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

2. M.RAVINDRA
1ST MDS

3.  INTRODUCTION
 PHARYNGEAL ARCHES
 DEVELOPMENT OF LIPS
 DEVELOPMENT OF TOUNGE
 DEVELOPMENT OF PALATE
 CONCLUSION
 REFERENCES

4.  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.”

7.  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.

9.  Pharyngeal Apparatus
include: -
• Pharyngeal pouches
(endoderm)
• Branchial grooves/clefts
(ectoderm)

10. Neural crest cells
and
Paraxial mesoderm
tissue
Pharyngeal arches

12.  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.

14.  UPPER LiP:
Growth of frontonasal
process
Development of nasal
placods
Development of lateral
and medal nasal
processes

15. Maxillary
process
Maxillary
process
Medial
nasal
process
Medial
nasal
process
Lateral
nasal
process
Lateral
nasal
process
Upper lip

17. 4 to 5 weeks of embryo

18. 5 to 6 weeks of embryo

19. 7 to 9 weeks of embryo

20. 10th week of embryo

21. Lower lip:
 Lower lip develops from
Mandibular process
develops from 1st
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.

22.  Cleft lip
Unilateral/ Bilateral

23.  Complete/ partal cleft lip

24.  Midline Mandibular cleft: very rare condition
 Oblique facial cleft:

25.  Macrostomia:
 Microstomia:

26.  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 4th 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

28. 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.

29.  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.

30. 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)

31.  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.

32.  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.

33.  Microglossia and Aglossia
Etiology
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.

34.  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

35.  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.

36.  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}.

37.  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.

38.  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.

39. 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

40. Oronasal
membrane

43.  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.

44.  7th 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.

45. Cleft palate:

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