Embryology is necessary to understand the growth of various anatomical structures pertinent to orthodontics and will help understand the anomalies associated with its maldevelopment.

1. EMBRYOLOGY
IN ORTHODONTICS
By,
Dr. Miliya Parveen

2. Contents :
• Introduction
• Weeks 1 And 2 Of Development
• Week 3 Of Development (Trilaminar Disk Stage )
• Week 4 Of Development (Folding Of The Embryo)
• Development Of The Head And Neck -
• Pharyngeal (Branchial) Apparatus
• Development Of The Face
• Development Of The Palate
• Development Of The Nose
• Development Of The Maxilla
• Development Of The Mandible
• Development Of The T0ngue
• Development Of The Skull
• Defects And Syndromes Of The First And Second Pharyngeal Arches

3. Introduction:
• Embryology is the study of formation and development of the embryo
(foetus) from the moment of inception up to the time of birth.
• Additionally, embryology
encompasses the study
of congenital disorders that
occur before birth.

4. • Prenatal human development is traditionally divided into:
I. The pre-implantation period - fertilization to 2nd week of
development
II. The embryonic period - 2nd week through 8th week
III. The foetal period - from 9th week to term.

5. Weeks 1 and 2 of Development:
Spermatozoon
fertilizes an
oocyte forming
in oviduct
Cleavage
Blastomeres
Adhere
A fluid-filled space
called the blastocyst
cavity or blastocele

6.  Six days after fertilization, two distinct cell types comprise the
blastocyst:
 Two important events occur in the blastocyst at the beginning of second
week :
I. The blastocyst adheres to the surface of the endometrium and
implantation begins.
II. The inner cell mass forms a bilaminar disk - bilaminar disk
stage.
Blastocyst
Trophoblast
Forms embryonic part of
the placenta and other
structures
Embryoblast Embryo

7. • After implantation,
Blastocyst
Trophoblast
Cytotrophoblast
Synctiotrophoblast
Inner cell mass
Epiblast
Hypoblast

8. • The amniotic cavity is located between the epiblast and
cytotrophoblast, and the blastocyst cavity will become the
primitive yolk sac.
• By the end of the second week of development the hypoblast will
form a localized area of thickening called the prochordal plate at
the cranial end of the bilaminar disk.

9. Week 3 of Development (Trilaminar disk stage ):
• Gastrulation begins with formation of
the primitive streak- a narrow trough with
slightly bulging sides that develops in the
midline of the epiblast toward the caudal
end.
Clinical Note:
If remnants of the primitive streak
persist in the sacrococcygeal region, it
may proliferate into sacrococcygeal
teratomas. This is the most common
tumour seen in newborns.

10. • During gastrulation, the epiblast cells migrate through the
primitive streak and forms three embryonic germ layers -
I. The ectoderm – forms the exoskeleton
II. The endoderm – develops into organs
III. The mesoderm– forms the inner lining of the organs
Clinical Note:
Weeks 4 through 8 are
especially important because
the tissues and organ systems
are developing rapidly from the
original three germ layers.
Exposure of embryos to
teratogens, such as viruses and
drugs, during these weeks may
result in congenital
abnormalities.

11. • Another important structure that forms early in the third week is the
notochord - by the cells in the primitive node and pits which proliferate
till the prechordial plate, the future buccopharyngeal membrane. The
notochord represents the early midline axis of the embryo, and the axial
skeleton forms around it.

12. • The ECTODERMAL GERM LAYER generally forms structures that
maintain contact with the outer environment among which, formation of
the neuroectoderm and the neural crest are of particular importance i.e
neurulation.
Clinical Note:
Very high ethanol levels during this period causes deficiency of the midline
tissue of the neural plate resulting in maxillary and mandibular deficiency,
known as fetal alcohol syndrome.

13. • Neurulation is the process of development of the neural plate,
neuroectoderm, and folding to produce the neural tube. During the
third week, it is the notochord that induces the overlying ectoderm to
thicken and differentiate into the neural plate.

14. • The neural tube is the primordium of
the central nervous system. The anterior
region of the neural tube enlarges to
form the forebrain, midbrain, and
hindbrain and eight bulges called
rhombomeres develop in the hindbrain.

