Development of tongue and its applied anatomy
- 1. DEVELOPMENT OF TONGUE AND ITS APPLIED ANATOMY. PRESENTED BY: DR. RITU RANDAD 1
- 2. CONTENT Introduction Parts of Tongue Muscles of the Tongue Intrinsic muscles Extrinsic muscles Arterial supply of Tongue Venous Drainage 2
- 3. Lymphatic Drainage Nerve Supply • Motor nerves • Sensory nerves Development of Tongue Applied aspect : Anomalies, clinical features and its management 3
- 4. Introduction 4 The tongue is a muscular organ situated in the floor of the mouth. It is associated with the functions of 1. Taste 2. speech 3. chewing 4. deglutition and 5. cleansing of mouth. B D Chaurasia’s Human Anatomy, 7th edition, vol 3
- 5. Parts of tongue 5 The tongue has: A root A tip A body, which is subdivided into: A curved upper surface or dorsum. An inferior surface B D Chaurasia’s Human Anatomy, 7th edition, vol 3
- 6. The root of the tongue 6 The root is attached to the styloid process and soft palate above to mandible and the hyoid bone below. In between the mandible and hyoid bone, and it is related to geniohyoid and mylohyoid muscles. B D Chaurasia’s Human Anatomy, 7th edition, vol 3
- 7. THE TIP OF THE TONGUE The tip of the tongue forms the anterior free end which, at rest, lies behind the upper incisor teeth. 7 B D Chaurasia’s Human Anatomy, 7th edition, vol 3
- 8. Dorsum of the tongue The dorsum is divided into oral and pharyngeal parts by a V- shaped, the sulcus terminalis. It is convex in all directions. It is divided into: An oral part or anterior two-thirds. A pharyngeal or posterior one-third, by a faint V-shaped groove, the sulcus terminalis. The small posterior most part. 8 B D Chaurasia’s Human Anatomy, 7th edition, vol 3
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- 10. 1. The oral part placed at floor of the mouth. 2. Superior surface has median furrow has papillae. 3. Inferior surface has smooth mucous membrane 10
- 11. 11 B D Chaurasia’s Human Anatomy, 7th edition, vol 3 On other side of frenulum, prominence produced by deep lingual veins. Laterally a fold called plica fimbriata goes towards tip of tongue.
- 12. 2.The pharyngeal or lymphoid part of the tongue lies behind palatoglossal arches and the sulcus terminalis. 3. The posterior most part of the tongue is connected to epiglottis by three-folds of mucous membrane. These are median glossoepiglottic fold, 12
- 13. PAPILLAE OF TONGUE 13 WHAT IS A PAPILLAE? These are projections of mucous membrane or corium which gives the anterior two-thirds of the tongue, its characteristic roughness. These are of four types: Vallate or circumvallate Fungiform Foliate Filiform B D Chaurasia’s Human Anatomy, 7th edition, vol 3 Vallate papillaeFoliate Fungiform Filiform
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- 15. i. Vallate or circumvallate papillae: o Size: Large in size about 1-2 mm in diameter o 8-12 in number o location: immediately in front of the sulcus terminalis. o structure: The walls of the papilla(is cylindrical projection surrounded by circular sulcus) having taste buds. 15
- 16. ii. The fungiform papillae: o location :Numerous near the tip and margins of the tongue, over the dorsum. o structure: Each papillae has a narrow pedicle and large rounded head. o color : bright red color. 16 B D Chaurasia’s Human Anatomy, 7th edition, vol 3
- 17. 17 iii. Filiform papillae or conical papillae: location: Covers the presulcal area of the dorsum of the tongue. velvety appearance. size: smallest and numerous Each is pointed and covered with keratin, the apex is often split into filamentous processes.
