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Tongue

Original Editor - Shreya Trivedi

Top Contributors - Shreya Trivedi, Uchechukwu Chukwuemeka and Oyemi Sillo

Description

The tongue is an oval-shaped, pink, moist, solid, conical, muscular organ in a hollow mouth cavity. As seen in the diagram it has various structures around it and several attachments. It moves freely from the anterior side which is not directly attached to any other structure. The posterior part of the tongue is attached to numerous structures thus why the Tongue plays several important roles such as facilitation of gustatory stimuli, mastication, and speech pathway, as it helps with articulation.[1][2] In the video entitled Surface anatomy of the tongue (preview) - Human Anatomy and muscles of tongue by Kenhub the overview of Anatomy of tongue is explained. For further understanding of muscles of tongue and tongue movements, this can is also a helpful watch.

Anatomical Relationships

  • Anterior and lateral - teeth
  • Superior - hard and soft palates
  • Inferior - mucosa of the floor of the oral cavity, sublingual salivary glands, posterior wall of the oropharynx
  • Posterior - epiglottis, pharyngeal inlet
  • Lateral - palatoglossal and palatopharyngeal arches[2]

The mylohyoid muscle is responsible for raising the body of the tongue in high vowels and velar consonants. The hyoglossus pulls it downwards (and slightly backwards). The styloglossus pulls the tongue upwards and backwards. The genioglossus forms the bulk of the inferior part of the tongue and pulls the body of the tongue forward.

Muscles

The tongue is made of 2 main types of group of muscles the Intrinsic group and the Extrinsic group muscles

Total 4 types of Intrinsic muscle

  • The superior longitudinal lingual muscle shortens the tongue and curls it upward.
  • The inferior longitudinal lingual muscle shortens the tongue and curls it downward.
  • The transverse lingual muscle, which elongates and narrows the tongue.
  • The vertical lingual muscle flattens the tongue

The extrinsic muscles are

  • The genioglossus muscle protrudes from the tongue
  • The hyoglossus muscle depresses and retracts the tongue
  • The styloglossus muscle draws up the sides of the tongue to create a trough for swallowing following adequate mastication. The pair of styloglossus muscles work together on each side to retract the tongue.
  • The palatoglossus muscle, which elevates the posterior tongue, closes the oropharyngeal isthmus, aids in the initiation of swallowing, and prevents the spill of saliva from the vestibule into the oropharynx by maintaining the palatoglossal arch.

See the video below

[3]
[4]

Function

Areas of tongue-Taste function


The tongue plays several roles in taste, speech, and swallowing in the oral cavity.

  • Function of Taste(Gustation):  Taste buds situated in the tongue play a role in taste identification. Taste receptors identify taste in 5 categories Sweet, Sour, Salty, Bitter, and Umami.[5]
  • Function of Speech(Phonation): tongues movement against teeth, palate and within the oral cavity helps in the production of speech
  • Swallowing and food manipulation(Deglutition): food manipulation occurs in the oral cavity, the tongue presses food against the hard palate and enables mastication, forms the food bolus and promotes swallowing. [6][5][7]

Nerve

The motor supply of all Intrinsic and extrinsic muscles is done by cranial nerve XII (Hypoglossal) except one which is palatoglossus. Palatoglossus is supplied by Cranial nerve X (Vagus)[1][8]

Sensory supply of tongue

  • Taste sensation of anterior two third- chorda tympani (branch of the facial nerve), general sensation of the same by the lingual nerve(branch of the trigeminal nerve)
  • Taste sensation and general sensations  of the posterior two-thirds are supplied by the glossopharyngeal nerve
  • Perception taste is also partly performed by epiglottis and epiglottic regions. Taste and general sensation are provided by the internal laryngeal branch of the vagus nerve. [1][2][8]

Blood Supply

Blood supply to the tongue is predominantly from the lingual artery, a branch of the external carotid artery between the superior thyroid artery and the facial artery[6][7]

Clinical relevance

According to the main 3 functions of the tongue; Function of Taste, Function of Speech, and Function of Swallowing and food manipulation, Considering assessment of the tongue all 3 functions have to be tested and treated.