15. • Neural crest cells arise from the neural folds and migrate
throughout the body but those migrating from the rhombomeres
express the homeobox (HOX) genes.
Clinical Note:
HOX genes produce transcription factors that bind to the DNA of other genes and
regulate gene expression. Homeobox genes are important in determining the
identity and spatial arrangements of body regions, and they help determine the
pattern and position of structures developing within the pharyngeal arches.
Mutations of homeobox genes have been associated with congenital craniofacial
anomalies such as Waardenburg's syndrome and one form of Holoprosencephaly.

16. • The MESODERM on either
side of the notochord thickens to
form longitudinal columns of
tissue called the paraxial
mesoderm which segments into
paired blocks of tissue called
somites.
• The most cranial somites,
called somitomeres, are only
partially segmented structures.
There are seven somitomeres
approximately in register with
the pharyngeal arches.

17. • The somite cells develop into different components –
I. Superficial somite cells become the
dermatome and form the dermis.
II. Deeper somite cells become the myotome
and develop into most of the skeletal
muscles of the trunk and limbs.
III. Some somite cells migrate to the region
around the notochord, become the
sclerotome and form the axial
skeleton (cartilage and bone components)
• Derivatives of ENDODERM include components of the
gastrointestinal, respiratory, urinary, and endocrine systems and the ear.
Clinical Note:
Since the somites
appear in a specified
periodicity, the age of
embryo can be
determined by
counting the number
of somites.

18. • Beginning in the fourth week of development the flat trilaminar
embryonic disk folds in two planes to form a more typical-appearing,
cylindric, C-shaped embryo.
• Folding in the cranial-caudal plane is mainly due to rapid longitudinal
growth of the central nervous system and growth of somites causes
lateral-medial folding.
Week 4 of Development (Folding of the Embryo):

19. • Folding brings the endodermal-lined yolk sac into the embryo and
creates the primordial gut: the foregut, midgut, and hindgut.
• The buccopharyngeal membrane which separates the foregut and the
primitive oral cavity called the stomodeum, breaks down at the end of
the third week, allowing continuity between the foregut and
stomodeum.

20. • The pharyngeal arches begin their development during the fourth week
as a result of migration of neural crest cells into the head and neck region
and gives rise to a significant number of structures of the head and neck.
• Four distinct pairs of pharyngeal arches are
seen. Arches V and VI are poorly developed
in humans.
• The fifth arch completely regresses
and does not give rise to structures. Arch IV
is the result of fusion of arches IV and VI.
DEVELOPMENT OF THE HEAD AND NECK
Pharyngeal (Branchial) Apparatus

21. I. Pharyngeal grooves or clefts
separate the arches on the external
surface of the embryo by fissures.
II. Pharyngeal pouches partially
separate the arches on the internal
aspect.
III. The pharyngeal membranes
represent the tissue interposed
between pouches and clefts and
connect adjacent arches.
• Pharyngeal arches, grooves, pouches, and membranes are important because
they give rise to head and neck structures.

22. • Each pharyngeal arch has -
I. A specific cartilage that forms the
skeleton of the arch
I. Muscular component
II. Vascular component
III. A nerve that supplies the muscles
IV. Mucosa derived from that arch
• The pharyngeal arches play the major role in the formation of the face,
oral cavity and teeth, nasal cavities, pharynx, larynx, and neck.

23. • Derivatives of the PHARYNGEAL ARCHES are as follows -
Mandibular
Hyoid

25. • Arch I called the mandibular arch, is a major contributor to development of
the face.
• This pair of arches has distinct maxillary and mandibular processes, or
prominences.
• Neural crest mesenchyme in the maxillary process undergoes
intramembranous ossification to give rise to the zygomatic bone, the maxilla,
and the squamous portion of the temporal bone.

