Devlopement of face.pptx

Introduction
Definitions
Growth and development of face
Embryonic devlopment of face
-Gastrulation
-Pharyngeal apparatus
Prenatal and Postnatal devlopment of mandible
Prenatal and postnatal devlopment of maxilla
Summary
References

Introduction
Human beings keep changing during their lives, they change
in size, appearance and psychological make up. The prenatal
growth and development of human embryo is consequence
of increase in number of cells, increase in individual cell
size, increase in amount of noncellular material.

Definitions
“Growth usually refers to an increase in size and number” –
Proffit W. R.
“The Self multiplication of living substance”- J.X.Huxley
“Change in any morphological parameter which is measurable”-
Melvin Moss
“Growth refers to increase in size”– Todd T. Winget
“Increase in size, change in proportion and progressive
complexity” – Krogman W.M.
Proffit W. R. Contemporary orthodontics; 4th edition

 “Development is a progress towards maturity” –
Todd T. Winget
 “Development is in complexity” - Proffit W. R.
 “Development connotes a maturational process
involving progressive differentiation at the cellular
and tissue levels” – Donald H. Enlow
 “Development refers to all naturally occurring,
progressive, unidirectional, sequential changes in life
of an individual from its elaboration as a
multifunctional unit terminating to death” – Moyer R.
E.
Proffit W. R. Contemporary orthodontics; 4th edition

Postnatal
Upper face – Maxilla
Lower face -Mandible
Prenatal
Ovum - Fertilization – 14th day
Embryo - 14th day – 56th day
Fetus - 56th day – 270 days
Human embryology;4th edition; IB Singh

1st Week
Fertilization & Initial implantation
Spermatozoon + Ovum Zygote
3days
Morula Blastula

Completion of implantation
Bilaminar embryonic disc
- Ectoderm
- Endoderm
•Amniotic cavity, Yolk sac,
Connecting stalk formed
•Formation of prochordal plate
Prochordal plate

1) Gastrulation –Formation of 3 germ layers
2) Formation of notochord.
3) Neurulation-Formation of neural tube.
4) Intraembryonic Coelom, blood vessels and blood.

-Ectoderm
-Mesoderm
-Endoderm

Ectoderm
Cutaneos structures
Skin , enamel, oral
mucous membrane,
salivary gland
Neural structures
CNS &PNS
Mesoderm
Cardiovascular system
Heart and blood vessels
Locomotor system
Bones and muscles
Connective tissue
Dental pulp

Endoderm
Lining epithelium of respiratory system & alimentary canal
Secretory cells of liver , pancreas
Epithelium is derived from all three germ layers -
eg. endoderm - epithelial lining inside viscera, mesoderm -
mesothelium lining outside of viscera, and ectoderm - skin
epithelium

Notochord Formation
 Notochord is
flexible rod shape
body. Derive from
mesoderm.
 Form basis of axial
skeleton.
 Extend cranially to
form primitive
node to
buccopharyngeal
membrane.

Neurulation
Neural plates bend up and later fuses to form a hollow tube called neural
tube.
It differentiate into brain and spinal cord of crntral nervous systeme
Neural tube – Brain & Spinal Cord
• Colour atlas of clinical embryology – Keith L. Moore, T.V.N. Persaud, 2nd edition.

Derivatives of Neural crest cells
 Connective tissue components including ectomesenchyme of
facial prominences and pharyngeal arches.
 Cartilage and bones of facial and visceral skeleton, ligaments in
the facial and oral regions.
 Dental papilla, portion of periodontal ligament and pituitary
gland.
 Ciliary muscles.
Craniofacial Development; Sperber

 Spinal ganglia, adrenal medulla, neurolemma sheath,
meningeal covering of brain.
 Autonomic nervous system – sympathetic and
parasympathetic ganglion.
 Blood vessels, carotid body , parafollicular cell and
adrenomedullary cells

The development of the face
occurs mainly between 4 – 8
weeks.
Folding of the embryo.
Primordia of the face appear
at the cephalic end of the
embryo.
Mandible is the first to form.

