EMBRYOLOGY GROWTH & DEVELOPMENT OF CRANIUM & BASE OF CRANIUM & ITS SIGNIFICANCE IN ORTHODONTICS

1. GROWTH & DEVELOPMENT
OF CRANIUM & BASE OF
CRANIUM
PRESENTED BY:
DR SHRESTHA
MAJUMDAR
MDS 1ST YEAR

2. CONTENTS :
• Introduction
• Prenatal craniofacial growth
• Developmental anomalies
• Prenatal and postnatal growth of cranium
• Cranial base and cranial base angulation
• Timing of growth in width ,length and height
• Developmental anomalies of Cranium
• Clinical Significance

3. INTRODUCTION :
• The organization and complexity of growth and
development is clearly evident in the changes that
take place in the head and face.
• Human facial skeleton is unique; craniofacium is
formed of 22 bones, 8 cranial and 14 facial bones
inclusive of the mandible, the movable bone of face.

4. GROWTH :
• According to Todd "Growth is an increase in size."
• "The entire series of anatomic and physiologic changes taking
place between the beginning of prenatal life and the close of
senility" - Meredith .
• "Increase in size ,change in spatial proportion over time"-
Krogman.
• According to Proffit " Growth usually refers to an increase in size
or number.”
• Self multiplication of living tissues –J S Huxley.
• Any change in Morphology which is with in measurable

5. DEVELOPMENT :
•According to Todd "Development is progress
toward maturity.“
•Melvin Moss – Development can be considered
as a continuous of casually related events from
the fertilization of ovum onwards.

6. GROWTH AND DEVELOPMENT
CAN BE DIVIDED INTO :
Prenatal
period Postnatal
period

7. PRENATAL CRANIOFACIAL GROWTH
:
• Period of ovum - conception to 7-8days ovulation to
implantation.
• Period of embryo beginning of 2nd week till the 8th week.
-pre somite period : 8-20 days
-somite period : 21-31 days
-post somite period : 32-56 days
• Period of fetus 9th week to birth.

8. OVULATION &
FERTILIZATION:

9. CLEAVAGE & BLASTOCYST
FORMATION :

10. NEURAL TUBE
FORMATION :
• The process of development of the neural plate, neuroectoderm and
folding to produce the neural tube is called as neurulation.
• The ectoderm above the notochord is induced to form a thickening called
the neural plate.
• The midline of neural plate deepens to form a groove with elevated
margins on either side, the neural folds.
• The neural folds grow towards each other and fuse to form the neural
tube, which forms the central nervous system.

11. • Failure of neural crest cells to properly migrate to the
facial region leads to craniofacial anomalies, such as
Treacher Collins syndrome.
• The cranial neural crest gives rise to the:
❖ Majority of the head connective
and skeletal structures
❖ Nerves
❖ Pigment cells
❖ Odontoblasts

12. NEURAL TUBE DEFECTS :
• based on the presence or absence of exposed neural tube
OPEN CLOSE
D
Spina bifida
Anencephaly
Encephalocele
Lipomyelomeningo
cele

13. PHARYNGEAL ARCHES :
• Pharyngeal arches are rod-like thickenings of mesoderm present in
the wall of the foregut. They develop during 4thweek of IUL.
• At first there are six arches.
• The fifth arch disappears and only five remain.

14. Skeletal derivatives of pharyngeal arches
• The cartilage of first arch is called Meckel’s cartilage.
Derivatives are
Incus and malleus
Mandible
Maxilla
Zygomatic bone
Palatine bone
Temporal bone
Anterior ligament of the malleus
Sphenomandibular ligament

15. • Cartilage of second arch is Reichert’s
cartilage.
• Derivatives are
Stapes
Styloid process
Stylohyoid ligament
Lesser cornu of hyoid bone
Superior part of body of hyoid bone

16. • Cartilage of third arch
Greater cornu of hyoid bone
Lower part of the body of hyoid bone
• fourth and sixth arches
Cartilage of larynx

21. • After the formation of head fold, the developing brain and the
pericardium, two prominent swellings appear on the ventral aspect of
embryo separated by stomodeum.
• Development of face occurs primarily between 4th and 8th week of
gestation.
• Mesoderm covering the developing forebrain proliferates and overlaps
stomodeum to form frontonasal process.

