Glossopharyngeal Nerve Anatomy
1. Geniculate ganglion of facial nerve
2. Greater petrosal nerve
3. Deep petrosal nerve
4. Lesser petrosal nerve
5. Otic ganglion
6. Auriculotemporal nerve (CN V3)
7. Parotid gland
8. Stylopharyngeus muscle and nerve branch from
CN IX
9. Pharyngeal plexus
10. Carotid branch of CN IX
11. Superior cervical ganglion
12. Vagus nerve
13. Jugular foramen
14. Glossopharyngeal nerve
15. Inferior salivatory nucleus
Comment: The glossopharyngeal nerve innervates only 1 muscle
(stylopharyngeus) but receives significant general sensory distribution from
the pharynx, posterior third of the tongue, middle ear, and auditory tube. CN
IX is the nerve of the 3rd pharyngeal (branchial) embryonic arch.
The special sense of taste (posterior
third of the tongue) also is conveyed by this nerve. Cardiovascular sensory
fibers include those associated with the carotid body (chemoreceptor) and
carotid sinus (baroreceptor) region adjacent to the common carotid artery bifurcation.
Clinical: Placing a tongue depressor on the posterior third of
the tongue elicits a gag reflex, mediated by the sensory fibers of CN IX on the
posterior third of the tongue, which then triggers a gag and elevation of the
soft palate, mediated largely by the vagus nerve (CN
X).
