embryology, development of face, anomalies, dental, public health significance

1. DEVELOPMENT OF
FACE
1

2.  INTRODUCTION
 PHASES OF DEVELOPMENT
 PHARYNGEAL ARCHES
 FACE
 MANDIBLE
 MAXILLA
 PALATE
 NASAL CAVITIES
 SINUSES
 LIPS
 TONGUE
 SALIVARY GLAND
 TEETH
 ANOMALIES OF FACE
 PUBLIC HEALTH SIGNIFICANCE
 CONCLUSION
 REFERENCES
2

3.  Every individual spends the first nine months of its life
within the womb or uterus of its mother.
3

4.  During this period, it develops from a small one-
celled structure to an organism having billions of
cells.
 The most spectacular changes occur in the first 2
months of IUL. During these 2 months ,we call the
developing individual an embryo.
4

5. Pre-implantation
period
Embryonic
period
Foetal period
5

6. 6
 The intercellular spaces
become confluent, and
finally, a single cavity, the
blastocele, forms.
 At this time this embryo
is a blastocyst.

7. 7

8. 8
TIME PERIOD DEVELOPMENTAL STAGES
2ND WEEK Formation of amniotic cavity
Extra embryonic mesoderm
Chorionic plate formation

9. 9

10. 10
ECTODERM
• Brain & spinal cord
• Cranial & spinal
nerves
• Sensory epithelium
of ear, nose and eye
• Skin and its
appendages
• Enamel of teeth
• Pituitary gland
• Mammary glands
• Sweat glands
• Connective tisues of
head
• Parotid gland.
ENDODERM
• Epithelium of
urinary bladder
• Epithelial parts of
trachea, bronchi,
lungs, pharynx,
thyroid gland,
tympanic cavity,
tonsils, parathyroid
glands.
• Submandibular &
sublingual salivary
gland.
MESODERM
• Muscles of head
• Striated skeletal
muscles of trunk,
limbs
• Blood cells
• Lymphatic cells
• Spleen
• Adrenal cortex
• Urogenital system
gonads, ducts,
access

11.  Rod-like thickenings of
mesoderm in theforegut.
 At first 6 arches. 5th arch
disappear,only 5remains.
11

12.  Theventral endsof the archesof the
right andleft sidesmeet at the
middle line in the floor of the
pharynx.
12

13. 13
 Theybring about
elongation of the region
between the
stomatodeum andthe
pericardium forming
neck.

14. 14

15. 15
ARCH NERVE SUPPLY ARTERIAL SUPPLY MUSCLES OF ARCH
First Mandibular Maxillary artery
External carotid artery
Medial and lateral pterygoids
Masseter
Temporalis
Mylohyoid
Anterior belly of digastric
Tensor tympani
Tensor palati
Second Facial Facial artery
Stapedial artery
Facial muscles
Occipitofrontalis
Platysma
Stylohyoid
Posterior belly of digastric
Stapedius
Auricular muscles

16. ARCH NERVE SUPPLY ARTERIAL SUPPLY MUSCLES OR
ARCH
Third Glossopharyngeal Internal carotid artery
Common carotid artery
Stylopharyngeus
Fourth Superior laryngeal Subclavian artery
Sixth Recurrent laryngeal Pulmonary artery
16
Muscles of
larynx and
pharynx

17. 17

18. Mesenchymal gene expression is initially determined by
homodomain-containing transcription factors
18
Transcription
factors
OTX2
HOX

19. 19

20. ENDODERMAL
POUCHES
ORGANS FORMED
First Tongue
Auditory tube
Tubotympanic recess
Middle ear with tympanic antrum
Second Tonsil
Tubotympanic recess
Third Inferior parathyroid gland
Thymus
Fourth Superior parathyroid gland
Thyroid gland
Fifth or
ultimobranchial pouch
Caudal pharyngeal complex
20

21.  The facial components are derived from five facial
prominences
 The 5 prominences which appear around the stomodeum
are
1.Single frontonasal prominence
2.Paired maxillary prominence
3.Paired mandibular prominence
21

22.  By 4th week  center of growing face  stomodeum
 After formation of head fold, the developing brain and
pericardium forms two prominent bulgings.
22