The stomodeum &
Buccopharyngeal membrane
Five processes have appeared.
-Frontonasal process (1)
-Maxillary processes (2)
-Mandibular processes (2)
Pharyngeal apparatus forms.

Two Nasal placodes
olfactory epithelium and nerve
Two Lense placodes
Ectodermal thickenings
• Colour atlas of clinical embryology – Keith L. Moore, T.V.N. Persaud, 2nd edition.

Pharyngeal apparatus
Begin to develop early in the
4th week
End of 4th week - 4 pairs of
arches
The first arches split into
maxillary and mandibular
prominences.

Pharyngeal arches
Mesodermal thickenings (1, 2, 3,
4 and 6)
Pharyngeal pouches
Endodermal extension in between
two arches
Pharyngeal grooves (clefts)
Ectoderm dips in to meet endoderm
Pharyngeal membranes. Appear
in the floor of grooves

Muscles, Nerves,
Arteries,
Cartilages, Bones
Pharyngeal Arch
Mesoderm, Ectoderm, Endoderm,
Neural crest cells, Cartilaginous rod,
Arterial, Muscular & Nerve
components

1st Muscles of mastication-
- mylohyoid
- tensor veli palitini
-tensor tympani
-anterior belly of the digastric
2nd facial muscles, stylohyoid , stapedius , posterior belly of digastric
3rd Stylopharyngeus muscle
4th
&
Muscles of soft palate muscles of pharynx cricothyroid ,
cricopharyngeus
6th Intrinsic muscles of the larynx , muscles of esophagus

1st Meckel’s cartilage, Malleus,
Incus
2nd Stapes, Styloid process,
Lesser cornu of hyoid bone,Upper part of the body of hyoid
bone
3rd Greater cornu of hyoid bone, lower part the body of hyoid bone
4th & 6th Thyroid cartilage, Cricoid cartilage,
Aryetinoid cartilage
Corniculatecartilage,
Cuneiform cartilage

Nerve & Arteries

Nerves Arteries
1st Trigeminal
(CN V)
Maxillary artery
2nd Facial
(CN VII)
Stapedial artery
3rd Glossopharyngeal
(CN IX)
Common carotid artery,internal
carotid artery
4th Vagus
(CN X) – Superior laryngeal
branch
Rt subclavian artery
Arch of aorta
6th Vagus
(CN X) –Recurrent laryngeal
branch
Pulmonary arteries

1st
Ventral - Tongue
2nd
Dorsal
Dorsal
Tubo-tympanic recess
Ventral - Tonsil
Inferior Parathyroid Gland,
Thymus
3rd
Pharyngeal pouch derivatives

Superior Parathyroid Gland,
Thyroid
4th
5th Ultimobranchial Pouch
Combined with 4th Pouch
1st Groove - External acoustic meatus
1st Membrane - Tympanic membrane

 Formation of nasal pit
-Lateral nasal process
-Medial nasal process
 Maxillary swellings grow
ventrally and medially.
 Nasolacrimal groove
 Eyes derived from –
Neuroectoderm, surface
ectoderm, mesoderm , and
neural crest cells.

Fusion of medial nasal processes.
Fusion of medial & lateral nasal processes
Maxillary prominence begin to merge with the lateral nasal
prominence
The nasal pits deepen-Nasal sac
Mandibular processes fuse.

• Primordia of the auricle forms
1st Pharyngeal groove forms the external acoustic meatus
• Eyelids develop

Intermaxillary process
- Nasal septum
-Philtrum of the upper lip.
-Premaxilla

Fusion of maxillary processes with intermaxillary process
External ear is formed.

Change in the proportion and relative positions of the facial
components.
During the early fetal period, the nose is flat and the mandible is
underdeveloped.

