The document discusses growth and development of the maxilla from prenatal to postnatal periods. It describes how the maxilla develops from maxillary processes in the embryo. During prenatal growth, the maxilla is displaced downward and forward as the cranial base grows. Postnatally, the maxilla grows through bone deposition, remodeling at sutures, and expansion of the maxillary sinus. The primary palate develops early from the median palatine process, while the secondary palate forms from the palatine shelves fusing in the midline.

2. The study of head form in man has always been of
considerable interest to anthropologist, anatomists, &
other students of human growth.
 In fact, the wide array of students involved in solving the
complex phenomenon of “GROWTH” have been aptly
described by Krogman as early as 1943 in these golden
words:-
“ Growth was conceived by an
anatomist ,born to a biologist ,delivered by a physician,
left on a chemist’s doorstep & adopted by a physiologist.
At an early age she eloped with a statistician, divorced
him for a psychologist & is now being wooed , alternately
& concurrently by an endocrinologist,a pediatrician , a
physical anthropologist, an educationalist , a biochemist ,
a physicist , a mathematician , an orthodontist , a
eugenicist & the children’s bureau”.

3. According to “TODD”
“Growth is an increase in
size.”
&
“Development is progress
towards maturity .”

4. Some definitions related to Growth
As is the nature of growth where in the concepts
keep changing with new research findings there
has been no single definitions associated with it:
Different researchers have defined growth in
various ways.
-The self multiplication of living substance – JX
Huxely.
- Increase in size, change in proportion & progressive
complexity.- Krogman
-Entire series of sequential anatomic & physiological
changes taking place from the beginning of
prenatal life to senility –Meredith.
-Quantitative aspect of biologic development per
unit of time-Mayers
-Change in any morphological parameter, which is
measurable-Moss.

5. Terminology Related To Growth:
GROWTH FIELDS :
The outside & inside surfaces of a bone are
blanketed by a mosaic-like, pattern of soft tissues , cartilage or
osteogenic membrane called as Growth Fields.
They when altered are capable of producing an alteration
in the growth of the particular bone.
GROWTH SITES :
Growth sites are growth fields that have a special
significance in the growth of a particular bone.
Eg. Mandibular condyle in the mandible,
Maxillary tuberosity in the maxilla.
The growth sites may possess some intrinsic potential to
growth.

6. REMODELING :
It is the differential growth activity involving
simultaneous deposition & resorption on all the inner &
outer surfaces of the bone.
Eg. Ramus moves posteriorly by a combination of
resorption & deposition.
GROWTH CENTERS:
Growth centers are special growth sites ,
which control the overall growth of the bone.
Eg. Epiphyseal plates of long bone.

7. Mechanism Of Bone Growth
• Bone is a specialized tissue of mesodermal origin.It
forms the structural framework of the body.
• Bone is calcified tissue that supports the body &
gives points of attachment to the musculature.
• Normal bone contains between 32-36% of organic
matter.
-Bone deposition & resorption
-Cortical drift
-Displacement

8. BONE DEPOSITION & RESORPTION:
Bone changes in shape & size by two basic mechanisms,bone
deposition & bone resorption.The bone deposition & resorption
together is called “ BONE REMODELING”.
The changes that bone deposition & resorption can produce
are:
 Change in size
 Change in shape
 Change in proportion
 Change in relationship of the bone with
adjacent structures.

9. Cortical Drift
 Most bones grow by interplay of bone
deposition & resorption .
A combination of bone deposition & resorption
resulting in a growth movement towards the
deposition surface is called “Cortical Drift”.
If bone deposition & resorption on either side
of a bone are equal
The thickness of the bone remains constant.
If in case more bone is deposited on one side
& less bone resorbed on the opposite side
The thickness of the bone increases.

10. Displacement:
•It is the movement of the whole bone as a unit.
•Displacement can be of two types.
Primary displacement:
If a bone gets displaced as a result of its own
growth, it is called “Primary displacement”.
e.g.. Growth of the maxilla at the tuberosity region results in pushing
of the maxilla against the cranial base which results in pushing of
the maxilla against the cranial base which results in the
displacement of the maxilla in a forward & downward direction.
Secondary displacement:
If the bone gets displaced as a result of growth &
enlargement of an adjacent bone, it is called “Secondary
displacement.”
e.g.. The growth of the cranial base causes the forward &
downward displacement of the maxilla

11. Characteristics of Bone Growth
Bone formation occurs by 2 methods of differentiation
of mesenchymal tissues that may be of mesodermal or
ectomesenchymal origin.
Accordingly 2 types of bone growth is normally seen.
1) Intra-membranous ossification :
The transformation of mesenchymal connective
tissue usually in membranous sheets, into osseous
tissues.

12. 2. Endochondral ossification:
 The conversion of hyaline cartilage
prototype models into bone.
 The interstitial growth expansion
capability of cartilage, even under weight
pressure due to its avascularity precluding
ischemia,(Cartilage nutrition is provided by per
fusing tissue fluids that are not easily
obstructed by load pressures) allows for
directed prototype cartilage growth.
 The cartilage „template „ is then
replaced by endochondral bone accounting
for indirect bone growth.