- 18. Foliate papillae: o Location: Present at lateral border just in front of papillae o Shape: They are leaf shaped. 18
- 19. MUSCLES OF THE TONGUE LONGITUDINAL : A. SUPERIOR B. INFERIOR TRANSVERE VERTICAL A middle fibrous septum divides tongue into right and let halves. Each half contains 4 intrinsic and 4 extrinsic muscles. Intrinsic muscles: They occupy the upper part of the tongue, and are attached to the submucous fibrous layer and to the median fibrous septum. 19 B D Chaurasia’s Human Anatomy, 7th edition, vol 3
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- 24. 24ACTIONS OF
- 26. Extrinsic muscles 1. Genioglossus 2. Hyoglossus 3. Styloglossus 4. Palatoglossus The extrinsic muscles connect the tongue to the mandible via genioglossus, to the hyoid bone through hyoglossus, to styloid process via styloglossus, and the palate via palatoglossus. 26 B D Chaurasia’s Human Anatomy, 7th edition, vol 3
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- 32. ARTERIAL SUPPY OF TONGUE 32 It is derived from the tortuous lingual artery, a branch of the external carotid artery. a) The root of the tongue by tonsillar artery, a branch of facial artery, b) and ascending pharyngeal branch of external carotid artery. B D Chaurasia’s Human Anatomy, 7th edition, vol 3
- 33. VENOUS DRAINAGE 33 Two venae comitantes supplement with the lingual artery, and one vena comitant accompanies the hyoglossal nerve. I. The deep lingual vein is the largest and principal vein of the tongue. II. It is seen on the inferior surface of the tongue. B D Chaurasia’s Human Anatomy, 7th edition, vol 3
- 34. It runs backwards and crosses the genioglossus and the hyoglossus below the hypoglossal nerve. These veins unite at the posterior border of the hyoglossus to form the lingual vein which ends in the internal jugular vein. 34
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- 36. Motor Nerves All the intrinsic and extrinsic muscles, except the palatoglossus are supplied by the hypoglossal nerve(XII CN). The palatoglossus is supplied by the cranial root of the accessory nerve(XI CN) So seven out of eight muscles are supplied by XII cranial nerve. 36 Nerve supply B D Chaurasia’s Human Anatomy, 7th edition, vol 3
- 37. 37 Sensory nerve supply of tongue The lingual nerve is the nerve of general sensation and the chorda tympani is the nerve for the taste of the anterior two-thirds of the tongue except vallate papillae. The glossopharyngeal nerve(IX CN) is the nerve for both general sensation and taste for the posterior one-third of the tongue including the circumvallate papillae. The posterior most part of the tongue is supplied by the vagus nerve(X CN) through the internal laryngeal branch. B D Chaurasia’s Human Anatomy, 7th edition, vol 3
- 38. COMPARISON OF PARTS OF THE TONGUE :-Situation :-Structure :-Function :-Sensory nerve :-Sensation of taste :-Development of epithelium from endoderm Anterior two-third -Lies in mouth cavity -Contains papillae -Chewing -Lingual nerve -Chorda tympani except circumvallate papillae -Lingual swellings of 1st arch. Tuberculum impar which soon disappears Posterior one-third -Oropharynx -Has lymphoid tissue -Deglutition -Glossopharyngeal nerve -Glossopharyngeal including the vallate papillae -Third arch which forms large ventral part of hypobranchial eminence 38 Posteriormost part and vallecula -Oropharynx - ----- -Deglutition -Internal laryngeal branch of vagus -Internal laryngeal branch of vagus - Forth arch which forms small dorsal part of hypobranchial eminence B D Chaurasia’s Human Anatomy, 7th edition, vol 3
- 39. 39 HISTOLOGY The tongue forms in the ventral floor of the pharynx after arrival of the hypoglossal muscle cells. It is known that the anterior two-thirds of the tongue is covered by ectoderm whereas endoderm covers the posterior one-third. A residual pit left in the epithelium at the site of invagination marks the junction between the anterior two-thirds and posterior one-thirds of the tongue. B D Chaurasia’s Human Anatomy, 7th edition, vol 3 th
