Tongue Anatomy: Muscles, Mucosa, Papillae, Innervation, and Taste

Muscular Structure

• Intrinsic muscles (superior/inferior longitudinal, transverse, vertical) – alter shape (shorten, curl, narrow).
• Extrinsic muscles (genioglossus, hyoglossus, styloglossus, palatoglossus) – change position (protrude, retract, elevate, depress).
• All innervated by hypoglossal nerve (CN XII) except palatoglossus (vagus, CN X).

Mucosa and Papillae

Papilla Type	Location	Structure	Taste Buds
Filiform	Anterior 2/3 dorsum	Conical, keratinized; no taste buds	None (mechanical)
Fungiform	Tip and sides	Mushroom-shaped, vascular	Yes (CN VII via chorda tympani)
Circumvallate	Circumvallate line (V-shaped)	Large, circular, moat	Yes (CN IX)
Foliate	Posterior lateral edges	Vertical folds	Yes (CN IX)

Innervation

• Motor: CN XII (all intrinsic + extrinsic except palatoglossus).
• Taste (special sensory):
  • Anterior 2/3: CN VII (chorda tympani → lingual nerve).
  • Posterior 1/3: CN IX (glossopharyngeal).
  • Epiglottis/epipharynx: CN X (vagus).
• General sensation: CN V3 (lingual nerve) anterior 2/3; CN IX posterior 1/3; CN X base.

Vasculature

• Lingual artery (branch of external carotid) → dorsal lingual, deep lingual, sublingual branches.
• Venous drainage → internal jugular via lingual vein.

Lingual Frenulum

Mucosal fold connecting ventral tongue to floor of mouth; limits anterior protrusion. Ankyloglossia (tongue-tie) if short/thick → feeding/speech issues.