26. • The cartilage of the first arch is Meckel's cartilage and its derivatives are –
Dorsal end Ossifies
Middle ear ossicles
(malleus and incus)
Middle portion
(Perichondrium)
Fibrous tissue Sphenomandibular
ligament
Ventral portion Horseshoe - shaped Mandible
Mesenchymal tissue
(lateral to cartilage)
Intramembraneous
ossification
Mandible

27. • Arch II is called the hyoid arch because of its contribution to development
of the hyoid bone, specifically, the lesser horn and the superior portion of the
body.
• The cartilage of arch II is known as Reichert's cartilage. Its derivatives are -
Dorsal end Ossifies
Middle ear ossicle
(stapes) and the
styloid process
Perichondrium Fibrous tissue
Stylohyoid
ligament

28. • Derivatives of the PHARYNGEAL POUCHES, GROOVES AND
MEMBRANE -

29. DEVELOPMENT OF THE FACE
• Development of the face occurs primarily between weeks 4 and 8.
• Facial development results mainly
from enlargement and movement
of the frontonasal prominence
and four prominences from
pharyngeal arch I, the paired
maxillary and mandibular
prominences.
• These structures surround
the stomodeum.

30. • Mesoderm covering the developing
forebrain proliferates and forms a
downward projection that overlaps the
upper part of the stomodeum forming
the frontonasal process.
• One of the first events in formation of
facial structures is fusion of the medial
ends of the mandibular prominences in
the midline to form the chin and lower
lip.

31. • During the 5th week, the region of the eye
is first seen as an ectodermal thickening on
the ventrolateral side of the developing
forebrain – lens placode.
• Areas of thickening derived from a
specialized surface ectoderm overlying the
developing hindbrain – octic placode. It
depresses below the ectoderm to form the
otic pit which then becomes rounded to
form the otic vesicle separated from
surface ectoderm.

32. • In the inferior and lateral portion of the frontonasal prominence, bilateral
localized areas of surface ectoderm thicken to form nasal placodes.
• The mesenchyme along the periphery of the nasal placodes proliferates
and forms horseshoe-shaped ridges called the medial nasal prominences and
lateral nasal prominences.
• The center of the placode becomes thinner, eventually leading to loss of
ectoderm and formation of nasal pits. The nasal pits are the precursors of the
nostrils and nasal cavities.

33. • Mesenchymal connective tissue in the maxillary prominences
proliferates. The result is that the maxillary prominences become
larger and move medially toward each other and toward the medial
nasal prominences.

34. • The medial nasal prominences
move toward each other, fuse in
the midline forming the
intermaxillary segment which
gives rise to the philtrum, four
incisor teeth, alveolar bone and
gingiva, and primary palate.
• The nasolacrimal ducts form
at the line of fusion between
lateral nasal prominences and
maxillary prominences.

35. DEVELOPMENT OF THE PALATE
• The palate develops from week 6
till 12. The most critical period
being the end of the 6th week to
the beginning of the 9th week.
• The entire palate develops from
two structures - the primary palate
(premaxilla) and the secondary
palate.

36. • The primary palate is the triangular shaped part of the palate anterior
to the incisive foramen, which arises from the fusion of the two medial
nasal prominences.
• The secondary palate arises from paired lateral palatine shelves of the
maxilla which are oriented in a superior-inferior plane with the tongue
interposed.
• Later, the lateral palatine shelves become elongated and the tongue
becomes relatively smaller and moves inferiorly.

37. • The incisive foramen is
present at the junction of
the primary palate and the
lateral palatine shelves. The
lateral palatine shelves also
fuse with the primary
palate and the nasal
septum.
• The shelves become oriented horizontally and fuse in the midline.
The median palatine raphe is a clinical remnant of fusion between
the palatine shelves.

38. DEVELOPMENT OF THE NOSE
• Begins with the formation of nasal placodes.
• The nose is a complex of contributions from the frontonasal
process (the deeper part forms the nasal septum), the merged medial
nasal prominences (the median ridge and tip) and the lateral nasal
prominences (the alae).

39. DEVELOPMENT OF THE MAXILLA
• Maxilla arises from ossification centers in the mesenchyme of the
maxillary process of the 1st arch
• The primary intramembranous ossification center appears for each
maxilla in the 7th week, at the termination of infra-orbital nerve just above
the canine tooth dental lamina.
• Secondary ossification centers for maxilla are zygomatic, orbitonasal,
nasopalatine & intermaxillary.
• The two maxillary ossification centers generate the premaxillary region.