- 40. The mucous membrane consists of a layer of connective tissue, lined by stratified squamous epithelium. On the oral part of the dorsum, it is thin, forms papillae, and is adherent to the muscles. On the pharyngeal part of the dorsum, it is very rich in lymphoid follicles. On the inferior surface, it is thin and smooth. Numerous gland, both serous and mucous lie deep to the mucous membrane. 40 B D Chaurasia’s Human Anatomy, 7th edition, vol 3 Orban’s oral histology and embryology, 14th edition
- 41. STRUCTURE There are two types of cells, the supporting cells and gustatory cells. The supporting cells are spindle- shaped Gustatory cells are long slender and centrally situated. 41 B D Chaurasia’s Human Anatomy, 7th edition, vol 3 Orban’s oral histology and embryology, 14th edition
- 42. The bulk of the tongue is made up of straited muscles. I. Taste buds are most numerous on the sides of the circumvallate papillae II. walls of the surrounding sulci, III. foliate papillae, IV. posterior one-third of the tongue; are sparsely distributed on the fungiform papillae, the soft palate, the epiglottis and the pharynx. No taste buds on the mid-dorsal region. 42 B D Chaurasia’s Human Anatomy, 7th edition, vol 3 Orban’s oral histology and embryology, 14th edition TASTE BUDS
- 43. DEVELOPMENT OF TONGUE 43 • The tongue develops in relation to the pharyngeal arches in the floor of the developing mouth. • The medial most parts of the mandibular arches proliferate to form two lingual swellings. • The two swellings are separated from each other by another swelling that appears in the midline. Orban’s oral histology and embryology, 14th edition Human embryology, 8th edition
- 44. 44 The swelling is called tuberculum impar. The anterior two-thirds of the tongue is formed by fusion of: a. The tuberculum impar, and b. Two lingual swellings. The anterior two- thirds is thus derived from the mandibular arch. Anterior two-thirds: which arises from the first branchial arch. Therefore, supplied by lingual nerve of 1st arch and chorda tympani of 2nd arch. Orban’s oral histology and embryology, 14th edition Human embryology, 8th edition
- 45. 45 The posterior one-third is derived from the cranial part of hypobranchial eminence.(2nd, 3rd, and 4th). The 2nd arch mesoderm gets buried below surface. Orban’s oral histology and embryology, 14th edition Human embryology, 8th edition
- 46. The 3rd arch grows over the 2nd to fuse with mesoderm of 1st arch. THUS POSTERIOR ONE-THIRD IS FORMED BY 3RD ARCH MESODERM. Posterior one-third: From cranial large part of the hypobranchial eminence, i.e; from the third arch. So it supplied by glossopharyngeal nerve. 46 Orban’s oral histology and embryology, 14th edition Human embryology, 8th edition Orban’s oral histology and embryology, 14th edition Human embryology, 8th edition
- 47. The posterior most part of the tongue is derived from the 4th arch. This is supplied by superior laryngeal nerve, which is nerve of fourth arch. 47 Orban’s oral histology and embryology, 14th edition Human embryology, 8th edItion
- 48. MUSCULATURE OF TONGUE Derived from occipital myotomes. nerve supply from hypoglossal nerve. EPITHELIUM OF TONGUE Made firstly from a single layer of cells. Later, becomes stratified and papilla becomes evident. Taste buds are formed in relation to the terminal branches of the innervating nerve fibres. 48 Orban’s oral histology and embryology, 14th edition Human embryology, 8th edition
- 49. Diseases of tongue A. INHERITED, CONGENITAL, AND DEVELOPMENTAL ANOMALIES. B. DISORDERS OF LINGUAL MUCOSA. C. MALIGNANT TUMORS OF THE TONGUE.