22. • Mandibular arch which forms the lateral wall of stomatodeum gives
off a bud from its dorsal end called maxillary process.
• The ventromedial growth of this process is called the mandibular
process.

23. DEVELOPMENTAL
ANOMALIES

24. MANDIBULOFACIAL DYSOSTOSIS/ TREACHER
COLLINS SYNDROME/ FIRST ARCH SYNDROME
• This is a genetic condition
inherited as autosomal
dominant.
• The entire first arch may
remain underdeveloped on
one or both sides,
affecting the lower eyelid ,
the mandible and the
external ear.
• The prominence of the
cheek is absent, and the
ear may be displaced

25. PIERRE ROBIN SYNDROME
• It is characterized of a triad
of clinical signs.
• Micrognathia, glossoptosis
and obstruction of the upper
airways frequently associated
with palatal cleft.
• The hypothesis of Pierre
Robin anomaly is that usually
early mandibular hypoplasia
with obstruction of palatal
closure by a posteriorly

27. PRENATAL AND
POSTNATAL GROWTH OF
CRANIUM

28. •The number of bones in
adult skull is 22.
•The calvaria or brain
case is composed of 8
bones.
•The facial skeleton is
composed of 14 bones.

29. • Skull can be divided into :

30. PRENATAL GROWTH OF CRANIAL VAULT
• The mesenchyme that gives rise to the vault of skull is arranged first as a
capsular membrane around the developing brain.
• Membrane is composed of two layers:
• The mesodermally derived ectomenix gives rise to major portions of the
frontal, parietal, sphenoid, petrous temporal, and occipital bones.
• The neural crest provides the mesenchyme forming the lacrimal, nasal,
squamous temporal, zygomatic, maxillary & mandibular bone.
ECTOMENIX
Duramater that
covers brain
Calvarial bones,
bones of cranial base
ENDOMENIX
Pia &
Arachnoid
membrane
around brain

31. FRONTAL BONE
• A pair of frontal bone, from single
primary ossification center– in the
region of each superciliary arch (8
week IUL).
• 3 pairs of secondary centers –
zygomatic process, nasal spine and
trochlear fossae - fusion is complete
6-7 months of IUL.
• At birth, frontal bones are separated
by frontal (metopic) suture.
• Fusion of frontal suture begins -
2nd year.

32. PARIETAL BONES
•2 parietal bones arise
from 2 primary
ossification centers for
each bone that appear
at the parietal eminence
(8 week IUL).
•Fuse – 4th month IUL.

33. SQUAMOUS PORTION OF OCCIPITAL BONE( above
supranucheal Line)
• Ossifies from two centers - Intramembranously
• 8th week IUL.
SQUAMOUS PORTION OF TEMPORAL BONE
• Ossifies from single center appearing at the root of zygoma
(8weekIUL).
• Tympanic ring- ossifies from 4 centers, appearing in the
lateral wall of tympanum (3rd month IUL).

