prenatal and postnatal growth and development

CONTENT
 Definition of growth
 Definition of development
 Introduction
 To basic concepts of fertilization
 Period of ovum
 Introduction to the prenatal development of head and neck
 Pharyngeal apparatus
 Pharyngeal arches
 Pharyngeal pouches
 Pharyngeal grooves/clefts
 Applied anatomy of the branchial apparatus
7/28/2018 2

GROWTH AND DEVELOPMENT OF HEAD
AND NECK WITH DERIVATIVES OF FACE
AND TONGUE AND CLINICAL
APPLICATIONS
Dr. Yash Shah
1st year MDS
7/28/2018 3

CONTENTS (CONT..)
 Introduction To Development Of Face
 Development Of Upper Lip And Upper Jaw
 Development Of Lower Lip, Lower Jaw, philtrum And
External Eares
 Clinical Considerations
 Development Of Nose
 Development Of Eye
 Development Of External Ear
 Development Of Palate
7/28/2018 4

CONTENTS (CONTD)
 Development of Tongue
7/28/2018 5

CONTENTS (CONTD)
 Postnatal Growth
 Introduction
 Definitions
 What Is Postnatal Growth???
 Methods Of Studying Growth
 Theories Of Growth
 Principle Of Growth
 Growth Spurt
 Ossification
 Factors Affecting Growth
7/28/2018 6

CONTENTS (CONTD)
 Postnatal Growth Of
 Cranial Vault
 Cranial Base
 Nasomaxillary Complex Or Maxilla
 Mandible
 Reference
7/28/2018 7

INTRODUCTION
Embryology:- Study of development of an individual before
birth.
• Every individual spends the first nine months (266 days or 38 weeks
to be exact) of its life within the womb (uterus) of its mother.
• During this period it develops from a small one-celled structure to
an organism having billions of cells.
• Numerous tissues and organs are formed and come to function in
perfect harmony.
• Inderbir Singh; G.P. Pal- human embryology- seventh edition.
7/28/2018 8

• The most spectacular of these changes occur in the first two
months; the unborn baby acquires its main organs and just
begins to be recognizable as human.
• During these two months we call the developing individual an
embryo. From the third month until birth we call it a fetus.
7/28/2018 9
Inderbir Singh; G.P. Pal- human embryology- seventh
edition.

WHAT IS GROWTH?
• Increase in size, change in proportion & progressive
complexity (KROGMAN)
• Change in any morphologic parameter which is measurable
(MOSS)
• “An increase in size or number.” - Profitt. (1986)
• Growth signifies an increase, expansion or extension of any
given tissue.” - Pinkham.(1994)
7/28/2018 10
William r proffit[3rd edition]

WHAT IS DEVELOPMENT?
• Development is defined as-
• “Development is a progress towards maturity”
– Todd(1931)
• “Development connotes a maturational process involving
progressive differentiation at the cellular and tissue levels”
– Enlow
7/28/2018 11
William r proffit[3rd edition]

 Progress towards maturity (TODD)
Prenatal period can be devided into three periods:
1. Period of ovum
2. Period of embryo
3. Period of fetus
7/28/2018 12
Nikhil marwah[3rd edition

FERTILIZATION
• Fusion of sperm and ovum results in the formation of zygote
• Takes place in the ampula of uterine tube.
• Viability of gametes
• -Oocyte 12-24 h -Sperm 12-48 h7/28/2018 13

FORMATION OF BLASTOCYTE
Fertilized egg undergoes rapid
division
Morula
Fluid seeps into morula
Blastocyst
7/28/2018 15

Implantation
Embedding of blastocyst into
uterine lining begins at day 7
Lacunae and primary villi
formed by trophoblast
All of these form
placental tissues
Trophoblast forms syncytial
trophoblasterodes into endometrium
Cellular trophoblast carries nutrients to inner
cell mass
7/28/2018 17
Blastocyst - with blastocoele cavity
Trophoblast - outer layer of cells
Inner cell mass - will form embryo

FORMATION OF GERM LAYER
The three layers that
constitute this embryonic
disc are:
1. Endoderm {endo = inside)
2. Ectoderm (ecto = outside)
3. Mesoderm (meso = in the
middle)
 Some cells of the inner cell
mass differentiate into
flattened cells, that come to
line its free surface, These
constitute the endoderm,
which is thus the first germ
layer to be formed.
The remaining cells of the
inner cell mass become
columnar . These cells form
the second germ layer, the
ectoderm.7/28/2018 18
Inderbir Singh; G.P. Pal- human embryology-
seventh edition

• Cells of trophoblast give
origin to a mass of cell
called as Extra embryonic
mesoderm(primary
mesoderm).
• Space formed b/w Extra
embryonic mesoderm &
trophoblast by the fusion of
small cavities k/a Extra
embryonic coelom.
• Extra embryonic mesoderm
splits into 2 layers
• Somatopleuric mesoderm –
Forms Chorion
• Splanchnopleuric
mesoderm – Forms Amnion
7/28/2018 19
seventh edition

PROCHORDAL PLATE
• At one circular area near
the margin of the disc, the
cubical cells of the
endoderm become
columnar. This area is called
the prochordal plate.
• The appearace of the
prochordal plate
determines the central axis
of the embryo (i.e. enables
us to divide it into right and
left halves), and also
enables us to distinguish its
future head and tail ends.
7/28/2018 20
Inderbir Singh; G.P. Pal- human
embryology- seventh edition

PRIMITIVE STREAK
• The ectodermal cells lying
along the central axis, near
the tail-end of the disc,
begin to proliferate, and
form an elevation that
bulges into the amniotic
cavity. This elevation is
called the primitive streak.
7/28/2018 21
seventh edition

GASTRULATION
• Formation of Intra
embryonic mesoderm from
primitive streak.
• The cells that proliferate in
the region of the primitive
streak pass sideways,
pushing themselves
between the ectoderm and
endoderm. These cells form
the intra-embryonic
mesoderm (or secondary
mesoderm) which is the
third germ layer.
7/28/2018 22

7/28/2018 23
Age (in Days) Developmental Events
2 Embryo is at two-cell stage
3 Morula is formed
4 Blastocyst is formed
8 Bilaminar disc is formed
14 Prochordal plate and primitive
streak is seen
16 Intra-embryonic mesoderm is
formed/disc is now three layered.

