Structural arrangement of the intrinsic muscles of the tongue and their relationships with the extrinsic muscles
The tongue is a dense muscular organ, in which the muscles are arranged in a confusing pattern. The intrinsic muscles were gross anatomically investigated in 25 cadavers to clarify their configuration. The superior longitudinal muscle (SLm) ran beneath the dorsal mucosa and was divided into bundles by the other muscles passing through it to the dorsum. The external bundle of the styloglossus, with the palatoglossus, coursed externally to the hyoglossus. Their fibers spread beneath the SLm or attached to the apex and the inferior longitudinal muscle (ILm) ascended from the root and joined them. The genioglossus and the anterior part of the hyoglossus extended internally and externally to the ILm, respectively, to the dorsum, and the vertical muscle was sandwiched between them. The transverse muscle passed laterally from the lingual septum. The fibers of the posterior part of the hyoglossus converged to the root and spread beneath the SLm. The intersections between these vertical and transverse fibers divided one another into bundles or lamellae. The middle bundle of the styloglossus, passing between the two parts of the hyoglossus, was divided into slips by the intersection with the genioglossus. The internal bundle of the styloglossus, with the glossopharyngeus, descended internally to the posterior part to the root. The findings indicate that the intrinsic and extrinsic muscles of the tongue are not independent groups, and their fibers form a three-dimensional latticework. Each muscle contains numerous bundles or lamellae as functional units that can act separately or cooperate across the muscles.
KeywordsHuman gross anatomy Superior longitudinal muscle Inferior longitudinal muscle Transverse muscle Vertical muscle
The author expresses special thanks to the donors of the cadavers used in this study.
Compliance with ethical standards
Conflict of interest
The author declares he has no conflict of interest.
- 4.Bergman RA, Thompson SA, Afifi AK, Saadeh FA (1988) Compendium of human anatomic variation: text, atlas, and world literature. Urban & Schwarzenberg, Baltimore, Munich, p 35Google Scholar
- 5.Blount RF, Lachman E (1953) The digestive system. In: Schaeffer JP (ed) Morris’ human anatomy, 11th edn. The Blakiston Company, New York, Toronto, pp 1292–1424Google Scholar
- 7.Grant JCB, Smith CG (1953) The musculature. In: Schaeffer JP (ed) Morris’ human anatomy, 11th edn. The Blakiston Company, New York, Toronto, pp 399–609Google Scholar
- 11.Sakamoto Y (2017) Morphological features of the branching pattern of the hypoglossal nerve. Anat Rec (In press)Google Scholar
- 13.Schäfer EA, Symington PJ (1896) The organs of digestion. In: Schäfer EA, Thane GD (eds) Quain’s elements of anatomy, vol 3, Part 4, 10th edn. Longman Green and Co., London, New York, Bombay, pp 1–145Google Scholar
- 14.Sinclair DC (1972) Muscles and Fasciae. In: Romanes GJ (ed) Cunningham’s textbook of anatomy, 11th edn. Oxford university press, London, pp 259–397Google Scholar
- 15.Standring S (2005) Head and Neck. In: Standring S, Ellis H, Healy JC, Johnson D, Williams A (eds) Gray’s Anatomy, 39th edn. Elsevier Churchill Livingstone, Edinburgh, London, New York, Oxford, Philadelphia, St Louis, Sydney, Toronto, pp 439–723Google Scholar
- 17.Thane GD (1894) Myology. In: Schäfer EA, Thane GD (eds) Quain’s elements of anatomy. vol 2, Part 2, 10th edn. Longman Green and Co., London, New York, pp 199–350Google Scholar