13. Growth and development of an individual can be
divided into:-
PRENATAL
&
POSTNATAL periods.
The pre-natal period of development is a dynamic
phase in the development of a human being.
During this period, the height increases by almost
5000 times as compared to only a threefold increase
during the post-natal period.
The pre-natal life can be arbitrarily divided into
three periods.
1. Period of the Ovum
2. Period of the Embryo
3. Period of the Fetus

14. 1. Period of the ovum:
This period extends for a period of approximately two
weeks from the time of fertilization. During this period the
cleavage of the ovum and the attachment of the ovum to the
intra-uterine wall occurs.
2. Period of the embryo:
This period extends from the fourteenth day to the
fifty sixth day of intra-uterine life. During this period the major
part of the development of the facial & the cranial region
occurs.
3. Period of the fetus:
This phase extends between the fifty sixth day of
intra-uterine life till birth. In this period ,accelerated growth of the
cranio-facial structures occurs resulting in an increase in their
size. In addition, a change in proportion between the various
structures also occurs.

15. Prenatal Growth Of Maxilla
Around the fourth week of intra-uterine life, a
prominent bulge appears on the ventral aspect of
the embryo corresponding to the developing
brain.
 Below the bulge a shallow depression which
corresponds to the primitive mouth appears called
“ STOMODEUM”.
The floor of the stomodeum is formed by the
buccopharyngeal membrane which separates
the stomodeum from the foregut

17.  Byaround the 4th week of intra-uterine life, five
branchial arches form in the region of the future head
& neck.
 Each of these arches gives rise to muscles,
connective tissue, vasculature, skeletal components,&
neural components of the future face.

18. The first branchial arch is called the mandibular arch
& plays an important role in the development of the
naso- maxillary region.
 The mesoderm covering the developing forebrain
proliferates & forms a downward projection that
overlaps the upper part of stomodeum .
This downward projection is called “FRONTO-NASAL
PROCESS”.

19. The stomodeum is thus overlapped superiorly by
the fronto-nasal process.
The mandibular arches of both The sides form the
lateral walls of the stomodeum.
The mandibular arch gives off a bud from its dorsal
end called the “MAXILLARY PROCESS”

20. The maxillary process grows ventro-medio-cranial
to the main part of the mandibular arch which is
now called the “MANDIBULAR PROCESS".
Thus at this stage the primitive mouth or
stomodeum is overlapped from above by the
frontal process, below by the mandibular process &
on either side by the maxillary process.

21. The ectoderm overlying the fronto-nasal process
shows bilateral localized thickenings above the
stomodeum.
 These are called the “NASAL PLACODES”. These
placodes soon sink and form the nasal pits.
 The formation of these nasal pits divides the
fronto-nasal process into two parts:
a)The medial nasal process
&
b)The lateral nasal process

23. The two mandibular processes grow medially & fuse
to form the lower lip & lower jaw.
As the maxillary processes undergrows growth, the
fronto-nasal process become narrow so that the two
nasal pits come closer.
 The line of fusion of the maxillary process & the
medial nasal process corresponds to the naso-
lacrimal duct.

24. POST-NATAL GROWTH Of MAXILLA
INTRODUCTION
 Develops from a centre of ossification in the
mesenchyme of the maxillary process.
 No primary cartilage exists.
 Centre of ossification is closely associated with the
cartilage of the nasal capsule.
 Primary centre of ossification develops near the division
of inferior orbital nerve into anterior superior alveolar
nerve (future infra orbital region).

25.  From the centre of ossification the bone formation
extends posteriorly towards the developing zygoma
and anteriorly towards the incisor region
 Ossification spreads superiorly to form the frontal
process of maxilla
 A bony trough is formed for the infra orbital nerve
 From this trough lateral alveolar plate forms for the
developing tooth germs
 Ossification spreads into the palatine processes to form
the hard palate
 Medial alveolar plate develops from the palatal
process
 Medial and lateral alveolar plates form the trough for
the tooth germs

26. POST-NATAL GROWTH Of MAXILLA
 Since, the maxillary complex is attached to the
cranial base, there is a strong influence of the latter
on the former.
 Although there is no sharp line of demarcation
between the cranium & maxillary growth gradients,
yet the position of the maxilla is dependent upon the
growth at spheno-occipital & spheno-ethmoid
synchondroses.
Hence, while discussing the growth of
naso-maxillary complex, we have to look
into two aspects.

27. 1)The displacement in the position
of the maxillary complex
-Secondary displacement-
Occurs in a downward & forward direction
as the cranial base grows.
-Primary displacement-
occurs in a forward direction.
This occurs by growth of the maxillary
tuberosity in a posterior direction .
This results in the whole maxilla being
carried anteriorly.