Formation of notochord
• The notochord is a midline
structure, that develops in
the region lying between the
cranial end of the primitive
streak and the caudal end of
the prochordal plate.
• Cranial end of primitive
streak thickens & forms the
primitive node.
7/28/2018
Inderbir Singh; G.P. Pal- human embryology- seventh edition

7/28/2018 25
• Depression appears in the
center
– Blastopore
• Cells of primitive node
multiply & pass cranially in
midline up to the chordal
margin of prochordal plate
– Notochordal process
• Cavity of blastopore
extends in Notochordal
process to form a rod k/a
notochord
seventh edition

FORMATION OF NEURAL TUBE (3WK)
• Ectoderm overlying the
notochord thickens to form
Neural plate.
• Neural plate expands
toward primitive streak its -
Edges elevates to form
neural fold.
- Mid region depresses to
form neural groove.
• Neural folds approaches
each other in midline &
fuses to form neural tube.
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1. The neural tube gives rise to the brain and the spinal cord.
2. The neural tube is formed from the ectoderm overlying the
notochord and, therefore, extends from the prochordal plate
to the primitive knot
3. The neural tube is soon divisible into:
(a) a cranial enlarged part that forms the brain, and
(b) a caudal tubular part that forms the spinal cord.
4. In early embryos, the developing brain forms a large
conspicuous mass, on the dorsal aspect.
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seventh edition

SUBDIVISION OF INTRAEMBRYONIC
MESODERM
• Paraxial Mesoderm- Cells on either side of notochord
thickens.
• Lateral plate Mesoderm – Laterally mesoderm remains thin.
• Intermediate Mesoderm – longitudinal strip between the 2
layers.
• The paraxial mesoderm now becomes segmented into cubical
masses called somitomeres which give rise to somites . The
first somites are seen on either side of the midline, a little
behind the prochordal plate. More somites are formed
caudally, on cither side of the developing neural tube.
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seventh edition

FORMATION OF INTRA EMBRYONIC
COELOMIC CAVITY
• Small cavities appears in the lateral plate mesoderm,
coalesces to form one large horse shoe shaped cavity known
as Intra embryonic coelom.
• With the formation of the intraembryonic coelom, the lateral
plate mesoderm splits into:
• 1. Somatopleuric or parietal, intra-embryonic mesoderm that
is in contact with ectoderm.
• 2. Splanchnopleuric, or visceral, intraembryonic mesoderm
that is in contact with endoderm.
• The intra-embryonic coelom gives rise to pericardial, pleural,
and peritoneal cavities
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7/28/2018 31
• The heart is formed in the splanchnopleuric mesoderm forming
the floor of this part of the coelom This is, therefore, called
thecardiogenic area.

Establishment of gut
• The head & tail end of the disc remain
close together thus with increase in
length it bulges upward into the
amniotic cavity.
• Part of the yolk sac
encloses with in the
embryo thus a tube lined
by endoderm is formed known as
primitive gut. from which most of the
gastrointestinal tract is derived.
• Cranial part – Fore gut
• Caudal part – Hind gut
• Intervening – mid gut.
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seventh edition

Connecting Stalk
• Part of attachment of extra embryonic
mesoderm o trophoblast where extra
embryonic coelom does not extend
• Serve as connecting link between embryo &
placenta
• Arteries & veins between embryo & placenta
pass through it.
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• As the embryo grows, the area of attachment
of the connecting stalk to it becomes relatively
smaller. Gradually this attachment is seen only
near the caudal end of the embryonic disc
(Figs5.8D,E).
• With the formation of the tail fold,
the attachment of the connecting stalk moves (with
the tail end of the embryonic disc) to the ventral
aspect of the embryo. It is now attached in the
region of the umbilical opening (Fig. 5.8E).
• By now, blood vessels have developed in the
embryo, and also in the placenta. These sets of
blood vessels are in communication by means of
arteries and veins passing through the connecting
stalk.
• At first, there are two arteries and two veins
in the connecting stalk, but later the right vein
disappears (the left vein is 'left*').
7/28/2018 34

 Fig. F that, at this stage, the amnion has a circular attachment to the margins of
the umbilical opening and forms a wide tube in which the following lie:
1. Vitello-intestinal duct and remnants of the yolk sac.
2. Mesoderm (extra-embryonic) of the connecting stalk. This mesoderm gets
converted into a gelatinous substance called Wharton's jelly. It protects blood
vessels in the umbilical cord.
3. Blood vessels that pass from the embryo to placenta.
4. A small part of the extra-embryonic coelom. This tube of amnion, and the
structures within it, constitute the umbilical cord . This cord progressively
increases in length to allow free movement of the embryo within the amniotic
cavity. At the time of birth of the child (i.e. at full term), the umbilical cord is about
half a metre long, and about 2 cm in diameter.
7/28/2018 35
seventh edition

Neural Crest cells
• A group of cells separate from the neuroectoderm on
the lateral aspect of the neural plate.
• Undergo epithelial-mesenchymal interactions..
• Embryonic Connective tissue derived from mesoderm-
mesenchyme
• Form all tissues of tooth except enamel.
7/28/2018 36

Formation of Stomodeum
• 2 bulging appears on ventral aspect of embryo-
1- The cranial part of neural tube enlarges
(Which later forms brain).
2- Developing pericardial cavity enlarges rapidly and form
a bulging on the ventral side of embryo
(just below developing brain – This later forms thorax).
• Both of these have depression called the stomodeum.
(Forms future Mouth)
• Floor of stomodeum is formed by procordal plate known as
buccopharyngeal Membrane.
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• A primordial pharyngeal (branchial) apparatus develops in human
embryos
• By the end of the embryonic period, these structures have either become
rearranged and adapted to new functions or disappeared.
• The pharyngeal apparatus consists of
 Pharyngeal arches
 Pharyngeal pouches
 Pharyngeal grooves
 Pharyngeal membranes
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PHARYNGEAL ARCHES
• The pharyngeal arches begin to develop early in the 4th week
as neural crest cells migrate into the future head and neck
regions
• The 1st pair of pharyngeal arches, which is the primordium of
the jaws, appears as surface elevations lateral to the
developing pharynx
• Soon other arches appear as obliquely disposed, rounded
ridges on each side of the future head and neck region
7/28/2018 41

• The 5th and 6th are rudimentary and are not visible on the surface of the
embryo
• The pharyngeal arches are separated from each other by the pharyngeal
grooves
• The arches and grooves are numbered in a cranio-caudal sequence
7/28/2018 42

PHARYNGEAL ARCH COMPONENTS
 A typical pharyngeal arch contains
 A pharyngeal arch artery that arises from the truncus arteriosus of the
primordial heart
 A cartilaginous rod that forms the skeleton of the arch
 A muscular component that differentiates into muscles of head and neck
 Sensory and motor nerves that supply the mucosa and muscles derived
from the arch
7/28/2018 44

I
(Mandib
ular)
Meckel’s cartilage Incus,
malleus
• Anterior mandible
• Zygomatic bone
• Palatine bone
• Part of temporal bone
• Ligament of the malleus
• Sphenomandibular ligament
formation of maxilla
Mandibular-
third
division of the
V
cranial nerve
Medial and lateral pterygoid
• Masseter
•Temporalis
• Mylohyoid
• Ant.belly of digastric
• Tensor tympani ,Tensor
palati
II Hyoid Stapes
• Styloid process
• Smaller cornu of hyoid bone
• Superior part of body hyoid
bone
Facial Muscles of face
• Occipitofrontalis
• Platysma, stylohyoid
• Post belly of digastric
• Stapedius
• Auricular muscles
III Greater cornu of hyoid bone
•Lower part of the body of
hyoid bone
Glosso-
pharyngeal
Stylopharyngeus
IV Cartilages of larynx are derived
from both
IV and VI
Superior
Laryngeal
All The muscles of pharynx
except stylopharyngeus
• All the muscles of palate
except tensor veli palate
• Cricothyroid muscle
VI Recurrent
7/28/2018 46