23. 23

24. 24

25. 25

26. 26

27. 27

28.  After formation of upper & lower
lip, the Stomatodeum is very broad.
 It is bounded above by Maxillary
Process & below by Mandibular
Process.
 These processes undergo
progressive fusion with each other
to form Cheeks
28

29.  Bilateral oval thickening of the surface ectoderm-nasal
placodes have developed in the inferolateral parts of
the frontonasal prominence
 convex but later, a flat depression in each placode.
29

30.  The mesenchyme in the margins of
the placode proliferates, and
forming horse-shoe shaped
elevations-the medial and lateral
nasal prominences.
 As a result, the nasal placodes lie in
depressions, called nasal pits.
30

31. 31

32. 32
 Nasolacrimal duct
develops from a rod like
thickening of ectoderm of
nasolacrimal
groove.thickensone
end of this duct expands
and forms lacrimal
sac.drains into inferior
meatus in lateral wall of
nose.

33. 33

34.  Paranasal sinuses appear as diverticula from nasal
cavity.
 The diverticula gradually invades the bones.
 Enlargment of paranasal sinuses is associated with the
overall enlargement of the facial skeleton including the
jaws.
 This provide space in the jaws for growth and eruption
of teeth.
34

35.  Forms around 3rd month of intra-uterine life.
 Develops by expansion of nasal mucous membrane
into maxillary bone.
 Later enlarges by resorption of internal wall of
maxilla.
35

36.  The maxilla develops from a center of ossification in
the mesenchyme of the maxillary process of the first
arch.
 Center of ossification is closely associated with the
cartilage of the nasal capsule. Bone formation
spreads : – From center Posteriorly below orbit
towards forming zygoma – Anteriorly future incisor
region – Superiorly frontal process
36

37. 37
PRIMARY PALATE
SECONDARY PALATE
The primary palate represents only
a small part lying anterior to the
incisive fossa, of the adult hard
palate.
The Secondary Palate is the
primordial of hard and soft palate
posterior to the incisive fossa

38. The mesoderm in the palate undergoes intramembranous
ossification to form the hard palate.
 Ossification does not extend into the posterior portion
called as soft palate.
38

39. The part of the palate derived from frontonasal process
forms the premaxilla; which carries the incisor teeth.
 After the development of secondary palate distinction
between the oral and nasal cavity is possible.
Development 7-8 weeks and completes around the 3rd
month of gestation.
39

40.  3 outgrowths appear one
nasal septum and two palatine
shelves.
 They converge and fuse in
the midline.
 Displacement of tongue from
between the palatine shelves by
the growth pattern of the head is
a contributing factor closure of
palate
40

41. Meckels cartilage forms the lower jaw in primitive
vertebrates.
 In humans, Meckel’s cartilage has a close positional
relationship to the developing mandible but makes no
contribution to it.
 At 6 weeks of development this cartilage extends as a
solid hyaline cartilaginous rod, surrounded by a
fibrocellular capsule, from the developing ear to the
midline of the fused mandibular processes.
41

42. The two cartilages of each side are separated in the
midline by a thin line of mesenchyme
 During 6th week; a condensation of mesenchyme
occurs in the angle formed by the division of inferior
alveolar nerve
At 7th weeks; intramembranous ossification begins in
this codensation forming the first bone of the mandible.
42

43. 43

44.  Rapid spread of ossification
posteriorly into the
mesenchyme of the 1st arch.
 Spread of mandibular
ossification away from meckels
cartilage at the lingula.
44

45. Skull can be divided into 3 components:
The cranial vault
The cranial base
The face
45

46. 46
The human skull consists of three components:
(1) the membranous neurocranium, which constitutes
the flat bones of the skull,
(2) the cartilaginous neurocranium or chondrocranium
which forms the majority of the skull base, and
(3) the viscerocranium or facial skeleton.

47. 47
DEVELOPMENT OF BRAIN
The brain begins as three primary
vesicles :
1.prosencephalon – forebrain
2.mesencephalon – midbrain
3.rhombencephalon – hindbrain
Later the brain divides into
five secondary vesicles.