As the brain enlarges, it creates a prominent forehead, the
eyes move medially, and the external ears rise.
Eyelids fuse – 10week
Open – 26th week

Prenatal growth and development of
mandible
oMandible is derived from the 1st branchial arch arises as
bilateral processes that grow ventromedially and fuse in
the midline.
oMandibular process together with maxillary and
frontonasal process bound the
primitive mouth /stomodeum.
oThe cartilages and bones of mandibular skeleton form
from embryonic neural crest cells that originate in the
mid & hind brain region of neural folds.

Mandibular div of trigeminal nerve precedes
ectomesenchymal condensation
Inducing osteogenesis by production of neurotropic factors
Mandibular ectomesenchyme must interact with epithelium of
mandibular arch

Intramembranous bone formation lying lateral to
Meckels cartilage
`
Ossification of osteogenic membrane (formed from
ectomesenchymal condensation at 36-38 days of
development

Meckel's cartilage
It is the cartilage of 1st arch.
At about 6th week (41th-45th day)
of IUL this Meckel's cartilage extend
bilaterally from the otic capsule &
joins in the midline by thin band of
ectomesenchyme.
Disappears by 24th week after
conception.
Remnants of Meckel's cartilage
transformed into various structures.

 Secondary accessory cartilages appear between 10th & 14th week of
IUL to form head of condyle, part of coronoid process & mental
protuberance.
 Condylar cartilage as cone shaped structure in ramal region – 10 th
week of IUL-primordium for future condyle.

 Cartilage Cells of condylar process differentiate
& increase in number.
Ossification starts at 14th week of IUL & first
evidence of endochondral bone appears in
condyle region.

 By mid-fetal life much of
the cone shape cartilage is
replaced by bone ,but its
superior end persists into
adulthood acting as both
growth & articular
cartilage.
 In the mental region 1 or 2
small cartilages appear &
ossify in the 7th month of
post conception to form
mental ossicles on either
side of symphysis.

Postnatal growth and development of
mandible
• Growth of the mandible Is completed 1st width then length and
finally height.
• Width -before aldolescent growth spurt
• Length - Continues through puberty
• Site -
Condylar cartilage – secondary growth
Posterior border of rami
Alveolar ridge
Essentials of facial growth - Enlow and Hans 2nd edition

BODY OF MANDIBLE
• Increase in length of mandibular
body occurs by resorption at
anterior border of ramus.
• This allows growth in
dental arch to accommodate
permanent molar.
• Mandible undergoes rotational
pattern of growth.
• It is depository on outer surface
& resorptive on inferior aspect of
medial surface.
• The superior aspect of medial
surface just below teeth is
depository.

RAMUS UPRIGHTING
• Remodeling of ramus occurs in archial
pattern.
• With anterior displacement condyle
maintains contact with temporal fossa.
• Ramal angle of childhood upright
slightly in adolescence & in late
adulthood it becomes acute.
• Till uprighting, there is deposition at
posterior ramal border but after
uprighting there is selective
deposition/resorption pattern in anterior
& posterior border.
• Along with change in angulation ,there
is also an increase in height of ramus.

Mandibular foramen
Chin
Remodelling changes in the
symphysis is very unique.

ENLOWS V PRINCIPLE
It states that many facial and cranial
bones, or parts of bones, have V shaped
configuration.
According to that bone deposition occurs
at inner side of V and resorption at outer
side of V.
The V thereby moves from point A to B
and at the same time increases in overall
dimensions.
Direction of movement is towards
the wide end of V

Coronoid Process
Deposits on medial surface of coronoid
leads to posterior lengthening of mandible
& also increase in height occurs.
So coronoid also
becomes posteriorly relocated.

lingual tuberosity
Condyle

Prenatal growth and development of maxilla
Maxilla forms within the maxillary
prominences.
Ossification of maxilla begins slightly later
than mandible.
Primary ossification center for each maxilla
in 7th week.
Secondary centers are at zygomatic,
nasopalatine, and orbitonasal area.