34. • The earliest centers of ossification first appear during the 7th and 8th
weeks post conception, but ossification is not completed until well
after birth.
• At birth, the individual calvarial bones are separated by sutures of
variable width and by fontanelles.
• Anterolateral fontanelles close 3 months after birth.
• Posterolateral fontanelles - 2nd year.
• Posterior fontanelles - 2 months after birth.
• Anterior fontanelles - 2nd year.
• At birth neurocranium has achieved 25% of its ultimate growth.
• 6 months – 50%
• 2 years - 75%
• 10 years - 95%

36. PRENATAL GROWTH OF CRANIAL
BASE
• Development of cranial base
commences at 4th week of IUL with
mesenchymal condensation between
the foregut and the developing brain
[neural tube].
• The mesenchymal condensation of
outer layer of ectomenix chondrifies at
40th day of IUL.
• Cranial base ossifies by endochondral
ossification.
• The cranial base consists of occipital
bone at the posterior end,
undersurface of body and greater wing

37. CHONDRIFICATION(MESENCHYMAL CELLS INTO
CARTILAGE)
Parachondral :
• The chondrification centers
around the cranial end of
notochord.
• It arises along the margins of the
cranial end of the notochord and
is derived from the occipital
sclerotomes and the first cervical
sclerotome (paraxial
mesenchyme origin).
• This sclerotome‐derived cartilage

38. Hypophyseal :
• Cranial to termination of
notochord , hypophyseal
pouch develops which
give rise to anterior lobe
of pituitary gland.
• On either side of
hypophyseal stem two
hypophyseal or
postsphenoid cartilage
develop, which fuse
together to form
posterior part of body of
sphenoid.
• Cranial to pituitary gland
, two presphenoid or
trabecular cartilages
develop which fuse

39. Nasal capsule :
• chondrifies around 2nd month of
IUL. Form cartilage of nostrils and
nasal septal cartilage.
Otic capsules :
• chondrify and fuse with the
parachordal cartilage and later
ossifies to form the
mastoid and petrous portion of
temporal bone.
• The initially separate centers of
cartilage formation in the cranial
base fuse together into a single
irregular and greatly perforated

40. OSSIFICATION

41. INTRAMEMBRANEOUS OSSIFICATION

42. ENDOCHONDRAL OSSIFICATION

43. OCCIPITAL BONE
• 7 osssification centers – 2 intramembraneous & 5 endochondral
• SUPRANUCHAL SQUAMOUS PART -
Intramembraneous ossification.
 2 ossification centre (8 week IUL)
• INFRANUCHAL SQUAMOUS PART -
Endochondral ossification.
 2 centres(10 week IUL)
• BASILAR PART - give rise to anterior
portion of occipital condyles and
anterior boundary of foramen
magnum.
 Endochondral ossification .
 Single median ossification centre (11
week IUL).
• LATERAL BOUNDARY OF FORAMEN
MAGNUM & POSTERIOR PORTION OF

44. TEMPORAL BONE
•Squamous part – single
intramembranous centre
(8th week IUL).
•Tympanic ring -4
intramembranous
centers(12 week IUL).
•Petrosal part -14
endochondral centers(16th
week IUL).

45. ETHMOID BONE
•Endochondral ossification.
•3 centers
•perpendicular plate and
crista galli-1
endochondral centre
•lateral labyrinth in the
nasal cartilage – 2
endochondral centers

46. SPHENOID BONE
Intramembraneous ossification
centers-
• Medial pterygoid plate- 2
• Lateral pterygoid plate -2
Endochondral ossification
centers-
• Pre sphenoid -3
• Post sphenoid -4
• Orbitosphenoids / lesser wings
-2
• Alisphenoids / greater wings -2

47. INFERIOR NASAL CONCHAE
• Endochondral bone.
• Single ossification center(5th month IUL).

48. CRANIAL BASE AND CRANIAL BASE
ANGULATION

49. (highly obtuse) (4 week
embryo)
(7-8 week )
(10
weeks)
(10-20
weeks)

50. •Growth of cranial base is highly uneven.
•Anterior and posterior parts of cranial base grows
at different rates.
•Between 10 and 40th week post conception ,
anterior cranial base- increases length & width 7
folds.
•Posterior cranial base grows – 5 folds.

51. POST NATAL GROWTH OF CRANIAL
VAULT
• Formed by intramembranous
ossification.
• At birth, the cranial vault is
63% of their adult size.
• Growth of Calvarial bones is a
combination of :
1) Sutural growth
2) Remodelling
3) Centrifugal
displacement by the expanding

52. SUTURAL GROWTH
• Adaptive growth
occurs at the coronal,
sagittal, parietal,
temporal and occipital
sutures to
accommodate the
rapidly expanding
brain.
• As the brain expands
and bones of cranial
vault are displaced
outwards.

53. REMODELLING
• Growth also occurs by
periosteal and endosteal
remodeling.
• The endosteal surfaces of
the inner and outer cortical
tables are resorptive.
• This increases the thickness
of the bone and expands the
medullary space between the
inner and outer tables.
• Apposition(deposition) - of
new bone at the sutures

54. TIMING OF GROWTH IN WIDTH ,LENGTH AND
HEIGHT

55. ROLE OF FUNCTIONAL MATRIX
THEORY
• In the neurocranium volume
of neural mass is
considered as the
determining factor.
• The expansion of this
enclosed and protected
capsular matrix volume is
the primary event in the
expansion of the
neurocranial capsule.
• The response of the

56. POSTNATAL GROWTH OF CRANIAL
BASE
• Cranial base is formed by
endochondral ossification.
• The endocranial surface of cranial
base is divided into anterior, middle
and posterior cranial fossae by bony
elevations.
• Cranial base grows postnatally by
complex interactions between the
following 3 growth processes :
1)cortical remodelling
2) synchondrosis

57. CORTICAL REMODELLING

59. SYNCHONDROSIS
• A synchondrosis is a cartilaginous immovable type of joint where hyaline
cartilage divides and is subsequently converted into bone.
• In the cranial base, four types of synchondroses are seen:
1) Intersphenoidal synchondrosis closes at birth
2) Intraoccipital synchondrosis closes at the 5th year
3) Sphenoethmoidal synchondrosis fuses at 5-20 years
4) Sphenoccipital or basioccipital - starts to fuse by 13-15
years of age and by 20 years it is completely fused.

60. • Synchondrosis is
considered as a growth
centre, which can generate
tissue separating force by
itself.
• Bipolar direction of growth
• Length of cranial base at
birth – 63% of adult size.
• First year- 83% complete.
• 15 years – 98% complete

61. SUTURAL GROWTH
• As the brain enlarges during
growth , there occurs
secondary fill in ossification
at the sutures.
• If only a sutural growth
mechanism were operative,
the expansion of the
hemispheres would cause
marked displacement
movements of the bones in
the cranial floor.
• The process of remodelling
growth in the cranial base

62. DEVELOPMENTAL ANOMALIES OF
CRANIUM
CLINICAL IMPLICATIONS

63. Study : Cranial base growth for Dutch boys and girls (AJO
1994 November)
- Monique Henneberke and
Birte Prahl Andersen
• In this study growth and development of the cranial base in
children who were treated orthodontically were compared
with children who were not.
• The hypothesis tested was that there is no difference in
cranial base growth between children with and without
orthodontic treatment.
• This is a mixed longitudinal study of
*153 boys and 167 girls samples for S-N
*116 boys and 116 girls for N-Ba and S-Ba

64. Cephalometric
points used in
this study.

65. Results:
•The effect of orthodontic therapy on cranial base
growth was apparently so limited that no significant
differences could be demonstrated between children
with or without treatment.
•The cranial base displayed sexual dimorphism in
absolute size, timing and amount of growth.
•All C.B. dimensions examined in this study were
greater in boys than in girls.
•Girls did not show adolescent growth spurts, where as
all boys showed that for S-N and N-Ba.

66. CRANIOSYNOSTOSIS
• Premature ossification
of one or several sutures
of the skull.
• This condition may lead
to abnormal skull shape
or retarded skull
growth.

