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Portrait of Tongue

Anatomy · Eye, ear & senses

Tongue

The muscular organ of taste, speech and swallowing

Oral cavity · floor of the mouth

A muscular organ attached to the floor of the mouth, the hyoid bone and the mandible, made of eight muscles, four intrinsic and four extrinsic pairs, and covered by a mucous membrane bearing papillae. A V-shaped groove divides it into an oral anterior two-thirds and a pharyngeal posterior third. It shapes food and speech, and its surface carries taste buds and general sensation.

How to spot them

  • ▸A V-shaped groove, the sulcus terminalis, with a small pit (the foramen caecum) at its apex, separates the front two-thirds from the back third
  • ▸Four kinds of papillae: filiform, fungiform, foliate and circumvallate
  • ▸Anchored to the floor of the mouth by a midline fold, the frenulum
  • ▸Its muscles are supplied by the hypoglossal nerve, except palatoglossus

What to know

Sticks out to one side towards the side of a lesion when the nerve to its muscles is damaged

The tongue deviates to the affected side in hypoglossal (XII) nerve palsy, from weakness of genioglossus

A row of eight to twelve large mushroom-shaped structures, set in a V just in front of the groove, each ringed by a moat

The circumvallate papillae of the tongue, cleaned by the glands of von Ebner

A pit at the apex of the V, marking where a gland of the neck began its descent in the embryo

The foramen caecum of the tongue — the origin of the thyroid gland, via the thyroglossal duct

The front two-thirds are served by the lingual nerve for touch and the chorda tympani for taste; the back third by the glossopharyngeal nerve for both

The sensory innervation of the tongue

Attached at its underside by a fold of mucous membrane that, if too short, is snipped in babies who cannot feed

The lingual frenulum; ankyloglossia or 'tongue-tie'

A 'map' with sweet at the tip and bitter at the back, resting on a misreading of a German paper of 1901 by David Hänig (1901)

The tongue map — a myth; all tastes can be detected across the tongue

A muscular hydrostat, like an elephant's trunk or an octopus's arm, moved by muscles running in three directions

The tongue: four intrinsic and four extrinsic paired muscles

Hairlike, pointed projections that are the commonest on its surface and carry no taste buds

The filiform papillae, which give the tongue its rough texture

Key ideas

  • The four extrinsic muscles (genioglossus, hyoglossus, styloglossus and palatoglossus) move the tongue as a whole, while the intrinsic muscles change its shape, without any skeletal support.
  • Taste and touch travel by different nerves. The front two-thirds is developed from the first arch (lingual, V3) and the back third from the third arch (glossopharyngeal).

Quick-fire facts

  • •Eight muscles: four intrinsic pairs and four extrinsic pairs (genioglossus, hyoglossus, styloglossus, palatoglossus)
  • •All are supplied by the hypoglossal nerve (XII) except palatoglossus, which is supplied by the vagus via the pharyngeal plexus
  • •The taste buds sit on fungiform, foliate and circumvallate papillae, but filiform papillae have none
  • •Blood supply is chiefly from the lingual artery, a branch of the external carotid
  • •The lingual tonsil lies on the pharyngeal (posterior) third
  • •A typical adult has roughly 2,000–8,000 taste buds, depending on the estimate; they are replaced about every ten days to two weeks
  • •The five accepted basic tastes are sweet, sour, salty, bitter and umami; umami was identified by Kikunae Ikeda in Tokyo in 1908
  • •The tongue is not the strongest muscle in the body; it is unusual because it is attached at only one end

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Sources