40. • As a result of bone deposition - a bony trough forms for the infraorbital
nerve
• From this trough a bony downward extension forms the lateral alveolar
plate for the maxillary tooth germs

41. • Ossification spreads in to the palatine process to form hard palate.
• The medial alveolar plate develops from the junction of the palatal
process & main body of the forming maxilla.
• This plate together with its lateral counterpart forms a trough of bone
around the maxillary tooth germs, which eventually become enclosed
in bony crypts .

42. • Derived from ossification of an osteogenic membrane at 36 to 38 days of
development
• At 6th week, a single ossification center for each half of mandible arises at
bifurcation of inferior alveolar nerve.
DEVELOPMENT OF THE MANDIBLE

43. • Ossification spreads from primary center below and around the inferior
alveolar nerve and its incisive branch and upwards to form a trough for
developing teeth.
• Ossification spreads dorsally and ventrally forms body and ramus of
mandible .
• Meckels cartilage becomes surrounded and invaded by bone.

44. • Ossification stops dorsally at site that will
later become mandibular lingula from
where Meckel’s cartilage continuous into
middle ear and develops into the auditory
aussicles ; malleus and incus.
• Between 10th -14th weeks, secondary
accessory cartilages appear to form –
1. Condylar cartilage
2. Coronoid cartilage
3. Symphyseal cartilage

45. • Condylar secondary cartilage develops during 10th
week i.u. as cone shaped in ramal region. This is
primordium of future condyle.
• By 14th week first evidence of endochondral bone
appears in condylar region. Much of cone shaped
cartilage is replaced with bone by middle of fetal life;
but its upper end persists in adulthood acting as both a
growth cartilage and an articular cartilage.

46. • The condylar cartilage -
1. Serves as a growth site
2. Brings changes in the mandibular position and
form
3. Growth increases during puberty
4. Peak 12 – 14 years
5. Ceases by 20 years
• The secondary coronoid cartilage ( 4th month of iu life) -
1. Develops within temporalis muscle
2. Incorporated into intramembranous bone of ramus
3. Disappear before birth

47. • In mental region on either side of the Symphysis, one or two small
symphysial cartilages appear and ossify in the 7th month of i.u. to form a
variable number of mental ossicles in the fibrous tissue of the symphysis.
• Thus mandible is membrane
bone developed in relation to
the nerve of the 1st arch &
almost independent of Meckel’s
cartilage.
• The mandible has neural,
alveolar & muscular elements
& its growth is assisted by the
development of secondary
cartilages.

48. DEVELOPMENT OF THE TONGUE
• The mucosa of the body of the
tongue or anterior two thirds of
the tongue develops from the first
pharyngeal arch, whereas the
mucosa of the base of the tongue
or posterior third develops from
arch III.
• The skeletal muscle of the tongue develops from myoblasts that migrate
into the tongue from occipital somites. The tongue begins its development
near the end of the fourth week as a midline enlargement near the
foramen cecum.

49. • The enlargement is called the tuberculum impar. Two lateral lingual
swellings form adjacent to the tuberculum impar.
• All three structures are formed by
proliferation of first arch
mesenchyme.
• The lateral lingual swellings
rapidly enlarge, fuse with one
another, and overgrow the
tuberculum impar, all of which form
the body of the tongue.

50. • The posterior third, or base, of the tongue develops from the
hypobranchial eminence, which is a midline swelling caudal to
the foramen cecum. The hypobranchial eminence is comprised
primarily of mesenchyme from arch III.

51. • The copula is a midline enlargement derived from arch II. The
hypobranchial eminence overgrows the copula and fuses with the
tuberculum impar and lateral lingual swellings after which the copula
disappears. Thus the base of the tongue is derived from the third pharyngeal
arch.
• The line of demarcation
between the body and
base is called the
terminal sulcus, and the
foramen cecum is found
in the midline of this
structure.

