The tongue develops from tissues originating in the pharyngeal arches and swellings in the floor of the mouth. It begins developing at 4 weeks as a tuberculum impar surrounded by two lateral lingual swellings that merge to form the anterior two-thirds of the tongue. The root develops from the hypobranchial eminence originating in the third arch. Muscles of the tongue originate from occipital somites and are innervated by the hypoglossal nerve. The anterior two-thirds receive innervation from the trigeminal nerve and the posterior third from the glossopharyngeal nerve. The tongue separates from the floor of the mouth and develops four types of lingual papillae

1. DEVELOPMENT OF THE TONGUE by: Dr. Carmina Romero Granado

2. tongue Largest single muscular organ inside the oral cavity. Originates from the muscles of occipital myotomes Innervated by 5 th , 7 th , 9 th & 10 th cranial nerves

3. Extensive innervation is due to the long distance the muscle cells migrates to reach the tongue & varied functions performed Muscles travel in the paths of these various nerves

4. Parts of the tongue The first pharyngeal arch tissues forms the anterior (movable) body of the tongue The second & third arches form the posterior ( immovable) body & base .

5. Tissues of the tongue has 3 parts: The central tuberculum impar & Two lateral lingual swellings

6. Formation of the Tongue The tongue begins to develop at about 4 weeks Local proliferation of the mesenchyme then gives rise to a number of swellings in the floor of the mouth

7. First, a swelling ( the tuberculum impar ) arises in the midline in the mandibular process and is flanked by two other bulges, the lingual swellings

8. Very quickly these lateral lingual swellings enlarge and merge with each other and the tuberculum impar to form a large mass from which the mucous membrane of the anterior two thirds of the tongue is formed

9. The root of the tongue arises from the hypobranchial eminence , a large midline swelling developed from the mesenchyme of the third arch

10. Hypobranchial eminence is the primordial of the epiglottis (thin plate of cartilage in front of the glottis that protects it) during swallowing

11. The mesenchyme of the third arch rapidly overgrows that of the second arch, which is thereby excluded from further involvement in the development of the tongue

12. The hypobranchial eminence gives rise to the mucous covering the root, or posterior third of the tongue

13. Some authorities divide the hypobranchial eminence into an anterior copula (which gives origin to the mucosa covering the root of the tongue) and a hypobranchial eminence (which gives rise to the epiglottis)

14. The tongue separates from the floor of the mouth by a down growth of ectoderm around its periphery, which subsequently degenerates to form the lingual sulcus and gives the tongue mobility

15. The muscles of the tongue have a different origin: they arise from the occipital somites , which have migrated forward into the tongue area, carrying with them their supply, the twelfth cranial (hypoglossal) nerve

16. This unusual development of the tongue explains its innervation Since the mucosa of the anterior two thirds of the tongue is derived from the first arch, it is supplied by the fifth cranial nerve (trigeminal nerve), whereas the mucosa of the posterior third of the tongue , derived from the third arch, is supplied by the ninth cranial nerve (glossopharyngeal nerve)

17. The body & base of the tongue differ in structure of the mucous membrane: anterior (body)- papillary in nature Posterior (base)- lymphatic in nature this are separated by a V-shaped sulcus known as sulcus terminalis

18. The anterior 2/3 is divide into two lateral halves by a lingual septum w/c is manifested externally as median sulcus the dorsal mucosa covering the anterior part is velvet like in appearance because of the presence of invaginations & evaginations known as lingual papilla

19. Types of lingual papilla: 4 types of lingual papilla: Filiform Fungiform Foliate circumvalate

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