• The pouches develop in a craniocaudal sequence between the
arches
• There are 4 well defined pairs of pharyngeal pouches; 5th pair
is either rudimentary or absent
7/28/2018 47
PHARYNGEAL POUCHES

PHARYNGEAL POUCHES
7/28/2018 48

PHARYNGEAL GROOVES/CLEFTS
• The head and neck region of the human embryo exhibits 4 pharyngeal
grooves (clefts) on each side during the 4th and 5th week.
• The grooves separate the pharyngeal arches externally.
• Only one pair of grooves contribute to post natal structures
• The first groove persists as the external acoustic meatus
• The other grooves lie in a slit like depression-the cervical sinus- which are
normally obliterated as the neck develops
7/28/2018 49

APPLIED ANATOMY OF THE
BRANCHIAL APPARATUS
• 1.CONGENITAL AURICULAR SINUSES AND CLEFTS
• Usually located in a triangular area of skin anterior to the
auricle of the external ear
• These are at times remnants of the 1st pharyngeal groove
• They are a minor anomaly and of no serious medical
consequence.
7/28/2018 50

2. BRANCHIAL FISTULA
• It is an abnormal canal that opens internally into the tonsillar sinus
and externally in the side of the neck.
• It results from the persistence of the 2nd pharyngeal groove and
pouch.
7/28/2018 51

3. BRANCHIAL CYSTS
• Remnants of parts of cervical sinus and or the second pharyngeal groove.
• Can develop anywhere along the anterior border of the
sternocleidomastoid muscle.
• They do not usually become apparent till early adulthood, when they
produce a slowly enlarging painless swelling in the neck.
• The cysts enlarge because of the accumulation of fluid and cellular debris
derived from desquamation of their epithelial lining
7/28/2018 52

4. FIRST ARCH SYNDROME
• Abnormal development of the components of the first
pharyngeal arch results in various congenital anomalies
of the eyes , ears, mandible and palate that together
constitute the 1st arch syndrome
• Comprises of 2 main manifestations
1. TREACHER COLLINS SYNDROME(
MANDIBULOFACIAL DYSOSTOSIS)
2. PIERRE ROBIN SYNDROME
7/28/2018 53

DEVELOPMENT OF FACE
• The basic morphology of the face is created 24th and 38th day of gestation
- development & fusion of the prominences:-
– Frontonasal prominence
– Maxillary swellings
– Mandibular swellings
• At 24 days, maxillary process & mandibular process are formed.
7/28/2018 54

 Early development is dominated by proliferation and migration of
ectomesenchyme involved in the formation of primitive nasal
cavities.
 At about 28 days, localized thickening develop within ectoderm of
the frontal prominence - olfactory or nasal placodes.
 Rapid proliferation of mesenchyme - Horse shoe shaped ridge -
nasal pits.
7/28/2018 55

Development of Face (4 wk)
• Mesoderm covering the developing forebrain
proliferates & form a downward projection k/a
frontonasal process.
FRONTONASALPROCESS
MAXILLARY PROCESS
MANDIBULAR PROCESS
STOMODEUM
Maxillary process – Lateral to stomadeum
Mandibular process – Caudal to stomadeum
7/28/2018 56

• On both side of frontonasal prominence local
thickening of
surface ectoderm
originates k/a
nasal placodes
NASAL
PLACODE
MAXILLARY
PROMINENCE
7/28/2018 57

FRONTONASALPROCESS
EYE
MAXILLARY PROCESS
STOMODEUM
2nd ARCH
3rd ARCH
MEDIAL NASAL PROCESS
LATERAL NASAL PROCESS
1st ARCH
MANDIBULAR PROCESS
• Nasal placodes invaginate to form nasal pits.
• They creates a ridge tissue that surrounds each pit & forms nasal
prominences
• Prominence on
Outer edge – Lateral nasal prominence.
Inner edge – Medial nasal prominence7/28/2018 58

Development of nose
Frontonasal
prominence
forms Bridge
Medial nasal
process
forms Crest & Tip
Lateral nasal process
forms Alae
7/28/2018 59

Upper lip formation
• Formation of nose leads to rounding of
stomatodeum to form upper part of upper lip
• Lateral part of upper lip is formed by maxillary
process nd median part by fronto nasal process.
7/28/2018 61

Lower lip formation
• Formed by mandibular prominences that
merge across the midline
7/28/2018 62

Development of Cheek
• Stomodeum is bounded above by
maxillary process and below by
mandibular process.
• These processes fuses
together to form the cheek
7/28/2018 63

• EYES: The eyes develop from
the lens placode which are
ectodermal thickenings
present lateral and cranial to
the nasal placode.
• EYELID: Eyelids are derived
from folds of ectoderm that
are formed above and below
the eyes, and by mesoderm
enclosed within the folds.
7/28/2018 64

PINNA: The pinna (auricle) is formed by the fusion of the
mesodermal thickenings on the mandibular and hyoid arches.
NASOLACRIMAL DUCT: Nasolacrimal duct is formed by
fusion between the lateral nasal & maxillary processes,
separated by a deep groove. The epithelium in the floor of the
groove between them forms a solid core that separates from the
surface and eventually canalizes to form nasolacrimal duct.
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7/28/2018 66
PROMINENCE STRUCTURES FORMED
1 Frontonasal Forehead, Bridge of nose, Medial
& Lateral nasal prominences
2 Maxillary (P) Cheeks, lateral portion of upper
lip & UPPER JAW
3 Medial nasal (P) Philtrum of upper lip, Crest &tip
of nose
4 Lateral nasal (P) Alae of nose
5 Mandibular(P) Lower lip & LOWER JAW

Developmental anomalies of the face
• Harelip
• Oblique facial cleft
• Macrostomia
• Lateral facial cleft
• Retrognathia
• Agnathia
• Mandibulofacial dysostosis
• Hypertelorism
• Congenital pits and fissure on lips
• Proboscis
7/28/2018 67

7/28/2018 68
OBLIQUE FACIAL CLEFT HARELIP
PROBOSCIS

DEVELOPMENT OF MOUTH
• The mouth is derived partly from the stomatodeum
(ectodermal) and partly from the foregut (endodermal).
• After the disappearance of the buccopharyngeal
membrane the stomatodeum communicates with the
foregut.
• Epithelium lining the lips, cheek, palate; teeth and gums
are ectodermal in origin.
7/28/2018 69

• Epithelium of the tongue is endodermal.
• In the region of the floor of the mouth; the mandibular
process forms the lower lip, lower parts of cheek, lower jaw
and tongue.
7/28/2018 70