Premaxilla ossify from 2 centers
Ossification spreads by : bony trough formed for
infraorbital nerve and palatine process .
Maxillary sinus -16th week

Around 4th week of intra uterine life a prominent
bulge on ventral aspect of embryo appear.
Below that bulge a depression is seen called
stomodeum. Floor is formed by buccopharyngeal
membrane.

The stomodeum is overlap superiorly by frontonasal
process.
The mandibular arch of both side form lateral wall of
stomodeum. Mandibular arch gives off bud from dorsal
end called maxillary process

The ectoderm overlying the fronto-nasal process shows
bilateral localized thickening above stomodeum called
“Nasal placodes”.
This placodes soon sink to form nasal pits.

Fronto-nasal process
Nasal pits
Median nasal Lateral nasal

Postnatal growth and development of maxilla
Maxillary complex is attached to the cranial base. The position of the maxilla is
dependent upon the growth at spheno-occipital & spheno-occipital synchondroses.
1)The displacement in the position of the maxillary complex
Primary displacement –
This occurs by gowth of the maxillary tuberosity in a posterior direction .This results in the
whole maxilla being carried anteriorly.
Secondary displacement-
Occurs in a Downward & forward direction as the cranial base grow .

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 Sutures
These sutures are all oblique & more or les parallel with each other.The growth in
these areas would serve to move the maxilla downward & forward.

3)Surface Remodeling:
Remodeling occurs by bone deosition & resorption.
Bone remodeling seen in the midfacial region

Bone remodeling of the palate resulting in its downward
displacement

Growth of the palate exhibiting V pattern of growth

Development of Palate
Palatogenesis start at end of 5th till 12th week
Two premordia : Primary palate
Secondary palate

Primary palate
Developes from deep part of
inter maxillary segment of
maxilla.
Develops end of 5th week
Internal merging of medial
nasal process
Secondary palate
Primordium of hard and
soft palate posterior to
incisive foramen.
Develops 6th week from
Lateral palatine processes
of maxillary prominence.

The palatine process fuse In midline and with
Nasal septum And posterior part of Primary
palate.

 Frontal prominence
Forehead ,bridge of the nose,
dorsum of the nose
Frontal and nasal bones
 Maxillary prominences
Upper cheek regions,most of
the upper lip except philtrun
Maxilla, zygomatic bone,
secondary palate
 Lateral nasal prominences
Alae of the nose
Grays anatomy;39th edition; Starding Susan

Mandibular prominences
Chin, lower lip, and lower
cheek regions
Mandible
The medial nasal prominences
fuse
Intermaxillary segment – Nasal
septum Philtrum, Primary
palate

The size of the embryo from fertilization to 8th week
Length of embryo
4th Week of IU – 5mm
8th Week – 30mm
Full term – 300mm

Summary
•We have seen how an every individual spends first 9
months of his or her life in it’s mother’s womb, from the
day of inception as a single cell strucure to an organism
having billions of cells, numerous tissues and organs which
are functioning in a perfect harmony

References
• Colour atlas of clinical embryology – Keith L. Moore, T.V.N.
Persaud, 2nd edition.
• Human embryology;4th edition; IB Singh
• Craniofacial Development; Sperber
• Oral anatomy, histology and embryology ;3rd edition; Berkovitz
• Oral Histology,Development,Structure and Function.5th
edition;A.R.Tencate:Mosby
• Orban’s Oral Histology and Embryology.11th edition;Mosby
• Grays anatomy;39th edition; Starding Susan
• Anatomy; vol 3; 3rd edition; B.D.Chaurasia
• Proffit W. R. Contemporary orthodontics; 4th edition
• Essentials of facial growth - Enlow and Hans 2nd edition

Devlopement of face.pptx

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