Taste sensation on the posterior one-third of the tongue is mediated by which cranial nerve?

Taste sensation on the posterior one-third of the tongue is mediated by which cranial nerve?

• A. Cranial Nerve VII (CN VII)
• B. Cranial Nerve X (CN X)
• C. Cranial Nerve IX (CN IX)
• D. Cranial Nerve II (CN II)

Answer: (C)

Taste from the posterior one-third of the tongue is carried by the glossopharyngeal nerve. Its gustatory fibers innervate the back of the tongue and send information to the nucleus of the solitary tract, then up to the thalamus and gustatory cortex. The anterior two-thirds obtain taste via the chorda tympani branch of the facial nerve, while the vagus carries taste from areas like the epiglottis, not the posterior tongue. The optic nerve has no role in taste. Thus, the posterior tongue’s taste is mediated by the glossopharyngeal nerve.

Taste from the posterior one-third of the tongue is carried by the glossopharyngeal nerve. Its gustatory fibers innervate the back of the tongue and send information to the nucleus of the solitary tract, then up to the thalamus and gustatory cortex. The anterior two-thirds obtain taste via the chorda tympani branch of the facial nerve, while the vagus carries taste from areas like the epiglottis, not the posterior tongue. The optic nerve has no role in taste. Thus, the posterior tongue’s taste is mediated by the glossopharyngeal nerve.