- 50. Ankyloglossia or tongue- tie 50 Developmental condition characterized by fixation on tongue in the floor of the mouth. PREVALENCE: 1.7% of infants CLINICAL FEATURES: speech defects sounds:- l, r, t, d, n th ,sh and z. Deformity in dental occlusion. Difficulties in swallowing TREATMENT: Frenulectomy is recommended. Ghom’s, Textbook of oral medicine. 3rd edition th
- 51. MACROGLOSSIA 51 (tongue hypertrophy, enlarged tongue, pseudomacroglossia) CLINCIAL FEATURES: Related to syndromes like Down syndrome and Beckwith- Wiedemann syndrome. Two headings are true macroglossia and pseudomacroglossia. i. Dyspnea - difficult, noisy breathing, obstructive sleep apnea or airway obstruction. ii. Dysphagia - difficulty swallowing and eating. iii. Dysphonia - disrupted speech, possibly manifest as lisping. iv. Sialorrhea - drooling. v. Angular cheilitis - sores at the corners of the mouth. TREATMENT: The surgery is the choice of treatment. Ghom’s, Textbook of oral medicine. 3rd edition Shafer’s textbook of Oral Pathology, 7th edition
- 52. MICROGLOSSIA AND AGLOSSIA 52 (Abnormally small tongue; Decreased size of tongue; Hypoglossia; Hypoplasia of the tongue; Hypoplastic tongue) There is tiny or rudimentary tongue present in the oral cavity. microglossia with extreme glossoptosis. Treatment: orthognathic surgery Speech and language development Ghom’s, Textbook of oral medicine. 3rd edition Shafer’s textbook of Oral Pathology, 7th edition
- 53. FISSURED TONGUE 53 (scrotal tongue, lingua plicata) Fissured tongue is characterized by grooves that vary in depth and noted along the dorsal and lateral aspects of the tongue. PREVALENCE: as high as 21%. CLINCIAL FEATURES: the depth can be 6mm in diameter. Lesions are generally asymptomatic unless debris is entrapped within the fissure other than sensitivity to hot and spicy foods. TREATMENT: No definite therapy or medication. Ghom’s, Textbook of oral medicine. 3rd edition
- 54. GEOGRAPHIC TONGUE 54 (benign migratory glossitis) The lesions often heal in one area and then move (migrate) to a different part of your tongue so also named as migratory glossitis. Is a psoriasiform mucositis of the dorsum of the tongue. PREVALENCE : 1-2% CLINICAL FEATURES: Constant changing pattern of serpiginous white lines on areas of smooth, depapillated mucosa. Discomfort, pain or burning sensation in some cases, most often related to eating spicy or acidic foods. TREATMENT: No specific treatment. : Symptomatic lesions can be treated with prednisolone and a tropical or systemic anti-fungal medication. Ghom’s, Textbook of oral medicine. 3rd edition
- 55. CANDIDIASIS 55 Most common intraoral opportunistic fungal infection . Causative agent: Candida albicans. CLINICAL FEATURES: Redness :Burning or soreness that may be severe enough to cause difficulty eating or swallowing. TREATMENT: Antifungal medicine applied to the inside of the mouth for 7 to 14 days. These medications include clotrimazole, miconazole, or nystatin. Ghom’s, Textbook of oral medicine. 3rd edition
- 56. PERNICIOUS ANEMIA 56 Most common forms of vitamins B12 deficiency. CLINICAL FEATURES: Beefy red tongue Erythematous areas on the tip and margins De-papillation Candidal infection. TREATMENT: the disease is relatively easy to treat with B-12 injections or supplements. Ghom’s, Textbook of oral medicine. 3rd edition Shafer’s textbook of Oral Pathology, 7th edition
- 57. SQUAMOUS CELL CARCINOMA OF TONGUE 57 60% of lesions arises from the anterior two-thirds of the tongue. CLINICAL FEATURES: It develop into a necrotic looking ulcer with irregular, raised indurated borders, or into a broad based exophytic mass with a surface texture which may be verrucous, pebbled or relatively smooth. When traumatized, oral SCC bleeds readily and often becomes superficially secondarily infected. Oral SCC is usually painless unless it is- secondarily infected. Large lesions may interfere with normal speech, mastication or swallowing. TREATMENT: the affected side of the tongue is removed surgically. All the deep cervical lymph nodes are also removed, i.e. block dissection of the neck. Ghom’s, Textbook of oral medicine. 3rd edition Shafer’s textbook of Oral Pathology, 7th edition
- 58. References B D Chaurasia’s Human Anatomy, 7th edition, vol 3 Human embryology, 8th edItion Ghom’s, Textbook of oral medicine. 3rd edition Shafer’s textbook of Oral Pathology, 7th edition 58
- 59. THANK YOU 59