What are the main functions of the glossopharyngeal nerve (CN IX)?

The glossopharyngeal nerve has mixed sensory and motor functions. Key roles include sensory functions like taste from the posterior tongue and general sensation from the pharynx, tonsils, and soft palate, and motor functions such as innervation of the stylopharyngeus muscle and parasympathetic control of the parotid gland.

How does the glossopharyngeal nerve exit the skull?

It exits the skull through the jugular foramen, along with the vagus and accessory nerves (CN X and XI). The nerve is enclosed in dura and has sensory ganglia located near this foramen.

What are the key branches of the glossopharyngeal nerve and what do they innervate?

Major branches include the tympanic branch for parasympathetic innervation of the parotid gland, the carotid branch for carotid sinus and body reflexes, and pharyngeal, tonsillar, and lingual branches for sensory and motor functions in the throat and tongue.

What clinical symptoms occur with a glossopharyngeal nerve lesion?

Symptoms include loss of taste and sensation in the posterior tongue, difficulty swallowing, reduced saliva from the parotid gland, and a unilateral loss of the gag reflex. These are rare in isolation.

How is the glossopharyngeal nerve tested clinically?

Testing involves eliciting the gag reflex by touching the posterior pharyngeal wall and assessing taste on the posterior one-third of the tongue. This helps evaluate its sensory and motor functions.

What is glossopharyngeal neuralgia?

It is a rare pain syndrome characterized by severe, paroxysmal pain in the throat, tongue, or ear, often triggered by swallowing. This results from irritation in the sensory distribution of CN IX.

What structures does the glossopharyngeal nerve pass near in the neck?

After exiting the skull, it courses between the internal carotid artery and internal jugular vein, then passes deep to the external carotid artery to reach the stylopharyngeus muscle and pharynx.

Glossopharyngeal Nerve (CN IX) – Functions & Clinical

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