52. Tongue
Anterior
two-thirds
Tuberculum
impar
Arch I
Two
lateral
swellings
Arch I
Posterior
one third
Hypobranchial
eminence
Arch III
Copula
Arch II

53. Muscles of the tongue

54. Vascular supply of the tongue

55. Nerve supply of the tongue

56. Lymphatic drainage of the tongue

57. • The skull forms from mesenchymal connective tissue around the
developing brain. The development of the skull is considered in two
components -
DEVELOPMENT OF THE SKULL
I. Neurocranium (the calvaria
and base of the skull) derived
mainly from occipital somites
II. Viscerocranium (the skeleton
of the face and associated
structures) derived from
neural crest ectoderm

58. • Each component has some structures that form by endochondral
ossification (cartilaginous component) and other structures that form
by intramembranous ossification (membranous component).
• The cartilaginous NEUROCRANIUM (chondrocranium) consists of
several cartilages that fuse and undergo endochondral ossification to
give rise to the base of the skull.
• The membranous neurocranium gives rise to the flat bones of the
calvaria, including the superior portion of the frontal, parietal, and
occipital bones.

59. • The cartilage junctions between two bones are called synchondroses.
• New cartilage cells continually form in the center of the
synchondrosis, move peripherally, and then undergo endochondral
ossification along the lateral margins.

60. • Sutures, also called syndesmoses, are fibrous joints comprised of sheets
of dense connective tissue that separate the bones of the calvaria while
fontanelles are regions of dense connective tissue where sutures come
together.
• Sutures and fontanelles ossify at variable times after birth.

61. • These bones form by intramembranous
ossification except for the mandibular
condyle and the midline of the chin.
•The squamous temporal bones later
become part of the neurocranium.
• The cartilaginous VISCEROCRANIUM includes the middle ear
ossicles, the styloid process of the temporal bone, the hyoid bone,
and the laryngeal cartilages.
• The membranous viscerocranium includes the maxilla, zygomatic
bones, the squamous temporal bones, and the mandible.

62. Defects and Syndromes of the
First and Second Pharyngeal Arches
ISOLATED DEFECTS -
1. Facial clefting:
• Facial clefting, cleft lip (CL) with or
without cleft palate (CP) is the most
common congenital craniofacial malformation.
Incidence of OFC in India is 1 in 700 live births.
•Facial clefting has a major clinical impact, requiring surgical, dental,
orthodontic, speech, hearing, and psychological management
throughout childhood.

63. • Genetic factors include genes
associated with syndromic clefts
and non- syndromic clefts.
 Syndromic Clefts
1. Treacher Collins Syndrome
2. Vander Woude Syndrome
3. Sticklers Syndrome
4. Patau Syndrome
• Environmental Factors include:
1. Maternal smoking
2. Maternal alcohol abuse
3. Pesticide exposure
4. Insufficient diet and nutritional
uptake (especially retinoids)
5. Certain drugs:
Anticonvulsants-Valium,
Methotextrate
6. Rubella virus infection and
syphilis infection
7. Radiotherapy
• The etiology of CL/P is mostly unknown, but both genetic and
environmental factors play a role.

64. • Oblique facial clefts are very rare
congenital deformities.
• Non fusion of the lateral nasal
process and the maxillary process
gives rise to a cleft running from the
medial angle of the eye to the corner of
the mouth.
• The nasolacrimal duct is not formed.

65. • Failure of fusion between any of the facial structures results in a
cleft, which may be unilateral or bilateral.
 Upper cleft lip - non fusion of 2 maxillary process with
each medial and lateral nasal process
 Lower cleft lip - non fusion of 2 mandibular process
 Cleft palate - non fusion of 2 palatine shelves with each
other

66.  Davies and Ritchie Classification (1992) - Morphological classification
based on location of the cleft to alveolar process
I. GROUP I- Prealveolar Clefts: They are clefts involving only the lip
 Unilateral
 Bilateral
 Median
II. GROUP II- Postalveolar Clefts: Clefts involve various degree of hard
and soft palate and may extend upto alveolus. ( Submucous clefts are
also included)
III. GROUP III- Alveolar Clefts: Complete Clefts involving Palate, Alveolar
ridge and the lip. Subdivided as:
 Unilateral
 Bilateral
 Median
• Classification:

67.  Veau’s Classification (1931) -
Classified into 4 groups
Group 1- cleft involving soft palate
only
Group 2- cleft of hard and soft
palate extending upto the incisive
foramen
Group 3- complete U/L cleft
involving the soft palate, hard palate
alveolar ridge and lip
Group 4- Complete B/L clefts
involving the soft palate, lip, hard
palate and alveolar ridge

