Lips tongue and palate

Contents:
INTRODUCTION
PHARYNGEAL ARCHES
DEVELOPMENT OF LIPS
DEVELOPMENT OF TOUNGE
DEVELOPMENT OF PALATE
CONCLUSION
REFERENCES

1. DEVELOPMENT OF LIP,TONGUE AND PALATE M.RAVINDRA 1 ST MDS

2. INTRODUCTION PHARYNGEAL ARCHES DEVELOPMENT OF LIPS DEVELOPMENT OF TOUNGE DEVELOPMENT OF PALATE CONCLUSION REFERENCES CONTENTS

3. Development “Process of maturation” Definition “All naturally occurring unidirectional changes in the life of an individual from its existence as a single cell to its elaboration as a multifunctional unit terminating to death.” INTRODUCTION

4. EMBRYOGENESIS

5.  6 cylindrical thickenings develop from the lateral wall of pharynx.(5,6 transient) They expand ventro medially from lateral wall of pharynx to their anatomical counterpart. Separates primitive stomatodeum from developing heart. PHARYNGEAL ARCHES

6. Pharyngeal Apparatus include: - Pharyngeal pouches (endoderm) Branchial grooves/clefts (ectoderm)

7. Neural crest cells and Paraxial mesoderm tissue Pharyngeal arches

8. DEVELOPMENT OF NASOMAXILLARY COMPLEX

9. Stomatodeum delimited by, frontal prominence-cranially & cardiac bulge-caudally Buccopharyngeal membrane breaks down & communicate directly with foregut Laterally stomatodeum limited by the first pair of pharyngeal arch forms in the pharyngeal wall result of proliferating mesoderm and reinforcement by migrating neural crest cells.

10. UPPER LiP : Development of lips Growth of frontonasal process Development of nasal placods Development of lateral and medal nasal processes

11. M axillary process Maxillary process Medial nasal process Medial nasal process Lateral nasal process Lateral nasal process Upper lip

12. 4 to 5 weeks of embryo

13. 5 to 6 weeks of embryo

14. 7 to 9 weeks of embryo

15. 10 th week of embryo

16. Lower lip: Lower lip develops from Mandibular process develops from 1 st pharyngeal arch. Mandibular processes from each side grow ventrally towards to the mid line and fuse in the midline to form lower boarder of stomotodeum i.e. lower lip.

17. Cleft lip Unilateral/ Bilateral Developmental defects of lips

18. Complete/ partal cleft lip

19. Midline Mandibular cleft: very rare condition Oblique facial cleft:

20. Macrostomia : Microstomia :

21. Tongue is the largest single muscular organ inside the oral cavity, which lies relatively free. Tongue develops in relation to the pharyngeal arches. It starts at 4 th week of IU life. Its development can be studied in two parts, they are •formation of anterior 2/3rd of the tongue •formation of posterior 1/3rd of the tongue Development of tongue

22. Formation of anterior 2/3rd of the tongue: Tuberculum Impar : first a swelling arises in the midline of the mandibular process. And is flanked by two other swellings. Lingual Swelling : The lateral part of the mandibular process mesenchymal thickening develops to form two lingual swellings.

23. Swellings merges with each other and forms the mucous membrane of ant 2/3rd of the tongue. These lateral swelling quickly enlarge and merge with each other and the tuberculum impar to form a large mass from which mucous membrane of the anterior 2/3rd of the tongue is formed. Ant 2/3rd is supplied by Trigeminal nerve. 

24. Formation of posterior 1/3rd of the tongue: Root of the tongue arises from large midline swelling develops from mesenchyme of 2nd,3rd and 4th arches. Consist of , 1. Copula (associated with 2nd arch) 2. A large hypobranchial eminence (associated by 3,4th acrh ) 

25. Hypobranchial eminence overgrows the copula. The tongue separates from the floor of the mouth by a down- growth of ectoderm around its periphery, which degenerates to form lingual sulcus and gives the tongue mobility. Post 1/3rd is supplied by glossopharyngeal nerve. Muscle of the tongue have a different origin, they arises from the occipital somites , which have migrated forward in to the tongue area, carrying with them their nerve supply hypoglossal nerve. 

26. Macroglossia Some congenital syndromes often express macroglossia in their phenotypes, most commonly Down syndrome. The two broadest categories true macroglossia and pseudomacroglossia . Physical examination of the oral cavity and head morphology is helpful to differentiate true macroglossia from pseudomacroglossia . Other causes are: Hypothyroidism Acromegaly . DEVELOPMENTAL DEFECTS OF TONGUE

27. Microglossia and Aglossia E tiology some sort of fetal cell traumatism in the first few weeks of gestation . Aglosia syndrome is in reality a microglossia with extreme glossoptosis . Glossoptosis  is a medical condition and abnormality which involves the downward displacement or retraction of the tongue.

28. Ankyloglossia or tounge tie It is said to exist when the inferior frenulum attaches to the bottom of the tongue and subsequently restricts free movement of the tongue . Ankyloglossia superior

29. Benign migratory glossitis : The etiology of benign migratory glossitis is unknown. but it does seem to become more prominent during conditions like psychological stress and it is found with Increased frequency in persons with psoriasis of the skin . Median rhoboied glossitis : The posterior dorsal point of fusion is occasionally defective, leaving a rhornboid -shaped Smooth erythematous mucosa lacking in papillae or taste buds.

30. Bifid tongue A completely cleft or bifid tongue is a rare condition that is apparently due to lack of merging of the lateral lingual swellings of this organ . Fissured tongue A definitive etiology is unknown. Fissured tongue is also seen in Melkersson -Rosenthal syndrome and Down syndrome and in frequent association with benign migratory glossitis {geographic tongue}.

31. Lingual thyroid nodule The lingual thyroid is an anomalous condition in which follicles of thyroid tissue are found in the substance of the tongue. The thyroid gland develops in the embryo from the ventral floor of the pharynx by means of an endodermal invagination or diverticulum . The tongue Forms at the same time from this pharyngeal floor and is anatomically associated with the thyroid gland by connection through the thyroglossal tract the lingual remnant of which is known as the foramen caecum .

32. The palate is the tissue that interposes between the oral & nasal cavities. It develops from two parts The Primary Palate The Secondary Palate Development of palate occurs in 5 to 9 weeks of embryo.  Development of palate

33. Development Of The Primary Palate : Fusion of the two medial process with the fronto nasal process results in the formation of primary palate. Development of Secondary Palate: The formation of secondary palate commences between 7 and 8 weeks and completes around the 3rd month of the gestation. Three outgrowth appear in the oral cavity 1. The two palatal process 2. The nasal septum

34. Oronasal membrane

35. Each palatal process grows downwards first then upwards after the withdrawal of tongue(7th week) -septum and the two shelves converges and fuse in the midline  The closure of the secondary palate proceeds gradually form the primary palate in a posterior direction.

36. 7 th week of ilu is very important as maximal development of lip &palate occurs. Any vascular deficiancy at this time may result in O2 & nutritional deficiency  results in Cleft palate and lip. Developmental defects of palate:

37. Cleft palate:

38. Ten cate`s oral histology, 8 th edition. Shafer`s text book of Oral pathology 6 th edition. Human ebryology by Inderbir Singh, 7 th edition. Refferences :