Which nerve mediates taste from the anterior two-thirds of the tongue?

• A. Glossopharyngeal nerve (CN IX)
• B. Facial nerve (CN VII) via the chorda tympani
• C. Vagus nerve (CN X)
• D. Trigeminal nerve (CN V)

Answer: (B)

Taste from the front two-thirds of the tongue is carried by special visceral afferent fibers that travel with a branch of the facial nerve called the chorda tympani. These taste fibers originate in the taste buds there, have their cell bodies in the geniculate ganglion, and join the lingual nerve (a branch of V3) to reach the tongue. Central fibers go to the solitary nucleus in the brainstem before reaching the gustatory cortex. This pathway explains why the chorda tympani, a branch of the facial nerve, mediates taste from that region. The glossopharyngeal nerve handles taste from the posterior third; the vagus handles taste in other areas like the epiglottis; and the trigeminal nerve provides general sensory information from the tongue, not taste.