68.  Fogh Andersons’s Classification (1942) –
Group 1- Cleft of lip
SINGLE- Unilateral
DOUBLE- Bilateral
Group 2- Cleft lip and Palate
SINGLE- Unilateral
DOUBLE- Bilateral
Group 3- Cleft of palate extending upto the incisive foramen

69.  Kernahan’s and Stark’s Classification (1958) -
Clefts of Primary palate:
 Unilateral (R/L)
• Complete
• Incomplete
 Bilateral
• Complete
• Incomplete
 Median
• Complete ( Pre-maxilla absent)
• Incomplete (Pre maxilla rudimentary)

70.  American Cleft Palate Association’s Classification (1962) –
1. Clefts of the prepalate (cleft of lip and embryologic primary palate)
a. Cleft lip (cheiloschisis)
b. Cleft alveolus (alveoloschisis)
c. Cleft lip, alveolus, and primary palate (cheiloalveoloschisis)
2. Clefts of the palate (cleft of the embryologic secondary palate)
a. Cleft of the hard palate (uranoschisis)
b. Cleft of the soft palate (staphyloschisis or veloschisis)
c. Cleft of the hard and soft palate (uranostaphyloschisis)
3. Clefts of the prepalate and palate (alveolocheilopalatoschisis)
4. Facial clefts other than prepalatal and palatal
a. Cleft of the mandibular process
b. Naso-ocular clefts
c. Oro-ocular clefts
d. Oroaural clefts

71. The classification comprises a
stripped ‘Y’ having number blocks.
Block 1,4- Lip
Block 2,5- Alveolus
Block 3,6- Hard palate anterior
to incisive foramina
Block 7,8- Hard palate
Block 9 - Soft palate
 Kernahan’s Stripped ‘Y’ Classification (1971) -

72. Millards Modification of Stripped ‘Y’ Classification (1976)

73. 2. Auricular Atresia:
• Auricular atresia occurs along a spectrum from an isolated malformed
auricle to an absent EAC with severe inner, middle, and external ear
defects.
• Middle ear defects can be subtle or severe and include absent or
maldevelopment of any of the ossicles, with alteration of other structures
of common embryologic origin.
• Auricular atresia can produce a number of problems for patients,
including audiologic, cosmetic, and other associated clinical problems.
• EAC atresia has been described as part of various syndromes including
Treacher Collins Syndrome, Pierre Robin Syndrome, Goldenhar
syndrome, etc.

74. 3. Micrognathia :
• Micrognathia is a frequently encountered
facial abnormality in which the mandible is
hypoplastic.
• Milder forms of micrognathia are common in
infants and typically resolve with growth of the
mandible.
• In syndromes involving micrognathia, the
oromandibular abnormalities often require the
most intensive medical intervention.

75. • In severe cases of mandibular
hypoplasia, glossoptosis may lead to
upper respiratory tract obstruction.
• Glossoptosis is also associated with
snoring, apnea, and sleep disturbance.
• In less severe cases, malocclusion may
lead to masticatory abnormalities that
require orthodontic treatment or
orthognathic surgery.
• Speech therapy may also be required to
treat the articulation defects that may be
seen in some patients.

76. SYNDROMES -
1. Pierre Robin Syndrome :
• The genetic causes for some of the isolated cases may
include mutations or deletions of parts of the DNA in chromosome 17.
• This gene provides instructions for making a protein that plays an
important role in the formation of many different tissues and organs during
embryonic development.
• Pierre Robin sequence (PRS) is
classically described as a triad of
micrognathia, glossoptosis, and
airway obstruction.

77. 1. Unusually small mandibles (micrognathia)
2. Posterior displacement or retraction of the tongue (glossoptosis)
3. Upper airway obstruction.
4. Cleft palate
5. Bimaxillary retrognathia
6. Symmetric hypoplasia of the mandible
7. Associated condylar and coronoid hypoplasia.

78. 2. Treacher Collins Syndrome :
• Mandibulofacial dyostosis
• Autosomal dominant
• It occurs in approximately 1 in 50,000 births.
• General cranioskeletal hypoplasia occurs due
to generation of insufficient neural crest cells.
• Most of the features of TCS are symmetrical.