Assessment

tongue assessment plays a significant role in tongue rehabilitation[9] and maxillo-facial physiotherapy.[10] [11] Tongue strength technique[12][13]

  1. Assessment of the function of Taste[14]
  3. Assessment of the function of Speech[15]
  4. Assessment of the function of Swallowing and food manipulation[16]

Treatment

Physiotherapy plays an important role in regaining the function of the tongue. Tongue rehabilitation An Approach to improve various tongue functions: the concept of tongue rehabilitation was introduced by Mrs Fournier years ago, this includes tongue correction of tongue immaturity, resting position of the tongue, deglutition and phonation. These changes might involve adaptive cortical neuroplasticity. Indeed these last years it has been shown in humans that standardised and calibrated tongue lift or protrusion exercises induce such plasticity in the tongue motor cortex.[17] Devices are available for compressing an air-filled bulb between the tongue and hard palate and for Lingual Strength improvement. patient with stroke and other conditions which affect the function of the tongue or cause dysphagia shows positive changes after tongue rehabilitation. [18] Several techniques of tongue stretching are also beneficial. for performing the same patient positioned in sitting, the patient is supposed to protrude tongue as much as possible. with the help of a dry gaze, the therapist then grasps the tongue tightly with both hands and pulls until painless. At this time, The intervention period was 4 weeks, 5 days a week, 30 times a day. The measurement site was measured from the centre of the upper lip to the tip of the tongue out of the lips during tongue[17]

Links

References

  1. ↑ 1.0 1.1 1.2 Dotiwala AK, Samra NS. Anatomy, Head and Neck, Tongue. [Updated 2021 Apr 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507782/
  2. ↑ 2.0 2.1 2.2 Tongue [Internet]. Kenhub. 2022 [cited 7 January 2022]. Available from: https://www.kenhub.com/en/library/anatomy/tongue
  3. ↑ Dr G Bhanu Prakash Animated Medical Videos. Tongue Gross Anatomy (Animation): Dr G Bhanu Prakash. Available from: http://www.youtube.com/watch?v=zg2DpqtM7wc [last accessed 30/12/2024]
  4. ↑ BlueLink: University of Michigan Anatomy. Tongue musculature. Available from: https://www.youtube.com/watch?v=u5AQKmfknuA[last accessed 30/12/2024]
  5. ↑ 5.0 5.1 AlJulaih G, Lasrado S. Anatomy, Head and Neck, Tongue Taste Buds [Internet]. Ncbi.nlm.nih.gov. 2022 [cited 7 January 2022]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539696/
  6. ↑ 6.0 6.1 The tongue: structure and function relevant to disease and oral health. SADJ. 2003;58(9):375-383.
  7. ↑ 7.0 7.1 FUCCI D, PETROSINO L. The Human Tongue: Normal Structure and Function and Associated Pathologies. Speech and Language. 1981;:305-374.
  8. ↑ 8.0 8.1 Mu L, Sanders I. Human tongue neuroanatomy: Nerve supply and motor endplates. Clinical Anatomy. 2010;23(7):777-791.
  9. ↑ Milazzo M, Panepinto A, Sabatini A, Danti S. Tongue Rehabilitation Device for Dysphagia Patients. Sensors. 2019;19(21):4657.
  10. ↑ Gil H, Fougeront N. Tongue dysfunction screening: assessment protocol for prescribers. Journal of Dentofacial Anomalies and Orthodontics. 2015;18(4):408.
  11. ↑ Gil H, Fougeront N. Treatment of tongue dysfunction: rehabilitation for prescribers’ practice. Journal of Dentofacial Anomalies and Orthodontics. 2018;21(4):504.
  12. ↑ Maia A, Furlan R, Moraes K, Amaral M, Medeiros A, Motta A.Tongue strength rehabilitation using biofeedback: a case report:CoDAS. 2019;31(5).
  13. ↑ Solomon N. Assessment of tongue weakness and fatigue. International Journal of Orofacial Myology. 2004;30(1):8-19.
  14. ↑ Ahne G, Erras A, Hummel T, Kobal G. Assessment of Gustatory Function using Tasting Tablets. The Laryngoscope. 2000;110(8):1396-1401.
  15. ↑ Hiiemae K, Palmer J. Tongue Movements in Feeding and Speech. Critical Reviews in Oral Biology & Medicine. 2003;14(6):413-429.
  16. ↑ Agarwal J, Palwe V, Dutta D, Gupta T, Laskar S, Budrukkar A et al. Objective Assessment of Swallowing Function After Definitive Concurrent (Chemo) Radiotherapy in Patients with Head and Neck Cancer. Dysphagia. 2011;26(4):399-406.
  17. ↑ 17.0 17.1 Gil H, Fougeront N. Treatment of tongue dysfunction: rehabilitation for prescribers’ practice. Journal of Dentofacial Anomalies and Orthodontics. 2018;21(4):504.
  18. ↑ Robbins J, Kays S, Gangnon R, Hind J, Hewitt A, Gentry L et al. The Effects of Lingual Exercise in Stroke Patients With Dysphagia. Archives of Physical Medicine and Rehabilitation. 2007;88(2):150-158.
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