Development of palate
• From each maxillary process, a plate-like shelf grows medially;
called palatal process.
• The palate is formed from the 3 components:
• The two palatal processes
• The primitive palate formed from the frontonasal process
7/28/2018 72
Robert e moyers; handbook of orthodontics[4th edition]; chapter
no 2; page no 6-16

PRIMARY PALATE
• By the fusion of the maxillary
and nasal processes in the roof
of the stomodeum.
• the primitive palate (or
primary palate) is formed, and
the olfactory pits extend
backward above it.
• It consists of the maxillary
process and medial nasal
process.
• The lip and primary palate
close during the 4th to 7th
weeks of gestation.
7/28/2018 73
no 2; page no 6-16

SECONDARY PALATE
• The development of the
secondary palate commences in
the sixth week of human
embryological development.
• It is characterised by the
formation of two palatal shelves
on the maxillary prominences.
• As the palatal shelves grow
medially their, their union is
prevented by the presence of
tongue.
• Initially the developing palatal
shelves grow vertically toward
the floor of mouth.
7/28/2018 74
no 2; page no 6-16

• During 7th week of intrauterine life, a transformation in the position of the
palatine shelf occurs.
• They change from a vertical to a horizontal position.
 Various reasons are given to explain how this transformation occurs.
They are:
• Alteration in biochemical and physical consistency of the connective tissue of
the palatal shelves
• Alteration in vasculature and blood supply to the palatal shelves
• Apperance of an interensic shelf force
• Rapid differential mitotic activity
• Muscular movements
7/28/2018 75
no 2; page no 6-16

• The 2 palatal shelves, by 8 ½ weeks of intra uterine life are in close
approximation to each other
• Initially the 2 palatal shelves are covered by an epithelial lining.
• As they join the epithelial cells degenerate
• The connective tissue of the palatal shelves intermingle with each other
resulting in their fusion
• The entire palate does not contact and fuse at the same time. Initially the
contact occurs in the central region of the secondary palate posterior to
the premaxilla
• From this point, closure occurs both anteriorly and posteriorly
7/28/2018 76

OSSIFICATION OF PALATE
• Ossification of the palate occurs from the 8th week of intrauterine
life. This is an intramembranous type of ossification
• The palate ossifies from a single centre derived from the maxilla.
• The most posterior part of the palate does not ossify. This forms the
soft palate
• The mid palatal suture ossifies by 12-14 yrs
7/28/2018 77
no 2; page no 6-16

Developmental anomalies of lips and
palate
• Congenital lip
• Commissural pits and fistulas
• Van der woude syndrome
• Cleft lip and cleft palate
• Chelitis glandularis
• Chelitis granulomatosa
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7/28/2018 79
• Complete non-fusion,
giving rise to a Y-shaped
cleft, accompanied by
bilateral harelip.
• The left maxillary
process has fused
with the premaxilla,
but not with the right
maxillary process.
• The cleft is
accompanied by
unilateral harelip.
Midline cleft
extending into
the hard palate
Cleft lip and cleft Palate

7/28/2018 80
Cleft of soft palate
Bifid uvula.
 Syndrome associated with cleft lip and cleft palate:
o Autosomal dominant:
• Vander woude syndrome
• Trecher collins syndrome
• Cleidocrainal syndrome
• Stickler’s syndrome
o Autosomal recessive
• Robert’s syndrome
• Appet syndrome
• Christian syndrome
• Meckel syndrome

DEVELOPMENT OF TONGUE
• Develops at about 4 weeks.
• Pharyngeal arches meet at the midline beneath the primitive mouth.
• Local proliferation gives rise to a number of swellings in the floor of the
mouth.
• The anterior two-third of the tongue is formed
• by fusion of:
• (a) the tuberculum impar, and
• (b) the two lingual swellings.
7/28/2018 82
7thedition;chapter no 4-9; page no 34-104

• The posterior one-third of
the tongue is derived from
the cranial part of the
hypobranchial eminence
(copula)
• The posterior-most part of
the tongue is derived from
the fourth arch.
• Posterior part of the fourth
arch marks the
development of the
epiglottis.
7/28/2018 83
Inderbir Singh; G.P. Pal- human embryology- 7thedition;chapter
no 4-9; page no 34-104

• The anterior two-third of the tongue is supplied by the lingual
branch of the mandibular nerve, which is the post-trematic
nerve of the first arch, and by the chorda tympani which is the
pre-trematic nerve of this arch.
• The posterior one-third of the tongue is supplied by the
glossopharyngeal nerve, which is the nerve of the third arch.
• The most posterior part of the tongue is supplied by the
superior laryngeal nerve, which is the nerve of the fourth
arch.
7/28/2018 84
Inderbir Singh; G.P. Pal- human embryology- 7thedition;chapter
no 4-9; page no 34-104

Muscles of tongue
• Muscles develop from occipital myotomes.
7/28/2018 86
Extrinsic muscles Intrinsic muscles
Genioglossus Superior longitudinal
Hyoglossus Inferior longitudinal
Styloglossus Transverse
Palatoglossus vertical
Gray’s anatomty 2nd edition page no 1470

Exterinsic muscles
7/28/2018 87

Intrinsic muscles
7/28/2018 89
Gray’s anatomty 2nd edition page no 1470

7/28/2018 91
There is also a secondary blood supply to the tongue from the tonsillar branch of
the facial artery and the ascending pharyngeal artery
B.d chaursiya volume 3;3rd edition;page no253-255

Nerve supply
• Motor supply for all intrinsic and
extrinsic muscles of the tongue is
supplied by efferent motor nerve
fibers from the hypoglossal
nerve (CN XII), with the exception
of the palatoglossus, which is
innervated by the vagus
nerve (CN X)
• Anterior two thirds of tongue
(anterior to the vallate papillae):
• Taste: chorda tympani branch of
the facial nerve (CN VII)
via special visceral afferent fibers
• Sensation: lingual branch of the
mandibular (V3) division of
the trigeminal nerve
7/28/2018 92
• Posterior one third of tongue:
• Taste and sensation: glossopharyngeal
nerve (CN IX)
• Base of tongue
• Taste and sensation: internal branch of
the superior laryngeal nerve

Lymphatic drainage
• Tip of tongue-bilaterally
submental nodes.
• The right and left halves
of remaining part of
anterior two-third of
tongue drain to
submandibular lymph
node.
• Posterior one third
drains bilaterally to
jugulo-omohyoid nodes.
7/28/2018 93

Anomalies of tongue
• Macroglossia, microglossia, aglossia
• Bifid tongue
• Ankyloglossia
• Persistence of tuberculum impar
• Thyroid tissue within the muscles
• Remnants of thyroglossal duct
• Fissured tongue
7/28/2018 94

7/28/2018 95
Bifid tongue Ankyloglossia
Fissured tongue Median Rhomboid Glossitis

DEVELOPMENT OF MANDIBLE
• 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 extends from the otic capsule to the midline of the
fused mandibular processes.
7/28/2018 96
William r proffit;contemporary orthodontics[4th edition];chapter
2 ;page no 27-47

• A major portion of the Meckel’s carlitage disappears during
growth and the remaining part develop into the
 following structures:-
• The mental ossicles
• Incus and malleus
• Spine of sphenoid bone
• Anteriorligament of malleus
• Spheno mandibular ligament
7/28/2018 97
2 ;page no 27-47

• The mandible is derived from the
ossification of an osteogenic
memberane formed from
ectomesenchymal condensation
at around 36- 38 days IU.
• The resulting intramemberanous
bone lies lateral to meckel’s
cartilage of the first arch.
• A single ossification centre for
each half of the mandible arises
in the 6th week IU, in the region
of the bifurcation of the inferior
alveolar nerve and artery into the
mental and incisive branches.
7/28/2018 98
2 ;page no 27-47

7/28/2018 99
• As a result mandibular length
increases, the external auditory
meatus appears to move
posteriorly.
• Bone begins to develop lateral to
Meckel’s cartilage during the 7th
week and continues until the
posterior aspect is covered with
bone.
• This is the marked acceleration of
the mandibular growth between
the 8th and 12th week IU.
2 ;page no 27-47

• Ossification stops at the point,
which will later become the
mandibular lingula and, the
remaining part of meckel’s
cartilage continues on its own to
form sphenomandibular ligament
and the spine process of
sphenoid ossification.
• Meckel’s cartilage does, however,
persist until as long as the 24th
week IU, before it disappears.
7/28/2018 100
2 ;page no 27-47

ENDOCHONDRAL BONE FORMATION
• Endochondral bone formation is seen in 3
areas of mandible-
1) The condylar process
2) The coronoid process
3) The mental process
7/28/2018 101S.i.bhalajhi[4th edition]

• At fifth week of intrauterine life , an area of mesenchymal
condensation is seen above the ventral part of developing
mandible.
• At about tenth week it develops in cone shaped cartilage.
• It migrate inferior & fuses with mandibular ramus at about 4
month.
7/28/2018 102

THE CORONOID PROCESS
• Secondary accessory
cartilage appear in region of
coronoid process at about
10- 14 week of intrauterine
life.
• This cartilage become
incorporated into expanding
intramembranous bone of
ramus & dissappear before
birth.

THE MENTAL REGION
• In mental region , on either
side of symphysis , one or two
small cartilage appear and
ossify in seventh week of
intrauterine life to become
mental ossicles.
• These ossicles become
incorporated into
intramembranous bone when
symphysis ossify completely.

DEVELOPMENT OF RAMUS
• Rapid spread of ossification
posteriorly into the
mesenchyme of the 1st arch.
• Point of divergence is marked
by the lingula in the adult
mandible.
• Spread of mandibular
ossification away from meckels
cartilage at the lingula.
7/28/2018 106

DEVELOPMENT OF MAXILLA
• 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
7/28/2018 107
2 ;page no 27-47

7/28/2018 108
• Bony trough forms for the infraorbital nerve and from this trough
downward extension forms lateral alveolar plate.
• Ossification spreads to the palatine process and forms hard palate.
• Median alveolar plate forms from the junction of the palatal
process & the main body of the forming maxilla.
• A secondary cartilage; zygomatic or malar cartilage appears in the
developing zygomatic process.
2 ;page no 27-47

DEVELOPMENT OF MAXILLARY SINUS
• 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.
7/28/2018 109

Developmental anomalies of jaws
• Agnathia
• Micrognathia
• Macrognathia
• Facial hemihyperatrophy
• Facial hemiatrophy
7/28/2018 110

7/28/2018 111
Agnathia Micrognathia
Macrognathia Facial hemiatrophy

7/28/2018 112
POSTNATAL GROWTH AND
DEVELOPMENT

METHOD OF STUDYING GROWTH
7/28/2018 113
MEASUREMENT APPROCH EXPERIMENTAL APPROCHES
•They comprise of
measurement techniques that
are carried out on living
individual.
•These methods do not harm
the animal.
•These are destructive
technique where the animal
that is studied is sacrifice,
experimental approaches are
not carried out on humans.
•Examples:
1. Craniometry
2. Cephalometry
3. Anthropometry
4. Bimetric test
•Examples
1. Vital staining
2. Radio isotops
3. Implants
4. Genetic Influences on
Growth

Craniometrics
• The first of the measurement approaches for studying growth,
with which the science of physical anthropology began, is
craniometry, based on measurements of skulls found among
human skeletal remains.
• Craniometrics has the advantage that rather precise
measurements can be made on dry skulls.
7/28/2018 114

7/28/2018 115
• Craniometrical studies are based on
measurements between landmarks on
dried skulls
Robert e moyers; handbook of orthodontics[4th edition]; chapter no 2;
page no 6-16

Anthropometry
• It is also possible to measure skeletal dimensions on living
individuals this technique called anthropometry
7/28/2018 116
page no 6-16

Cephalometric Radiology
• Cephalometric radiology, is of considerable importance
not only in the study of growth but also in clinical
evaluation of orthodontic patients.
• This approach can combine the advantages of
craniometry and anthropometry.
• It allows a direct measurement of bony skeletal
dimensions, since the bone can be seen through the
soft tissue covering in a radiograph.
• The disadvantage of a standard cephalometric
radiograph is that it produces a two-dimensional (2-D)
representation of a three dimensional (3-D) structure.
7/28/2018 118
page no 6-16

A cephalometric radiograph merits this name because of the use
of a head positioning device to provide precise orientation of the
head.
7/28/2018 119

Bimetric test
• They are tests in which physical characteristics such
as weight , height , skeletal maturation and
ossification are measured and compared with
standards based upon the examination of large
groups of healthy subjects.
7/28/2018 120

Experimental Approaches
 Vital Staining [Belchier in 1936]
• Much has been learned about skeletal growth using the
technique called vital staining, in which dyes that stain
mineralizing tissues(or occasionally, soft tissues) are injected
into an animal.
• It is possible to study the manner in which bone is laid down,
the site of growth ,the direction , duration , and amount of
growth at different sites in the bone.
7/28/2018 121
page no 6-16

The Dyes used for this purpose are
• Alizarin Red 5
• Acid alizarin blue
• Trypon blue
• Tetracycline
• Lead acetate
7/28/2018 122

Implant Radiography [Bjork in 1969]
• Another experimental method applicable to studies of
humans is implant radiography.
• The use of implants to study bone growth.
• In this technique, inert metal pins are placed in bones
anywhere in the skeleton, including the face and jaws. These
metal pins are well tolerated by the skeleton, become
permanently incorporated into the bone without causing any
problems, and are easily visualized on a cephalogram.
7/28/2018 123

Genetic Influences on Growth
• Rapid advances in molecular genetics are providing new
information about growth and its control. For example,
homeobox Msx genes, which are known to be critically
important in the establishment of body plan, pattern
formation, and morphogenesis, have been found to be
expressed.
7/28/2018 125
page no 6-16

RADIOISOTOPES
• Radioisotopes of certain element or compounds ,
when injected into tissue get incorporated in the
developing bone and act as in vivo markers .
• These radioisotopes can later be detected by tracking
down the radioactivity .
• The radio-isotopes used include
– Technetium-33
– Calcium-45
– Potassium-32
7/28/2018 126
page no 6-16

• The Overall changes in body proportions during normal
growth and development occur due to an axis of increased
extending from head towards feet.
• During the fetal period : at about second month of
intrauterine life , head measure about 50% of the total body
length.
• At birth : the proportion changes due to faster growth rate of
limbs and trunk compared to the head and face. head
measure about 25-30%of the total body.
• Adult hood : progressive reduction of relative size of the head
to about 12% and legs represent half the total body length.
7/28/2018 129
S.i.bhalajhi[4th edition

• Lower limb are rudimentary around 2nd month of iintrauterine
life. In adult hood it represent almost 50% of body weight
• At birth crainaium is proportionally larger than
face.postnatally face grows more than cranium.
7/28/2018 130

Scammon’s Growth Curve
7/28/2018 131

The body tissue can be broadly classified into four
types each of these tissue grows at different times
and rates.
• Lymphoid tissue : Proliferate rapidly in late childhood and
reaches almost 200%of adult size. this is an adaptation to
protect children from infection, as they are more prone to
it. By about 18year of age ,lymphoid tissue undergoes
involution to reach adult size.
• Neural tissue : grows vary rapidly and almost reaches adult
size by 6-7year of age. Very little growth of neural occur
after 6-7year
7/28/2018 132

 General tissue : consists of the muscles, bone and other organs.
These tissue exhibit an “S” shaped curve with rapid growth upto 2-
3 year of age. followed by a slow phase of growth between 3-
10years.after the tenth year, rapid phase of growth occurs
terminating by the 18-20 year.
 Genital tissue : consists of the reproductive organs. They show
negligible growth until puberty. However they grow rapidly at
puberty reaching adult size after which growth ceases.
7/28/2018 133

Growth Spurts
• Growth does not take place uniformly at all times. There
seems to be periods when sudden acceleration of growth
occurs. This sudden increase in growth Is termed as Growth
Spurt
• The Physiological alteration in hormonal secretion is believed
to be the cause for such accentuated growth.
• The timings of the growth spurts differ in boys and girls
7/28/2018 134

 The following are the timing of growth spurts.
• Just before birth
• One year after birth
• Mixed dentition growth spurt
boys : 8-11years
girls : 7-9 years
• Pre-pubertal growth spurt
boys : 14-16 years
girls : 11-13 years
7/28/2018 135

7/28/2018 136
Growth
assessment
Clinical
Body weight
and height
Dental
eruption
Chronological
age
Sexual
cheracteristic
Radiographical
Skeletal
maturity
Hand wrist
radiograoh
Cervical vertebre
maturity
Dental maturity
Using opg
Robert e moyers; handbook of orthodontics[4th edition]; chapter no 2; page no 6-16

7/28/2018 137
Percentile curves for weight and length by age for boys for birth to 36 month.
• Same percentile curves for weight and length for girls and boys birth to 20 years.
• This growth chart created by the national center for health statistics.
Nelson textbook of pediatrics [18th edition]volume
1;chapter no 9;page no 50

DIFFERENT METHODS OF
USING HAND WRIST
RADIOGRAPH
1. Fisherman skeletal maturation indicator
2. Bjork, Grave and Brown
3.Hagg and Taranger method
4.Atlas of Greulich and Pyle
7/28/2018 138

HAND
WRIST RADIOGRAPH
7/28/2018 139

Fisherman skeletal maturation
indicator
7/28/2018 140

7/28/2018 141
Stage 1..width of
Epiphysis
equal that
of Diaphysis i.e. E=D
1. Middle finger
proximal
phalanx…PP3
2. Middle finger middle
phalanx…MP3
3. Little finger middle
phalanx..MP5
Stage II. Adductor
sesamoid of thumb.
4. Centre of ossification
medial to
the junction
of the epiphysis and
diaphysis of
the proximal
phalanx of the thumb
S.i.bhalajhi[4th edition]

7/28/2018 142
Stage III. Capping
5. Middle finger distal phalanx
DP3
6. Middle finger middle
phalanx
MP3
7. Little finger middle phalanx
MP5
Stage IV. FUSION
8. Middle finger distal phalanx
DP3
9. Middle finger proximal phalanx
PP3
10. Middle finger middle phalanx
MP3
11. Radius

Cervical Vertebra Maturation
Indicator
• INDICATION
-Assessment of completion of active growth
- To identify clinically the adequate time for
intervention in subjects who need surgery
- For prediction of growth spurt
- Predicting the correct direction of growth

7/28/2018 146
1. Initiation.
- Very significant amount of
adolescent growth
expected
- C2, C3, and C4 inferior
vertebral body borders are
flat.
- Superior vertebral borders are
tapered posterior
to anterior i.e. trapezoids
2. Acceleration.
- Significant amount of adolescent
growth
expected.
- Concavities developing in lower
borders of C2
and C3.
- Lower border of C4 vertebral
body is flat.
- C3 and C4 are more trapezoid in
shape

3. Transition .
- Moderate amount of
adolescent growth expected
- Distinct concavities seen in
lower borders ofC2 and C3.
- C4 developing concavity in
lower border of vertebral
body.
- C3 and C4 are rectangular in
shape.
4. Deceleration.
- Small amount of
adolescent growth
expected
- Distinct concavities in
lower borders of C2,
C3,and C4.
- C3 and C4 are nearly
square in shape.

5. Maturation.
- Insignificant amount of
adolescent growth expected.
- Accentuated concavities on
inferior borders of C2, C3, and
C4.
- C3 and C4 are square in
shape.
6. Completion.
- Adolescent growth is
completed.
- Deep concavities are present
on inferior borders of C2,C3,
and C4.
- C3 and C4 heights are greater
than widths.

THEORIES OF GROWTH AND
DEVELOPMET
7/28/2018 149
1 Sicher’s theory of suture growth
2 Scott’s cartilaginaous theory
3 Functional matrix theory
4 Servosystem theory of growth
5 Van limborg’s view of craniofacial growth
6 Genetic theory
7 Enlow and bang’s “v” principal
8 Servo-system theory

Sicher’s theory of sutural [Weinmann
and Sicher,1947]
• According to this theory , suture were responsible for majority
of the craniofacial growth which was also predicted by using
vital dyes.
• Sicher felt that connective tissue in suture of vault and
nasomaxillary complex produced forces that separate the
bone and cause expansion.
7/28/2018 150

 Examples to support this theory
• If suture are pulled apart bone fills in and if suture are
compressed, then there is impeded growth.
 Against this theory
• Sutures when transplanted from face to abdominal pouch do
not growth
• Presence of forces triggers bone resoreption and deposition.
• Growth can be seen in case of clef palate patients even in
absence of sutures.
7/28/2018 151