79. Facial bones:
1. Hypoplasia of mandible and zygomatic complex
2. Zygomatic arches may be completely absent
3. Micrognathia and
4. Maxillary narrowing or overprojection.
Ear:
1. Absent EAC
2. Middle ear malformations
3. Pinna deformities
4. Hearing loss
Nose: Broad or protruding.

80. Eye:
1. Deformities of external eye
2. Notches in the lower eyelids (coloboma)
3. Partial or complete absence of eyelashes on the
lower lid
4. Downward slanting of the palpebral fissures
5. Drooping of upper and lower eyelids
6. Narrowing of the tear ducts.
Dental:
1. Cleft palate
2. Anterior open bite
3. Malocclusion with severe spacing, malpositioned
or reduced number of teeth
4. Palate is high, arched

81. • Autosomal dominant syndrome, characterized by flat midface with a
depressed nasal bridge and short nose.
• The clinical picture is highly variable varying from dwarfism/marfanoid
habitus to phenotypically healthy individuals.
• So the syndrome is often broken into 3 types based on mutations in
different genes.
3. Stickler Syndrome :

82. Ocular:
1. Retinal detachment
2. High nonprogressive myopia
3. Vitreoretinal degeneration
4. Cataracts
5. Blindness
Auditory:
1. Defective auditory ossicles
2. Hearing loss.
Dental:
1. Cleft palate
2. Micrognathia
3. High arched palate
Skeletal:
1. Enlarged joints
2. Epiphyseal changes
3. Mild platyspondyly
4. Ligamentous laxity and stiffness.
5. Osteoarthritis
6. Abnormal curvature of the spine

83. 3. Goldenhar Syndrome :
• Goldenhar syndrome (GS) or oculoauriculovertebral dysplasia or
hemifacial microsomia.
• Clinical manifestations include craniofacial, vertebral , cardiac, renal,
and central nervous system anomalies.
• Caused by development defects of the first and second brachial arches.

84. • Aural defects:
1. Preauricular tags
2. Anotia
3. Microtia
4. Hearing loss
• Vertebral abnormalities:
1. Scoliosis
2. Hemivertebrae
3. Cervical fusion
• Ocular anomalies:
1. Microphthalmia
2. Anophthalmia
3. Epibulbar dermoid tumors
4. Eyelid colobomas
• Facial involvement:
1. Unilateral, marked asymmetry
2. Hemifacial microsomia
3. Mandibular hypoplasia
4. Cleft lip and palate

85. • The increasing sophistication of intrauterine imaging techniques is
revealing ever-earlier stages of fetal formation and malformation that may
allow diagnosis and possible treatment.
• The advantage of an intimate knowledge of embryology at different stages
of development has immense potential in translating this information into
clinical decision-making in the treatment of abnormal fetuses and
subsequently diseased infants.
• The basis for understanding the mechanisms underlying normal and
abnormal development is inherent in embryological education and thus
provides insights into the organization of adult anatomy and its aberrations
recognized as syndromes.
Conclusion:

86. • Orthodontics: Diagnosis of and Management of Malocclusion and Dentofacial
Deformities, Om Prakash Kharbanda, 2nd edition
•Essentials of facial growth – Enlow
• Human embryology, Inderbir Singh, 7th edition
• Craniofacial Growth and development, Sridhar Premkumar
• Textbook of Orthodontics, Samir E. Bishra
• Johnson, J. M., Moonis, G., Green, G. E., Carmody, R., & Burbank, H. N.
(2010). Syndromes of the First and Second Branchial Arches, Part 2: Syndromes.
American Journal of Neuroradiology, 32(2), 230–237.
• Trainor PA, Dixon J, Dixon MJ. Treacher Collins syndrome: etiology, pathogenesis
and prevention. Eur J Hum Genet. 2009;17(3):275–283.
• Gangopadhyay, N., Mendonca, D., & Woo, A. (2012). Pierre Robin Sequence.
Seminars in Plastic Surgery, 26(02), 076–082
• Martelli H Jr, Miranda RT, Fernandes CM, et al. Goldenhar syndrome: clinical
features with orofacial emphasis. J Appl Oral Sci. 2010;18(6):646–649.
Refernces: