Growth & development of cranium /fixed orthodontic courses

GROWTH AND
DEVELOPMEN
T OF CRANIUM
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INDIAN DENTAL ACADEMY
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 Introduction
 Bone growth
 Synchondroses
 Sutures
 Prenatal growth of cranium
 Cranium at birth
 Postnatal growth of cranium
 Theories of growth
 Anomalies of development
 Clinical significance
 Conclusion

Robert E Moyer's has defined growth as normal
changes occurring in amount of the living
substances. According to him, growth is the
quantitative aspect of biologic development.

Development: It refers to all the naturally

occurring unidirectional changes in the life of an
individual from its existence as a single cell to its
elaborations as a multifunctional unit terminating to
death.


We can put this in the formula of
Development
growth + differentiation +
translocation.

Differentiation: it is the change for
generalized cells or tissues to more
specialized kinds during development and
translocation in change in position.


 According to Todd – Growth is an increase in

size and development is progress towards
maturity
 According to J.S. Huxley – Growth is self-

multiplication of living substance.
 According to Krogmen – Growth is increase

in size, change in proportion and progressive
complexity.

 At the time of birth there are 45 bony elements

separated by cartilage.
 At the end of one year, it is decreased to 22 after the
completion of ossification.
 14 of these bones are in the face and the remaining
8 form the cranium.
 The reduction in the number is due to growth and
union at various sutures and endochondral junctions.
 At the time of birth, the cranium is 8-9 times larger
than the facial portion.


Within one year it becomes twice the
size of face
Development of skull, comprising both
the cranium and mandible, is a blend of
morphogenesis and the growth of 3
main skull entities arising from
→ neural crest and
→paraxial mesoderm tissues

Skull entities is composed of
 Neurocranium
Calvaria (desmocranium)
Cranial base (Chondrocranium)
 Face
Masticatory apparatus.


BONE GROWTH


Before we study the growth of the
various parts of craniofacial complex,
it is important to know how the bone
grows. Bone is always connective
tissue

The terms cartilaginous or
endochondral and membranous
or intramembranous identify the
type of connective tissue.

Bone is composed of two entities
- Osteocytes
Intercellular substance
Osteocytes are two types
Osteoblasts – bone forming cells
Osteoclasts – bone resorbing
cells.


Endochondral bone formation
At the site where the bone is to be formed,
the mesenchymal cells become closely
packed
to
form
a
mesenchymal
condensation.
Some
mesenchymal
cells
become
chondroblasts and lay down hyaline
cartilage.
Mesenchymal cells on the
surface of the cartilage form a membrane
called the perichondrium. This membrane
is vascular and contains osteogenic cells.

The cells of the cartilage are at first small
and irregularly arranged.. however in the
area where bone formation is to begin, the
cells enlarge considerably.
The intercellular substance between the
enlarged cartilage cells becomes calcified
under the influence of an enzyme called
alkaline phosphatase, which secreted by the
cartilage cells. The nutrition to the cells is
thus cut off and they die, leaving behind
empty spaces called primary areolae.

Some blood vessels of the perichondrium
now invade the calcified cartilaginous
matrix.
They are accompanied by osteogenic
cells. This mass of vessels and cells is
called the periosteal bud. It eats away
much of the calcified matrix forming the
walls of the primary areolae, and thus
creates large cavities called secondary
areolae. Thus formation of cartilaginous
model takes place.

The walls of the secondary areolae are
formed by thin layers of calcified matrix
that have not been dissolved.
The
osteogenic cells become osteoblasts and
arrange themselves along the surfaces of
these bars, or plates, of calcified
cartilaginous matrix.


INTRAMEMBRANOUS OSSIFICATION
These osteoblasts now lay down a layer of
ossein fibrils embedded in a gelatinous
intercellular matrix. This material is called
osteoid. It is calcified and a lamellus of
bone is formed.
The osteoblasts now lay down another layer
of osteoid over the first lamellus. This is
also calcified. Thus two lamellae of bone are
formed. Some osteoblasts that get caught
between the lamellae form osteocytes. As
more lamellae are laid down, bony trabeculae
are formed.

Synchondroses


The cartilage junctions between
two bones are called
synchondroses.
They are important growth sites
cranial base.

Synchondroses found in cranial
base are
1. Spheno - occipital
2. spheno – ethmoidal
3. inter- sphenoidal
4. intra- occipital


Spheno- occipital – it is the cartilaginous
junction between the sphenoid and the
occipital bones. It is active up to the age of
12-15 years. The sphenoid and the occipital
segments then become fused in the midline
area by 20 years of age.
spheno- ethmoid - this is a cartilaginous
band between the sphenoid and ethmoid
bones. It ossifies at 8 to 25 years of age


Inter sphenoid - it is a
cartilaginous band between the
2 parts of the sphenoid bone. It
is believed to ossify at birth.
Intra occipital: - this ossifies by 35 years of age.

Suture

They are fibrous joints
comprised of sheets of dense
connective tissue that
separate the bones of calvaria
The sutures help the calvaria
to change shape during birth

Types of sutures
1.

2.
3.

4.

5.

coronal sutures - it is present between
posterior border of frontal bone and anterior border
of parietal bone
Saggital sutures - it is present between upper
borders of parietal bones in the median plane
lambdoid sutures – it is present between posterior
borders of parietal bones and upper border of
occipital bone
parieto mastoid stutures - it is present between
free upper border of mastoid part of temporal bone
and posterior part of parietal bone.
occipito mastoid sutures – it is present between
posterior border of mastoid part of temporal bone
and squamous part of occipital bone.

PRENATAL
GROWTH OF
CRANIUM

Cranial base growth is due to proliferation of
cartilage and its replacement by bone, primarily
at synchodroses.
Cranial vault or desmocranium growth
is accomplished by proliferation of connective
tissue between the sutures and its replacement
by bone. The periosteum also grows, but it is a
limiting membrane determining the size and
shape changes. Despite the rapid ossification
of the cranial vault in the terminal stages of fetal
life, the bones of desmocranium are separated
from each other by the fontanels when the child
is born.

CRANIUM
AT
BIRTH

At birth, bones of face and jaws are underdeveloped
The ratio between cranium and face is 8:1 at birth,
later the ratio
decreases to 2:1 in the adult.
Bones of cranial vault do not complete their
growth during fetal life.
The point where more than 2 bones meet the sutures
are wide open are called Fontanelle (soft spots).
Fontanelle are regions of dense connective tissue
where sutures joins.

Types of Fontanelle
Anterior Fontanelle
It is the largest
It is seen at the junction of sagittal, coronal and frontal
suture.
It is diamond shaped.
It ossifies between 1 ½ to 2 years of age posterior

Posterior Fontanelle
It is triangular in shape and located at the function of
sagittal
and lambdoid suture.
It ossifies 2 to 3 months after birth

Antero lateral Fontanelle (Sphenoidal)
2 pairs
It ossifies 2 to 3 month after birth
Postero lateral Fontanelle (Mastoid)
2 pairs
Ossifies at 1 to 2 year of birth


P

Postnatal
growth
Of
cranium

It is divided into
Brain case
Cranial base.


Growth of cranial base
Cranial base grows by cartilage growth in the
sphenoethmoidal, inter sphenoethmoidal, spheno
occipital, and intra occipital synchondroses.
It follows a neural growth curve, but partially the
general growth curve.
Activity at the inter sphenoidal synchondroses
disappears at birth.
Intra occipital synchondrosis closes in the third to
fifth year of life.
Spheno occipital synchondrosis is a major
contributor.
Endochondral ossification does not stop here
until twentieth year of life.

Growth of brain case
The cranium grows because the brain grows.
By the end of fifth year of life, over 90% of the growth of
the brain capsule or brain vault has been achieved.
This increased in size is achieved by proliferation and
ossification of sutural connective tissue and by
appositional growth of individual bones that make up the
cranial vault.
Apposition can be seen on both the internal and external
tables of the cranial bones as they become thicker.
.

The cranial vault increases in width by “fill in”
ossification of proliferating connective tissues in the
coronal lambdoidal, interparetal, parieto shpenoidal
and parictotemporal sutures.
The mid sagittal sutures between the
parietal bones does not close until the middle of the
3rd decade of life.
Increase in length of brain may be
primarily due to the growth of cranial base with
active response at the coronal suture.
The brain case grows in height with
active response at parietal sutures along with the
occipital, temporal, and sphenoidal contiguous
osseous structures

CHONDROCRANIAL OSSIFICATION
Approximately 110 ossification centers
appear in the embryonic human skull.
Many of these centers fuse to produce 45
bones in the neonatal skull. In the young
adult, 22 skull bones are recognized.


Cartilage Dominance theory – By James
Scott,
According to the theory the genetic control is
expressed at cartilage
Scott said that the cartilaginous sites through out
the skull are primary growth centers.
The nasal septal cartilage is the pacemaker for
growth of the entire nasomaxillary complex.
The mandible is considered as a long bone bent into
a horseshoe shape with the epiphysis removed, so
that the cartilage contributes help and epiphyseal
plate at the ends, which are represented by
condyles.

FUNCTIONAL MATRIX THEORY – BY
MELVIN MOSS, 1960, 1962, 1997
Moss’s idea of growth control is that the growth
control lies in adjacent soft tissues and cartilage
bones are just sites.
The growth of the face occurs as a response to
functional needs and is mediated by the soft
tissues conceptually the soft tissues growth,
bone, and cartilage reacts to it.
A number of relatively independent functions are
carried out in the craniofacial regions or the
human body like, respiration, olfaction, vision,
hearing, balance, chewing digestion, swallowing
speech and neural integration.

Functional cranial
components
Skeletal Unit – Micro skeletal, Macro
skeletal Unit

Functional Matrices
Capsular Matrices
Periosteal Matrices

–

Skeletal Unit

:

The skeletal tissues associated with
a single function are called “the
skeletal unit”. It is comprises of
bone, cartilage and tendinous
tissues.


functional matrix
The consists of muscles, glands, nerves, vessels,
fat, teeth and the functional spaces

Periosteal matrix
Their action is directly and actively upon the
related skeletal units, alternations in their
functional demands produce a secondary
compensatory translation of size or shape of their
skeletal units. Such processes are brought about
by the inter related process of bone deposition
and resorption eg. Muscles, blood vessels,
nerves glands etc.

Capsular Matrix
They act directly and passively on their related skeletal units
producing secondary compensatory translation in space.
These alterations in spatial position of skeletal units are
brought by expansion of the orofacial capsule within which the facial
bones arise, grow and are maintained.
The facial skeletal units are passively and secondarily moved
in space as their enveloping capsule is expanded.
Deposition and resorption do not bring about this kind of
translative growth.
The neurocranial capsule and the oro-facial capsule are
examples of capsular matrices.
Each of the capsules is an envelope, which contains a series
of functional cranial components (skeletal units), which as a whole
are sandwiched in between two covering layers.

In Neuro cranial capsule, the cover is skin
and duramater and in oro-facial capsule, the
skin and mucosa forms the covering.
The neurocranial capsule
surrounds and protects the neurocranial
capsular functional matrix, which is the
brain, leptomeninges and CSF.

The neuro cranial capsule is made up
of skin,connective tissue aponeurotic
layer; loose connective layer,
periosteum, base of skull and layers of
duramater

The orofacial capsule surrounds and
protects the oro-naso-pharyngeal spaces,
which constitute the matrix. The growth
of the facial skull is influenced by the
volume and potency of the spaces.

Van Limborgh’s theory, 1970
Limborgh explains the process of growth and
development in the view that combines all the
major theories.
He supports the Moss’s functional Matrix
Theory
Acknowledges certain concepts of Sicher’s
Theory
Never did he rule out the genetic theory.


Unloaded Nerve theory – by Melvin
Moss
The skeletal units and growth field fulfills the
demands for protection of the mandibular
nerve by formation of bone around .


Sero system theory – By petrovic
and stutzmann 1980
the theory states that the influence of somatotropic
complex is STH- Somatomedin hormones, sexual
hormones and thyroniel hormones on the primary
cartilage (epiphyseal cartilages of long bones,
cartilages of the nasal septum and sphenoid etc)
has the “Cybernetic” form of common.


Enlow’s counterpart principle
The growth of any given facial or cranial part relates
specifically to another structural and geometric
counterparts of the face and cranium.
This counterpart principle explains the balanced
growth between different regions of the cranium
even thought they have different growth rates .

Different cranial base parts and their
counterparts.
Anterior base and nasomaxillary complex.
Middle cranial fossa and horizontal pharyngeal
space dimensions.
Middle cranial fossa and breadth of the ramus.

Anomalies
of
development

The calvaria is particularly susceptible to a number of
congenital defects ranging from chromosomal to hormonal in
their etiology.
The time of closure of the sutures is altered in many
of these afflictions, leading to variable distortion of skull shape
In conditions such as cretinism, progeria, trisomy21
and cleidocranial dysostosis there is delayed midline
ossification of frontal and saggital sutures of the calvaria, so
that anterior fontenelle may remain open into adult life.
The resulting brachycephalic skull results in a bossed
forehead of highly curved frontal and parietal bones and
hypertalorism, partly obscuring the smaller brain case.
Another abnormality is premature fusion of sutures
(craniosynostosis)
Encephaloceles are defects in closure of the foramen
caecum at the ethmoid frontal suture allowing hernation of the
cranial contents into the face

In anencephaly absence of the calvaria results in
craniosehisis, characterized by short narrow
chondrocranium.
Afflication of cartilage growth produce a
reduced cranial base, with increased angulation due to
loss of flattening effect of growth of spheno occipital
synchondroses.
This results in dished deformity of middle
1/3rd of facial skeleton accentuated by a bulging of
neurocranium.
Achondroplasia, cretinism and Down’s
syndrome all produce a similar characteristic facial
deformity by their inhibiting effect on chondrocranial
growth.
Certain forms of dental malocclusion may
be related to defects of the chondrocranium that minimize
the space available for the maxillary dentition.

VARIOUS SYNDROMES AND
DEFECTIVEDEVELOPMENTAL
CONDITIONS
SYNDROME 13 TRISOMY–
EXTRA CHROMOSOME 13 IS PRESENT.
CHARACTERIZED BY CLEFT LIP AND PALATE,
MICROPTHALMIA (SMALL EYES), MICROCEPHALY WITH
SEVERE BRAIN MALFORMATION, CONGENITAL HEART
DEFECTS, POLYDACTILY (EXTRA DIGITS) AND A HOST OF
OTHER ANOMALIES.


Trisomy 18 syndrome (Edwards
syndrome)
Most cases of this trisomy result into
spontaneous abortion
It occurs 1 in 6500 population
Early death is the characteristic feature
Retarded growth and development
Prominent large forehead (occiput )
Small chin
Heart defects are commonly seen

APERT SYNDROME:
IS A SINGLE GENE DISORDER,
CHARACTERIZED BY PREMATURE FUSION
OF CRANIAL SUTURES, BIZARRE
CRANIOFACIAL APPEARANCE, HIGHLY
ARCHED PALATE, SYNDACTYLY (FUSION
OF DIGITS) AND VARIOUS OTHER
ABNORMALITIES OCCASIONALLY
INCLUDING CONGENITAL HEART DEFECTS.
THE PATIENT HAS BIZARRE PHYSICAL
APPEARANCE AND MENTAL RETARDATION
UNLIKELY TO MARRY AND HAVE CHILDREN.

Craniosynstosis –
It is a condition resulting from premature fusion of
the cranial sutures like Apert syndrome.
In this, head shape depends on which sutures are
prematurely synostosed, the order in which they
synostose and timing at which they synostose.
This condition may be prenatal or perinatal in
onset or may occur later during infancy or
childhood.
The earlier the synostoses occur, the more
dramatic is the affect on subsequent cranial
growth and development.
The later synostosis occurs, the less is the effect
on the cranial growth and development.