Cartilaginous theory of growth [James
scott,1953]
• James Scott , an Irish anatomist proposed that cartilaginous
nasal septum has future and occupies a strategic position that
might causes the midface region to displace rather than the
suture.
• Because the cartilage is more pressure tolerant it has more
capacity to push the nasomaxillary complex downward and
forward , thus giving rise to the nasal septum theory.
7/28/2018 152

• Examples to support this theory
• although there is no cartilage in maxilla , there is a cartilage in
nasal septum and this nasomaxillary complex grows as a unit.
• nasal septum and epiphyseal cartilage continue to grow when
implanted in cultures thus showing their innate growth
potential
• removal of nasal septum lead to midfacial deformities.
 Examples of against this theory
• Mandibular condylar cartilage does not grow in culture
showing that there are some cartilages that are not growth
centers but are just site of growth
7/28/2018 153

Genetic theory [Brodie,1941]
• This theory had proposed that genes control all the
function of growth and development .
 Examples to support this theory
• This implies that such tissue do not entirly govern their
own differention; their growth is controlled by genetic
influence.
 Examples against this theory
• Relationship between genotype and phenotype of man
and apes.
• Large biological differences observad between 2 species
with similar karyotypes
7/28/2018 154

Functional matrix theory [moss,1962]
• This theory claimed that the control for growth was not in
cartilage or bone but in adjacent soft tissue thus emphasizing
that neither the nasal septum nor the mandibular condyle are
determinates of growth .
• In this theory he told the growth of face occurs as a response
to functional needs and is mediated by the soft tissue in
which jaws are embedded.
7/28/2018 155

Functional matrix
This consists of teeth , organs, gland , muscles , nerves and
vessels as well as nonskeletal cartilage
• It divided into two parts
• Periosteal matrix : [non skeletal units ]
• Capsular matrix
1.Neurocranial capsule
2.Orofacial capsule
7/28/2018 156

Skeletal unit
• This skeletal unit may be comprised of bone , cartilage or
tendon . All skeletal tissues are related to a specific functional
matrix.
1. Microskeletal unit
number of small skeletal units.
[mandible]
2. Macroskeletal unit
[maxilla]
7/28/2018 157

Support
this theory
• Growth of cranial vault is
directly a response of
growth of brain.
• Enlarge or small eye will
correspondingly changes
the size of orbit
Against this
theory
• In hydrocephalic patient ,
the size of brain is small but
the cranial vault is bigger
7/28/2018 158

Van limborg’s theory [1970]
• This theory suggested five factors that control growth.
• Intrinsic genetic factors : genetic control of the skeletal unite themselves.
• Local epigenetic factors : bone growth is determined by genetic control
originating from adjacent factors like brains,eyes etc.
• General epigenetic factors : growth from distant structures like growth
hormones ,sex hormones.
• Local environmental factors : like habit and muscle force.
• General environmental factors : like oxygen, nutrition,etc.
7/28/2018 159

Enlow’s expanding “V”principle
7/28/2018 160

The Basic Concept of Bone Growth is
the “V” Principal
• Bone deposition occurs on the inner surface ‘v’ whereas
resorption occurs on the outer surface.
• Some of the bones which grow according to this pattern are
end of long bones , base of mandible ,mandibular body and
palate
7/28/2018 161

Cybernetics / servo-system theory
[petrovic , stutzman, 1974]
• Using the language of cybermetics , petrovic reasons that it is
the interaction of series of casual changes of feedback
mechanisms which determine the growth of craniofacial
regions.
• According to this theory , control of primary cartilage takes a
cybernetics from of a command whereas control of secondary
cartilage is comprise of indirect and direct effects of cell’s
multiplication.
7/28/2018 162

Osteogenesis
• The process of bone formation is called osteogenesis.
• Two types.
1. Endochondral bone formation
2. Intra-membranous bone formation
7/28/2018 163

Endochondral bone formation
• In this type of osteogenesis the bone formation is preceded
by formation of a cartilaginous model that subsequently
replaced by bone.
• Small parts of cartilage may remain at the junction of various
bones.these are called “synchondroses”
• This are important growth site of cranial base.
7/28/2018 164

The importance of chondrosis found in cranial
base
• Spheno-occipital synchondrosis
• Sphenoethmoidal synchondrosis
• Intersphenoid synchondrosis
• Interoccipital synchondrosis
7/28/2018 165

Intra-membranous bone formation
• In this type of ossification , the formation of bone is
not preceded by formation of a cartilaginous model.
Instead bone is laid down directly in fibrous
membrane
7/28/2018 166

Growth site
• Some growth fields having special
roles in the growth of particular
bones are called growth sites.
• These include. the mandibular
condyle, symphysis menti,
alveolar ridge, posterior border of
ramus. the maxillary tuberosity,
the synchondroses of the
basicranium, the sutures.
 Growth center
• Some growth sites have been
called" growth centers," a term
which implies that a special area
somehow controls the overall
growth of the bone.
• The term "growth center" also
implies that the "force," "energy,"
or "motor" for a bone resides
primarily or solely within its
growth center.
• it is still argued whether or not
the mandibular condyle and the
synchondroses in the cranial base
are growth centers
7/28/2018 167

Postnatal growth of head and neck
i. Cranial vault
ii. Cranial base
iii. Maxilla (nasomaxillary complex)
iv. Mandible
7/28/2018 168

Cranial Vault
• The cranial vault is made up of a number of flat bones that are
formed directly by intramembranous bone formation, without
cartilaginous precursors.
• Remodelling and growth occur primarily at the periosteum-
lined contact areas between adjacent skull bones, the cranial
sutures, but periosteal activity also changes both the inner
and outer surfaces of these plate like bones.
7/28/2018 169

7/28/2018 171

• At birth, the flat bones of the skull are rather widely separated
by loose connective tissues . These open spaces, the
fontanelles, allow a considerable amount of deformation of
the skull at birth.
• This is important in allowing the relatively large head to pass
through the birth canal.
• After birth, apposition of bone along the edges of the
fontanelles eliminates these open spaces fairly quickly, but
the bones remain separated by a thin, periosteum-lined
suture for many years,eventually fusing in adult life.
7/28/2018 172

Hydrocephalus
• Hydrocephalus (from Greek hydro-, meaning "water",
and ceph, meaning "head") is a medical condition in which
there is an abnormal accumulation of cerebrospinal fluid (CSF)
in the brain. This causes increased intracranial pressure inside
the skull and may cause progressive enlargement of the head
if it occurs in childhood, potentially causing convulsion, and
mental disability.
7/28/2018 173

An infant with severe hydrocephalus
7/28/2018 174

Craniosynostosis
• Craniosynostosis is a condition in which one or more
of the fibrous sutures in an infant skull prematurely
fuses by turning into bone .
• thereby changing the growth pattern of the
skull. Because the skull cannot expand perpendicular
to the fused suture.
7/28/2018 175

Cranial Base
• In contrast to the cranial vault, the bones of the base of the
skull (the cranial base) are formed initially in cartilage and
these cartilage models are later transformed into bone by
endochondral ossification.
• As indicated previously, centers of ossification appear early in
embryonic life in the chondrocranium, indicating the eventual
location of the basioccipital, sphenoid, and ethmoid bones
that form the cranial base.
7/28/2018 177

