The glossopharyngeal nerve (CN IX) originates in the medulla and exits the cranial cavity via the jugular foramen.  This nerve has numerous functions, including:

• Somatic motor:  Stylopharyngeus muscle only (elevates larynx during swallowing)

• Parasympathetic:  Inferior salivatory nucleus → CN IX → otic ganglion → travels along auriculotemporal nerve (CN V3) → parotid gland secretion

• General sensory:  Tympanic membrane (inner surface), eustachian tube, posterior third of tongue, tonsillar region, upper pharynx (afferent portion of gag reflex), carotid body, and carotid sinus

• Special sensory (taste):  Posterior third of tongue

Glossopharyngeal nerve lesions result in loss of general sensation in the upper pharynx, posterior tongue, tonsils, and middle ear cavity; loss of the gag reflex (afferent limb); and loss of taste sensation on the posterior third of the tongue.

(Choice A)  Protrusion of the tongue is mediated by motor efferent fibers carried by the hypoglossal nerve (CN XII).

(Choice B)  The muscles of the larynx are innervated predominantly by the vagus nerve (CN X) and its branches (particularly the recurrent laryngeal nerve).

(Choice C)  Taste sensation from the anterior two-thirds of the tongue is mediated by the chorda tympani branch of the facial nerve (CN VII).

(Choice E)  Salivary secretion from the submandibular and sublingual glands is mediated by parasympathetic fibers originating in the superior salivatory nucleus carried on the facial nerve (CN VII) via the chorda tympani and lingual nerves across the submandibular ganglion.

Educational objective:
Lesions of the glossopharyngeal nerve result in loss of the gag reflex (afferent limb); loss of sensation in the upper pharynx, posterior tongue, tonsils, and middle ear cavity; and loss of taste sensation on the posterior third of the tongue.