Tongue: anatomy, functions, sensation and clinical overview

Surface, papillae and taste

The dorsal surface of the tongue is characterized by papillae of several types. Filiform papillae are numerous and provide friction but do not contain taste buds. Fungiform, foliate and circumvallate papillae contain taste receptors commonly called taste buds. Taste perception arises from chemoreceptors that detect basic qualities such as sweet, salty, sour, bitter and umami; the older idea of a strict "taste map" on the tongue is inaccurate, because taste receptors are distributed across the surface. For introductory material on taste and sensation see taste and sensation and more on receptor distribution at taste bud information.

Anatomy and supporting tissues

Intrinsic muscles (superior and inferior longitudinal, transverse and vertical) change the tongue's shape. Major extrinsic muscles include the genioglossus, hyoglossus, styloglossus and palatoglossus, which anchor the tongue to surrounding bones and soft tissues. The mucosa over the base of the tongue includes lymphoid tissue (lingual tonsil) that contributes to immune defense.

Innervation and blood supply

Sensory and motor innervation involve several cranial nerves. General sensation from the anterior two-thirds is carried by the lingual nerve (branch of the mandibular nerve), while taste from that region is carried by the chorda tympani (a branch of the facial nerve). The posterior third receives both taste and general sensation via the glossopharyngeal nerve. Motor control of most tongue muscles is by the hypoglossal nerve, with the palatoglossus muscle supplied by the vagus nerve. The main arterial supply is from branches of the lingual artery; venous drainage follows lingual veins toward the internal jugular system.

Functions

• Taste: Chemical sensing that informs food choice and safety.
• Mastication and bolus formation: Positioning, mixing with saliva and shaping of food for swallowing.
• Deglutition (swallowing): Propulsion of the bolus into the pharynx under coordinated control with the pharyngeal muscles.
• Speech and articulation: Precise tongue movements form many consonants and vowels; see further reading on articulation at speech production.

Development, variation and comparative notes

The tongue develops from several pharyngeal arches, which explains its complex innervation. Its size, shape and surface pattern vary between individuals and species. In animals, tongues may be adapted for lapping, grasping, or specialized feeding behaviors.

Clinical significance and care

Common conditions include inflammation (glossitis), fungal infection (oral candidiasis), geographic tongue (benign migratory glossitis), ankyloglossia ("tongue-tie") and neoplasms such as squamous cell carcinoma. Macroglossia (enlarged tongue) can affect breathing and speech and may contribute to sleep-disordered breathing. Examination of the tongue is a routine part of oral and general physical assessment: clinicians inspect color, texture, lesions, mobility and strength. Persistent pain, ulcers that do not heal, unexplained lumps or sudden changes in taste or mobility warrant medical evaluation. Basic care includes good oral hygiene, hydration and avoidance of irritants; specialist interventions range from conservative therapy to surgical procedures such as frenotomy or partial glossectomy in selected cases.

Notable points

Assertions that the tongue is the "strongest" muscle depend on the measure used and are not precise. The organ performs multiple coordinated tasks that make it essential for nutrition, communication and taste. For further trusted clinical summaries and images consult professional anatomy and oral health sources such as anatomy resources and oral health pages.