28. 2) Growth at sutures:
-Sutural connective tissue,
- Proliferation
- Ossification
- Surface apposition
- Resorption
- Translation
are the mechanisms for maxillary growth.
-Maxilla is related to cranium at least partially by the,
-fronto nasal suture
-Fronto maxillary suture
-Zygomaticotemporal suture
-Zygomaticomaxillary suture
-Pterygopalatine suture
These sutures are all oblique & more or less parallel with
each other. The growth in these areas would serve to
move the maxilla downward & forward

30. 3)Surface Remodeling:
Remodeling occurs by bone
deposition & resorption to bring about:
a) Increase in size
b) Change in shape
c) Change in functional relationship

31. Bone remodeling seen in the midfacial region

32. Bone remodeling of the palate resulting in
its downward displacement

33. Growth of the palate exhibiting V pattern of growth

34. The naso-maxillary complex as it emerges from
beneath the cranium

35. SECONDARY CARTILAGE:
 Also known as the zygomatic or the malar cartilage,
appears in developing zygomatic process of maxilla.
 At birth body of maxilla is relatively small as it lacks the
maxillary sinus.
MAXILLARY SINUS:
 Forms during the 16th wk as shallow groove on the nasal
aspect of the developing maxilla.
 Still rudimentary at birth and is that of a size of a pea.

37. Moss Cites three types of bone growth changes to
be observed in the maxilla
1) Those changes that are associated with
compensations for the passive motions of the bone
brought about by the primary expansions of the
orofacial capsule.
2) There are changes in bone morphology associated
with alterations in the absolute volume, size, shape or
spatial position of any or all the several relatively
independent maxillary functional matrices, such as
orbital mass.
3) There are bone changes associated with the
maintenance of the form of the bone itself. All these
changes do not occur simultaneously but rather
differentially or sequentially.

40. The palate “is the tissue that interposes
between the oral & nasal cavities”, it
develops from 2 parts:
the primary palate
&
the secondary palate
Development of the primary palate
( median palatine process, premaxilla)
Appears earlier than 2ry palate at 6wiu.
It is a triangular bone anterior to the incisive
papilla that supports the 4 maxillary incisors.

44. Primary Palate
• Develops from the deep tissues of the
intermaxillary segment during the
deepening of the nasal pit to form the
nasal sac. Tissues beneath the nasal sac
enlarge & grow inferiorly to form the
primary palate.
• It acquires the triangular shape due to
the continuous growth of the maxillary
process in a medial direction.

45. • During the deepening of the nasal sac & the
formation of the primary palate, the ectoderm at
the depth of the nasal sac proliferates to form a
thickened ectodermal plate, the nasal fin, which
then thins down to a thin double thickened
membrane called the “ oro-nasal membrane” ( 2
layers of ectoderm from stomodeum & nasal
sac).
• The rupture of the oronasal membrane detaches
the 1ry palate from the nasal cavity.
• 1ry palate & central parts of upper lip are one
unit at first, then by 8wiu become separated by
the vestibular lamina

46. Development of the secondary palate
• The secondary palate forms the palate
posterior to the incisive fossa that comprises
both the hard & the soft palate.
• The inferior medial edges of the maxillary
process forms the palatine processes
(shelves) at 6wiu.

47. The tongue is narrow & high filling all the
oro-nasal cavity,
so the palatine shelves grow
medially & downwards
(vertically) on either sides of the tongue.

48. Palatal shelf elevation
• The fusion of the palatine shelves occurs
first just posterior to the primary palate.
•From this point, the fusion of the palatine
shelves with premaxilla proceeds anteriorly
& fusion between
between palatine
shelves proceeds
posteriorly.

49. • Fusion also between P shelves & the nasal
septum( formed from the interior parts of the
premaxilla) except posteriorly, where the soft
palate & uvula remain unattached.

50. Hard & soft Palate Formation
• The palate then becomes invaded in its
anterior 2/3 by bone (from premaxillary &
maxillary palatal centers) to form the hard
palate.
• The posterior part becomes invaded by
muscles to form the soft palate
• The incisive suture demarcate the union
between 1ry & 2ry palate, while palatine
raphe demarcate union between 2 palatine
shelves.

51. •Theincisive suture demarcate the union
between 1ry & 2ry palate ( young skulls).
•While palatine raphe demarcate union
between 2 palatine shelves.

52. Developmental anomalies
Cleft Palate
• Less common than cleft lip
• Due to:
1. lack of growth, or failure of fusion between medial &
lateral palatine process & nasal septum.
2. Interruption of the growth after initial fusion ( at any
point).
3. Interference with palatal shelves elevation.

53. Cleft Palate
1. Cleft primary palate
Clefts anterior to incisive Foramen.
Results from Failure of lat. palatine Processes to
meet & fuse With primary palate Associated with
missing or malformed teeth.

54. 2. Clefts secondary palate
• Clefts posterior to incisive foramen.
As fusion of 2ry palate begins at incisive
papilla
& proceeds posteriorly,
The degree of cleft may vary From simplest
form of bifid uvula to a
complete cleft involving both hard & soft
palate.

55. 3. Cleft both primary & secondary palate
• Complete palatal clefts.
Results from :-
failure of growth
Or
lack of fusion of 3 palatine processes
with each other
&
with the nasal septum