
- Afferent limb of the gag reflex (efferent X); afferent limb of the carotid sinus baroreflex
When it goes wrong
Jugular foramen lesion involving IX (almost never an isolated palsy)
Loss of the gag reflex afferent and of taste and sensation on the posterior third of the tongue on that side, with the accompanying X and XI signs
Glossopharyngeal neuralgia from vascular compression of the root
Paroxysms of severe stabbing pain in the throat, tonsil and deep ear triggered by swallowing or coughing; the afferent barrage can provoke bradycardia and syncope through the carotid sinus reflex
Tonsillitis, peritonsillar abscess or carcinoma of the tongue base or tonsil stimulating IX
Referred otalgia via the tympanic branch with a normal ear examination; persistent unexplained ear pain in a smoker needs the oropharynx examined
Practise this structure
4 questions in the bank tagged Cranial Nerves.
A 52-year-old woman has had two months of numbness over the right forehead, the right upper eyelid and the tip of her nose, with a gritty feeling in the right e…
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A 44-year-old man has had 18 months of worsening hearing on the left with constant ringing in that ear. He still follows conversation in a quiet room but cannot…
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A 58-year-old man has sudden vertigo and a hoarse voice, and chokes when he drinks. The palate elevates to the right and there is no gag response when the left…
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A 27-year-old man was struck on the head at football a week ago. He now sees two images, one above the other, worst when reading or going down stairs. The verti…
Foundations · middle twist