Glossopharyngeal nerve (CN IX)
After working through this study unit you will be able to:
- Describe the structure, course and relations of the glossopharyngeal nerve.
- Name the associated nuclei of the glossopharyngeal nerve.
- List the branches and functions of the glossopharyngeal nerve.
The glossopharyngeal nerve (CN IX) is a mixed cranial nerve that carries both motor and sensory fibers. Its functions include:
- general somatic afferent (GSA) innervation of the tongue and throat
- special visceral afferent (SVA) sensation of taste to the posterior third of the tongue
- general visceral afferent (GVA) sensation from specific structures of the common carotid artery (carotid sinus and carotid body)
- general somatic efferent (GSE) innervation is also provided to the stylopharyngeus muscle
- general visceral efferent (GVE) secretomotor (parasympathetic) innervation to the parotid gland
The glossopharyngeal nerve has four nuclei which are located in the medulla. Motor fibers of the nerve originate from the nucleus ambiguus and inferior salivatory nucleus, while the sensory fibers of the nerve originate in the sensory nuclei of the trigeminal nerve (CN V) and nuclei of the solitary tract. The glossopharyngeal nerve emerges from the lateral region of the medulla and exits the cranial cavity through the jugular foramen. After exiting the cranium, the nerve gives rise to the tympanic, carotid, pharyngeal, muscular, tonsillar and lingual branches that supply several structures in the head and neck.
This video will help you learn more about the glossopharyngeal nerve.
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Take a look at our atlas gallery to further review the course, distribution and supply of the glossopharyngeal nerve in more detail.
Fiber types: General somatic efferent (GSE), special visceral afferent (SVA), general somatic afferent (GSA), general visceral afferent (GVA), general visceral efferent (GVE)
Origin: Medulla oblongata
Exists skull: Jugular foramen
Motor: Nucleus ambiguus (SVE) and inferior salivatory nucleus (GVE)
Sensory: Nucleus of trigeminal nerve (GSA) and nuclei of solitary tract (SVA)
Sensory: Superior and inferior ganglia of glossopharyngeal nerve
Parasympathetic: Otic ganglion
Motor innervation: Stylopharyngeus muscle
Taste innervation: Posterior third of tongue
General sensation: Tympanic cavity, eustachian tube, fauces, tonsils, nasopharynx, uvula and posterior third of tongue
Visceral sensation: Carotid body and sinus
Parasympathetic innervation: Parotid gland