The various shapes of the calvaria when
various sutures are prematurely fused are
Normocephaly – is the normal head shape
Dolicocephaly – if the saggital suture is
prematurely synostosed, the calvaria is restricted in
its lateral growth and compensates by permitting
more passive growth to occur at the coronal and
lambdoidal sutures.
Brachycephaly – if the cornonal suture is
prematurely synostosed, growth is arrested in an
antero posterior direction, compensatory growth
occurring laterally at the patient saggital suture.

Plagiocephaly – is an asymmetric skull
shape. This may be produced by
unilateral closure of the coronal suture
or unilateral closure of the lamboidal
suture.
Trigonocephaly – if the metopic suture
closes prematurely a triangular
calvaria results known as
Trigonocepyhaly.

Achondroplasia
Characterized by unusual crainio facial
configuration and disproportional short
stature.
Chromosomal disorder (autosomal dominant)
Enlarged calvaria, frontal bossing, large
frontal sinus, occipital prominence, normal
anterior cranial base length, shortened
posterior cranial base length, shortened
posterior cranial base length, short upper
facial height, short nasal bone, short upper
facial height, short maxilla, posterior tilt of
nasal floor.

Prognathic mandible that is anteriorly placed
but of normal size, normal gonial angle and
high coronoid process.
In achondroplasia bone preformed
in cartilage is affected
Membrane bones are not affected.
The condition is due to abnormal
endochondral bone formation on the
development of skull as a whole.
The mandible is normal in length because
growth a condylar cartilage is appositional.
In achondroplasia only interstitially
growing cartilage is affected.

Marfan’s syndrome
Hereditary disease.
Basically defect of connective tissue
related to defective organization of
collagen.
Shape of face is long and narrow.
High arched palate.
Also seen are excessive length of tubular
bones and arachnodactaly or spidery
fingers.


Down’s syndrome
Flat face .
Large anterior fontanelle, open suture,
small slanting eyes with epicanthal folds,
open mouth, frequent prognathism
Sexual underdevelopment, cardiac
abnormality and hypermobility of jaws.


Hyperthyroidism
Under functioning of thyroid gland due to failure of
pituitary gland or atrophy or destruction of the
thyroid gland.
Decreased ability of the thyroid gland to produce
sufficient hormone.
Here base of the skull is shortened leading to
retraction of the bridge of the nose with flaring.
The face is wide failing to develop in the
longitudinal direction .
The mandible is underdeveloped and the maxilla is
overdeveloped .
Mental retardation.

Cleidocranial dysplasia: It is a disease of unknown etiology, often hereditary.
Characterized by abnormalities of the skull, teeth,
jaws and shoulder girdle and stunting of long bones.
In the skull the fontanells remain open or at least
show delayed closure
The sagittal suture is characteristically sunken
giving the skull a flat appearance.
Shoulder meets in midline.


Clinical
Importance

Craniofacial skeletal growth is very important in
orthodontics since craniofacial morphology are the
source of serious malocclusions.
The configuration of the basicranium determines a
person’s head form type, which in turn sets up many
proportionate features characterizing facial type.
If the basicranium is long and narrow, this result in
dolicochphalic facial type, which will result anterioposteriorly and vertically, elongated facial profile and this
will result in mandibular retrusion.
If the basicranium is round, this will result in
brachycephalic facial type, this will result in anterioposteriorly and vertically shorter facial profile. This will
result in either mandibular protrusion or bimaxillary
protrusion.

The growth of the cranium also has direct
effect on the placement of maxilla and
mandible.
The mandible is attached to mid cranial fossa
through the condyles.
Thus ramus place the mandibular arch in occlusion
with the maxillary arch following a pattern set up by
the basicranium.
Similarly, the nasomaxillary complex is suspended
from the anterior cranial fossa. So the configuration
of the palate and maxillary arch is thus established
by the basicranium

CONCLUSION
A thorough background in craniofacial growth is necessary for
every orthodontist.

Even for those who never work with

children, it is difficult to comprehend conditions observed in
adults without understanding the development processes that
produced these problems.
Craniofacial skeletal growth is very important in orthodontics,
since variations in craniofacial morphology are the source of
most serious malocclusions and clinical damages.


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