• As ossification proceeds, bands of cartilage called
synchondroses remain between the centers of ossification
• These important growth sites are the synchondrosis between
the sphenoid and occipital bones, or spheno-occipital
synchondrosis; the intersphenoid synchondrosis between two
parts of the sphenoid bone; and the spheno-ethmoidal
synchondrosis between the sphenoid and ethmoid bones.
7/28/2018 178

Maxilla (Nasomaxillary Complex)
• The maxilla develops postnatally entirely by intramembranous
ossification.
• Since there is no cartilage replacement, growth occurs in 3
ways:
1. Displacement :
 primary displacement
 secondry displacement
2. surface remodeling.
3. growth at sututes
7/28/2018 179

As the maxilla is carried downward and forward, its
anterior surface tends to resorb.
7/28/2018 180

Displacement
• Apposition of bone at the sutures that
connect the maxilla to the cranium and cranial
base.
• Primary displacement
• Secondary displacement
7/28/2018 181

Primary displacement
• If a bone gets displaced as a result of its own growth, it is
called primary displacement.
• Example :
growth of maxilla at the tuberosity region results in
pushing of the maxilla against the cranial base which results in
displacement of the maxilla in a forward and downward
direction.
7/28/2018 182

Secondary displacement
• If the bone gets displaced as a result of growth and
enlargement of an adjacent bone , it is called secondary
displacement.
• Example
the growth of the cranial base causes the forward and
downward displacement of the maxilla.
7/28/2018 183

Surface Remodelling
7/28/2018 184
Remodelling refers to a process where bone deposition
and resorption occur so as to bring about change in size
, shape and relationship of the bone.

• Resorption on lateral surface and
deposition on external surface of
orbit rim-for lateral movement of
eye ball.
• Surface deposition on superior,
lateral and anterior surface of
floor of orbit.
• Deposition along posterior aspect
of maxillary tuberosity-for 3rd
molar
• Resorption along lateral wall of
nose-incerese size of nasal cavity.
7/28/2018 185
• Resorption on anterior and
deposition on posterior
surface of zygomatic bone.
• Bone deposition on
alveolar margins-to
accommodate teeth.

Sutural growth
• The maxilla is connected to the cranium and cranial base by a
number of suture.
a. fronto-nasal suture
b. fronto-maxillary surute
c. zygomatico-temporal suture
d. zygomatico-mixillary suture
e. pterygo-palatine suture
7/28/2018 186

Mandible
• Both endochondral and
periosteal activity are important
Ingrowth of the mandIible.
• Mandible is the most diverse
bone in human craniofacial
sutucture as it is made-up of
many small individual bones
which on their own are mini-
skeletal units.
• The postnatal growth of
mandible is best understood if
the development of all parts of
mandible is undertaken
individually.
7/28/2018 188

Ramus
• Deposition on posterior
aspect and resorption on
anterior aspect to move the
ramus posteriorly to
accommodate for molars and
to accommodate increasing
muscle mass of masticatory
muscles.
7/28/2018 189

Body of mandible
• The incerease in width
of the mandible occurs
primarily due to
resorption on inside
and deposite on out
side.
• Increase in length
occurs due to drift of
ramus posteriorly.
• Incerease in height
occurs due to eruption
of teeth.
7/28/2018 190

Angle of mandible
• Lingually , there is resorption on posterioinferior aspect and
deposition on anteriosuperior aspect. Buccally there is
deposition on posteriosuperior aspect .this results flaring of
angle of mandible.
7/28/2018 191

Lingual tuberosity
• The lingual tuberosity moves
posteriorly by deposition on its
posterior facing surface
• Lingual tuberosity protrudes
noticeably in a lingual direction
and that it lies well toward the
midline of the ramus.
• The prominence of the tuberosity
is increased by the presence of a
large resorption field just below it
• The resorption field produces a
sizeable depression, the lingual
fossa.
7/28/2018 192

Coronoid process
• Deposition occurs on lingual surface and further growth is
based on enlarging ‘v’ principle takes place posteriorly.
7/28/2018 193

Condyle
• Growth may either occur by bone deposition along condylar
cartilage which then intearect with cranial base thus
displacing mandible downward and forward or it may occur as
growth of soft tissue surrounded in the rigion later followed
by bone formation.
7/28/2018 194

Alveolar process
• Develops as a
response to
presence of teeth
by increasing in
thickness and
height by
deposition at
margins.
7/28/2018 195

chin
• Enlow & harris feel that chin is
“associated with a generalised
cortical recession in the flattened
regions positioned between the
canine teeth.
• The process involves a
mechanism of endosteal cortical
growth.”
• As the age advances the growth
of chin becomes significant
• Usually males have prominent
chin as compared to females
• Prominence of mental
protuberance is accentuated by
bone resorption that occurs in
the alveolar region above it,
creating a concavity
7/28/2018 196

Factors affecting growth
 Systemic factors
1. Genetics
2. Hormonal imbalance
3. Nutrition
4. Systemic illness or
chronic illness
5. Localized alteration
6. Systemic illness in
mother
7. drugs
 Local factors
1. Vascular abnormality.
2. Lymphatic disturbance
3. Neurologic disease
4. Local infection
5. Ear infection
6. Ankylosis
7. Trauma or fracture
8. Birth injury
7/28/2018 197

Anomalies of mandible
 Syndrome associated
with mandibular
abnormality
I. Down’s syndromr
II. Marfan’s syndrome
III. Tumers syndrome
IV. Kleinfelter’s syndrome
V. Pierre-robin syndrome
VI. Treacher collin
syndrome
 Congenital
• Agnathia
• Micrognathia
• Facial hemihypertrophy
• Facial hemiatrophy
7/28/2018 198

7/28/2018 199
Nelson textbook of pediatrics [18th edition]volume
1;chapter no 9;page no 36

7/28/2018 200Nelson textbook of pediatrics [18th edition]volume 1;chapter no 9;page no 36

References
• Inderbir Singh; G.P. Pal- human embryology- 7thedition;chapter no 4-9;
page no 34-104
• Kumar GS, Orban’s Oral Histology and Embrology, 13th Ed, Elsevier Mosby.
• William r proffit;contemporary orthodontics[4th edition];chapter 2 ;page
no 27-47
• Robert e moyers; handbook of orthodontics[4th edition]; chapter no 2;
page no 6-16
7/28/2018 201

• Nikhil marwah;textbook of pediatric dentistry[3rd edition]; chapter no
13;page no 89-94
• Ray E. stewart; pediatric dentistry scientific foundation and clinical
practice;chapter no 1;page no 11-34
• Nelson textbook of pediatrics [18th edition]volume 1;chapter no 9;page no
50
• S.i.bhalajhi[4th edition]
• Gray’s anatomty 2nd edition page no 1470
• B.d chaursiya volume 3;3rd edition;page no253-255
7/28/2018 202

prenatal and postnatal growth and development

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