67. CROUZON'S SYNDROME
• Premature fusion of the posterior and superior sutures of the maxilla
along the walls of the orbit with cranial base involvement.
• Characterized by :
1) Maxillary deficiency that affects the
infraorbital area.
2) Exophthalmoses.
3) Parrot beaked nose.
4) Hypertelorism.
5) Brachycephaly.
6) Mid-face hypoplasia.

68. APERT SYNDROME
• Similar to Crouzon's syndrome and have syndactyly as an additional
clinical feature.
• Characterized by :
1) midfacial malformations
2) syndactyly of hands and feet
3) mental retardation
4) Maxillary hypoplasia
5) Steep forehead
6) Ocular proptosis
7) Cleft palate

69. BEFORE TREATMENT
DURING
TREATMENT
AFTER
TREATMENT

70. ANENCEPHALY
• “Open skull”.
• Major portion of vault of skull is missing.
• Neural tube defect.
• Short, narrow chondrocranium.

71. ACHONDROPLASIA
•In achondroplasia, growth is
diminished at the
synchondroses.
•The resultant features include
short arms, legs and
characteristic midface deficiency
(most accentuated at the bridge
of the nose).
•The anterior cranial base is of

72. • The C.B. does not lengthen normally
because of deficient growth at the
synchondroses; the maxilla is not
translated forward to the normal
extent, and a relative midface
deficiency occurs.
• Premature ossification or synostosis
of the suture between the
presphenoid and post sphenoid
parts and of the sphenooccipital
suture produces a characteristic
apearance.
• This is seen in profile, and consists
of an abnormal depression of the

73. MICROCEPHALY
A rare neurological condition in
which an infant’s head is much
smaller than the heads of other
children of the same age and sex.

74. •Hypertelorism : Anomalous development of the
presphenoidal elements excessive separation between
the orbits and abnormally broad nasal bridge.
•Craniopharyngeal tumours : Coalescence of the
ossification centers in the body of sphenoid obliterates
the orohypopharyngeal track. Persistence of the track as
a craniopharyngeal canal in the sphenoid body gives rise
to craniopharyngeal tumours.
•Premature fusion of sphenooccipital synchondrosis in
infancy results in a depressed nasal bridge and dished
face.

75. CLEIDOCRANIAL DYSOSTOSIS
•CCD is characterized by
abnormalities of the skull,
jaws and shoulder girdle as
well as by occasional stunting
of long bones.
•In the skull, frontanelles
remain open or atleast exhibit
delayed closing.
•Frontal, parietal and occipital
bones are prominent and the
paranasal sinuses are

76. • Study: (AJO May 1981) : Kreiborg,Jensen,
Bjork and Skieller conducted a qualitative
screening for abnormal morphological
traits in the cranial base.
• The sample comprised 17 patients with
CCD (8 males and 9 females) 16-46 yrs
of age.
•Results:
• The anterior and posterior cranial base
was significantly shorter and the C.B.
angle smaller in the syndrome groups
than in the control groups.
• Clivus was distorted in 82 % of patients.
• All patients showed bulbous dorsum
sellae and many had small pituitary
fossae.

77. REFERENCES
• CRANOFACIAL EVELOPMENT- GEOFFREY H. SPERBER
• ESSENTIALS OF FACIAL GROWTH- DONALD H. ENLOW , MARK G. HANS
• ORTHODONTICS : CURRENT PRINCIPLES AND TECHNIQUES- GRABER,
VANARSDALL, VIG
• TEXTBOOK OF CRANIOFACIAL GROWTH- SRIDHAR PREMKUMAR
• CONTEMPORARY ORTHODONTICS- W.R PROFFIT
• LANGMAN’S MEDICAL EMBRYOLOGY BY T W SADDLER 11TH EDITION
• HUMAN EMBRYOLOGY BY INDERBIR SINGH 9TH EDITION
• INDERBIR SINGH’S HUMAN EMBRYOLOGY EDITED BY V SUBHADRA DEVI
11TH EDITION