Which cranial nerve provides tongue and throat motor and sensory, with taste on the posterior third?

• A. Vagus
• B. Hypoglossal
• C. Accessory
• D. Glossopharyngeal

Answer: (D)

Taste from the posterior third of the tongue comes from a nerve that also handles sensation from the throat region and provides motor to a pharyngeal muscle involved in swallowing. This nerve is mixed: it carries taste (special visceral afferent) from the posterior tongue, general sensation from that area and the oropharynx (somatic afferent), and motor fibers to the stylopharyngeus muscle (branchial motor), which helps elevate the pharynx during swallowing. It also carries parasympathetic to the parotid gland.

That combination fits glossopharyngeal function: it supplies the posterior tongue with taste and sensation and contributes to throat motor activity via stylopharyngeus. The other nerves don’t match this profile: the vagus mainly handles pharyngeal and laryngeal muscles and sensation/taste in other regions, not the posterior tongue; the hypoglossal is purely tongue motor; the accessory is not involved with tongue sensation or swallowing.