Glossopharyngeal nerve

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Nerve: Glossopharyngeal nerve
Plan of upper portions of glossopharyngeal, vagus, and accessory nerves.
Course and distribution of the glossopharyngeal, vagus, and accessory nerves. (Label for glossopharyngeal is at upper right.)
Latin nervus glossopharyngeus
Gray's subject #204 906
Innervates stylopharyngeus
To tympanic nerve
MeSH A08.800.800.120.290
Dorlands/Elsevier 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

[edit] Functions

There are a number of functions of the glossopharyngeal nerve:

[edit] 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:

[edit] 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.

[edit] 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.

[edit] Additional images

[edit] External links

Cranial nerves

I-IV: olfactory - optic - oculomotor - trochlear

V: trigeminal: semilunar ganglion
V1: ophthalmic: lacrimal - frontal (supratrochlear, supraorbital) - nasociliary (long root of ciliary, long ciliary, infratrochlear, ethmoidal) - ciliary ganglion - short ciliary
V2: maxillary: middle meningeal - in the pterygopalatine fossa (zygomatic, zygomaticotemporal, zygomaticofacial, sphenopalatine, posterior superior alveolar)
in the infraorbital canal (middle superior alveolar, anterior superior alveolar)
on the face (inferior palpebral, external nasal, superior labial, infraorbital plexus) - pterygopalatine ganglion (deep petrosal, nerve of pterygoid canal)
branches of distribution (palatine, nasopalatine, pharyngeal)
V3: mandibular: nervus spinosus - internal pterygoid - anterior (masseteric, deep temporal, buccinator, external pterygoid)
posterior (auriculotemporal, lingual, inferior alveolar, mylohyoid, mental) - otic ganglion - submandibular ganglion

VI: abducent

VII: facial: nervus intermedius - geniculate - inside facial canal (great petrosal, nerve to the stapedius, chorda tympani)
at exit from stylomastoid foramen (posterior auricular, digastric - stylohyoid)
on face (temporal, zygomatic, buccal, mandibular, cervical)

VIII: vestibulocochlear: cochlear (striae medullares, lateral lemniscus) - vestibular

IX: glossopharyngeal: fasciculus solitarius - nucleus ambiguus - sympathetic efferent fibers - ganglia (superior, petrous) - tympanic

X: vagus: ganglia (jugular, nodose) - Alderman's nerve - in the neck (pharyngeal branch, superior laryngeal, recurrent laryngeal) - in the thorax (pulmonary branches, esophageal plexus) - in the abdomen (gastric plexuses, celiac plexus, gastric plexus)

XI: accessory XII: hypoglossal