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Glossopharyngeal nerve

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Plan of upper portions of glossopharyngeal, vagus, and accessory nerves. |- style="text-align: center;" class="hiddenStructure" | colspan="2" |
|- style="text-align: center; line-height: 1;" class="hiddenStructure" | colspan="2" |Course and distribution of the glossopharyngeal, vagus, and accessory nerves. (Label for glossopharyngeal is at upper right.) |- class="hiddenStructure" |Latin |colspan="2"|nervus glossopharyngeus |- class="hiddenStructure" | |colspan="2"|[subject #204 ] |- class="hiddenStructure" |Innervates |colspan="2"|stylopharyngeus |- class="hiddenStructure" |From |colspan="2"| |- class="hiddenStructure" |To |colspan="2"|tympanic nerve |- class="hiddenStructure" |MeSH |colspan="2"|[A08.800.800.120.290] |- class="hiddenStructure" |Dorlands/Elsevier |colspan="2"|[n_05/12565844] |} The glossopharyngeal nerve is the ninth of twelve cranial nerves. It exits the brainstem out from the sides of the upper medulla, just rostral (closer to the nose) to the vagus nerve.

Contents

1 Functions
2 Brainstem connections
3 Path
4 Testing the glossopharyngeal nerve
5 External links

Functions
There are a number of functions of the glossopharyngeal nerve:

It receives sensory fibres from the posterior one-third of the tongue, the tonsils, the pharynx, the middle ear and the carotid body.
It supplies parasympathetic fibres to the parotid gland via the otic ganglion.
It also supplies motor fibres to stylopharyngeus muscle and the upper pharyngeal muscles.
Brainstem connections
The glossopharyngeal nerve, being mostly sensory, does not have a cranial nerve nucleus of its own. Instead it must project into many different structures in the brainstem:

Solitary nucleus: Taste from the posterior one-third of the tongue and information from carotid baroreceptors and carotid body chemoreceptors
Spinal nucleus of the trigeminal nerve: Visceral pain as well as somatic sensory fibers from the skin of the outer ear.
Nucleus ambiguus: The lower motor neurons for the stylopharyngeus muscle.
Inferior salivatory nucleus: Parasympathetic input to the parotid and mucous glands.
Path
From the medulla oblongata, the glossopharyngeal nerve passes laterally across the flocculus, and leaves the skull through the central part of the jugular foramen, in a separate sheath of the dura mater, lateral to and in front of the vagus and accessory nerves.
In its passage through the jugular foramen, it grooves the lower border of the petrous part of the temporal bone; and, at its exit from the skull, passes forward between the internal jugular vein and internal carotid artery; it descends in front of the latter vessel, and beneath the styloid process and the muscles connected with it, to the lower border of the Stylopharyngeus.
It then curves forward, forming an arch on the side of the neck and lying upon the Stylopharyngeus and Constrictor pharyngis medius.
Thence it passes under cover of the Hyoglossus, and is finally distributed to the palatine tonsil, the mucous membrane of the fauces and base of the tongue, and the mucous glands of the mouth.

Testing the glossopharyngeal nerve
The gag reflex is absent in patients with damage to the glossopharyngeal nerve as it is responsible for the afferent limb of the reflex.

External links
NeuroNames [hier-698]
[Loyola]
MedlinePlus Image [9350]
Nerve: Glossopharyngeal nerve

Major nerves (also see Peripheral nervous system)
Cranial nerves: I olfactory | II optic | III oculomotor | IV trochlear | V trigeminal | V1 ophthalmic (lacrimal, frontal, supratrochlear, supraorbital, nasociliary, ciliary ganglion) | V2 maxillary (sphenopalatine ganglion) | V3 mandibular (buccal - auriculotemporal - lingual - inferior alveolar - otic ganglion) | VI abducens | VII facial (chorda tympani, nervus intermedius) | VIII vestibulocochlear (cochlear, vestibular) | IX glossopharyngeal | X vagus (recurrent laryngeal, Alderman's nerve) | XI accessory | XII hypoglossal
Posterior spinal nerves: greater occipital
C1-C4 - Cervical plexus: lesser occipital | greater auricular | lesser auricular | phrenic | ansa cervicalis
C5-C8, T1 - Brachial plexus: supraclavicular branches (dorsal scapular, suprascapular, long thoracic) | lateral cord (musculocutaneous, lateral antibrachial cutaneous, lateral head of median nerve) | medial cord (ulnar, medial head of median nerve, medial antibrachial cutaneous, medial brachial cutaneous) | posterior cord (axillary, radial)
T2-T11: intercostal
T12, L1-L5 - Lumbar plexus: iliohypogastric | ilioinguinal | genitofemoral | lateral femoral cutaneous | femoral | obturator
S1-S4 - Sacral plexus: gluteal | posterior femoral cutaneous | tibial | sciatic | sural | common peroneal
S2-S5 - Pudendal plexus: perforating cutaneous | pudendal | visceral | muscular | anococcygeal

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