Infratemporal Fossa - LO 7

7. What nerve fibers relay taste (special sensory) and general sensory information from the tongue to the brain?

Afferently, the tongue has both general somatic and special visceral (taste) afferent innervations. An important landmark for the afferent innervation of the tongue are the vallate papilla (not the terminal sulci). In terms of somatic afferents:

• • areas anterior to the vallate papillae are innervated by the lingual n. (V3), whereas

  • areas posterior to the vallate papillae are innervated by the glossopharyngeal n.

There is a slight overlap of somatic afferent innervation in the posteromedial root of the tongue, which is innervated by both the glossopharyngeal n. and vagus n (via the internal br. of the superior laryngeal n.). The vallate papillae also demarcate the two sources of special visceral afferent (taste) serving the taste buds:

• • anterior to the vallate papillae, taste is modulated via the facial n. (chorda tympani ← lingual n.), whereas

  • posterior to the vallate papillae, taste is modulated via the glossopharyngeal n.