48. 48

49.  Region of eye is 1st seen as ectodermal thickenings, lens
placode, which appears lateral & cranial to the nasal
placode.
 Sinks below the surface & cut off from surface ectoderm.
49

50.  Developing eyeball produces a
bulging.
 Bulgings are at first seen
laterally & lie in the angles
between the maxillary& lateral
nasal processes.
 After narrowing of the
frontonasal process they lie
forward.
50

51.  6 auricular hillocks-forms primordia of the auricle around
the 1st pharyngeal groove(3 on each side) and primordium
of external acoustic meatus.
 Initially the external ears are in the neck region
 later they ascend to the side of the head
51

52. 52

53. Primary epithelial band is a band of epithelium that
has invaded underlying ectomesenchyme along each of
the horseshoe shaped future dental arches.
 At 7th week the PE band divides into Dental lamina
and vestibular lamina.
 The dental lamina shows a series of local
thickenings- enamel organ.
53

54. 54

55. The dental lamina is established in the sixth week of
intrauterine life.
The dental lamina serves as primordium of the
ectodermal position of the deciduous teeth.
 Permanent molars arise directly from a distal
extension of the dental lamina.
55

56. Genes expressed during tooth development
 Lef – lymphoid enhancer- binding factor (TF)
 Pax – paired box homeotic gene
 Fgf – fibroblast growth factor
 Bmp – bone morphogenetic proteins
 Barx – BarH1 homologue
56

57.  Develops at about 4 weeks.
Local proliferation gives rise to a
number of swellings in the floor
of the mouth.
 2 lateral lingual swellings
enlarge and merge with each
other and the tuberculam impair
to form a large mass, from which
anterior 2/3rd of the tongue is
formed.
57

58.  Root of the tongue arises from a
large midline swelling developed
from the mesenchyme of the 2nd
3rd & 4th arches.
 Swelling consists of copula and
large hypobranchial eminence. As
tongue develops, hypobranchial
eminence overgrows the copula.
 Posterior part of the fourth arch
marks the development of the
epiglottis.
58

59.  The salivary glands develop as outgrowths of the
buccal epithelium. The outgrowths are at first solid and
are later canalized.
 They branch repeatedly to form the duct system. The
terminal part of the duct system develop into secretory
acini.
59

60. 60

61. 61

62. 62
Congenital
auricular sinuses
PHARYNGEALARCH DEFECTS

63.  Preauricular sinus is a congenital anomaly that occurs
because of a malformation during the merging of first
and second branchial clefts, which form the ear in the
course of embryonic development.
 Although it is usually non-symptomatic, it can rarely
be seen together with recurrent swelling and discharge,
and inflammatory infections.
63
PHARYNGEALARCH DEFECTS

64.  Most of the preauricular sinuses do not show
symtptoms for a life time and do not need a treatment.
 Preauricular sinus infection develops in few patients,
and after the symptoms are observed, the sinus tract is
clearly marked out and the patient is advised for a
surgical excision.
 Inadequate excisions often lead to recurrences
64
PHARYNGEALARCH DEFECTS

65. 65
Cervical vestiges

66. Internal branchial fistulas :
It is very rare and in this the cervical sinus is connected to the
lumen of the pharynx by a small canal which usually opens in
the tonsillar region.
66
PHARYNGEALARCH DEFECTS

67. 67

68. MICROTIA & ATRESIA
68

69. HEMI-FACIAL MICROSOMIA (HFM):
Hemifacial microsomia is known by a variety of other
names, including craniofacial microsomia, first and
second pharyngeal arch syndrome, Goldenhar syndrome,
and lateral facial dysplasia.
69
PHARYNGEALARCH DEFECTS

70. It occurs when soft tissue and bone from the
pharyngeal arches on one side of a child's face fail
to develop fully
70
PHARYNGEALARCH DEFECTS

71.  Either one-sided (unilateral) or two-sided (bilateral)
underdevelopment of the eye, cheekbone, lower jaw,
facial nerve and muscles.
 There may be hearing loss caused by the
underdevelopment of the middle ear. The soft palate
may move to the unaffected side because of muscle
weakness on the affected side.
71
PHARYNGEALARCH DEFECTS

72.  The tongue may be small with weakness on the
affected side.
 The facial muscles is weak on the affected side
or, rarely, on both sides.
72
PHARYNGEALARCH DEFECTS

73. FIRST ARCH SYNDROME-
PIERRE ROBIN’S SYNDROME
73

74. 74
ARHINIA
Bilateral absence of nasal placodes
BOSMAARHINIA MICROPHTHALMIA
SYNDROME(BAMS)

75. 75
MIDLINE
NASAL SINUS
PROBOSCIS
LATERALIS
ANOMALIES OF NOSE

76. 76
HALF NOSE
Unilateral absence of
nasal placode.
DOUBLE
NOSE
ANOMALIES OF NOSE

77. 77
BILATERAL
ANOPHTHALMIA
CONGENITAL
APHAKIA

78. 78
CYCLOPIA
CONGENITAL
CATARACTS
ANOMALIES OF EYE

79. 79
BLUE
SCLERA
COLOBOMA
ANOMALIES OF EYE

80. 80

81. 81

82. CLEFT PALATE-INCOMPLETE
82

83. 83
FACIAL
CLEFT

84.  Macroglossia, microglossia, aglossia
 Bifid tongue
 Ankyloglossia
 Geographical tongue
 Persistence of tuberculum impar
 Thyroid tissue within the muscles
 Remnants of thyroglossal duct
 Fissured tongue
84

85. 85
AGLOSSIA MACROGLOSSIA MICROGLOSSIA
ANOMALIES OF TONGUE

86. 86
FISSURED TONGUE TONGUE TIE
ANOMALIES OF TONGUE

87. 87
BIFID TONGUE GEOGRAPHIC TONGUE
MEDIAN RHOMBOID
GLOSSITIS
ANOMALIES OF TONGUE

88. One or more teeth are absent.
 Supernumerary teeth.
 Individual tooth abnormality.
 Gemination.
 Malocclusion.
 Precocious eruption.
 Delayed eruption
 Improper formation of enamel and dentin.
88

89. 89
SUPERNUMERARY TEETH PARTIAL ANODONTIA

90. 90
GEMINATION FUSION

91. 91
AMELOGENESIS
IMPERFECTA
DENTINOGENESIS
IMPERFECTA

92. 92
Van der woude syndrome
Achondroplasia
Apert Syndrome
Stickler Syndrome
Cleidocranial Dysplasia
Ectodermal Dysplasia
Fetal alcoholic syndrome
Treacher Collins Syndrome
Hemifacial Microsomia
( Goldenhar Syndrome)
cretinism
Down's syndrome
Hunter's syndrome
San Syndrome

93. 93
Prevention targets particular risk factors to reduce or
minimize the occurrence of congenital anomalies.
PRIMARY
PREVENTION
• Avoiding the
consanguineous
marriages.
• Maternal
nutrition,
particularly prior
conception, of
using folic acid
supplements and
fortified foods.
SECONDARY
PREVENTION
• Early detection
of a congenital
anomaly
followed by
successful
medical/surgical
intervention
(antenatal
screening)
TERTIARY
PREVENTION
• Surgical
correction of
congenital
anomaly after
which the
individual has
complete recover
without residual
defects or
minimal defects

94. 94
Smile Train is a charity
providing corrective
surgery for children with
cleft lips and palates since
1999.

95.  The knowledge of development of face and other
structures in human being is very important for health
professionals.
 If they are aware of the normal developments, then
only they can identify abnormal developments which
needs intervention at the early stage of child birth,
otherwise the child have to suffer throughout the life
with the defects which leads to disabilities
95

96. REFERENCES:
 Inderbir Singh - human embryology- 9th edition. New
Delhi; Macmillan Publishers India 2013
 Keith L. Moore, Persuad T.V.N., Mark G. Torchia Before
we are born-Essentials of embryology and birth defects, 8th
edition. Philadelphia; Elseviers Saunders 2013
 Langman’s Medical Embryology-11th edition.
 Romanes G.J. Cunningham’s Manual of Practical Anatomy
Volume 3 Head, Neck and Brain, 15th edition. NewYork ;
Oxford University Press 2006.
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