Transcript Development of Oro-Facial Structures PowerPoint Presentation File

DEVELOPMENT OF ORO-FACIAL
STRUCTURES AND ITS CLINICAL
CORRELATIONS
The images on slides 9 and 10 are from Thomas A Marino Ph D.
[email protected] while those of 16 and 17 are from a
website. The owner of this website is hereby duly acknowledged. I
also appreciate the contribution of Prof. Cary Engleberg for the
images on slides 5-8.
SLIDE 2: THE INTRODUCTION

The rationale

Methodology

The vision and mission of the Dental School, CHS, KNUST
SLIDE-3: THE LEARNING OUTCOMES

Describe and illustrate the pre-embryonic period of human development,
which is weeks 1-3 (refer slides 3-5)

Describe and illustrate development of branchial arches, the face and palate

Enumerate various types of facial clefts with illustrations

Describe and illustrate development of the tongue

Describe and illustrate development of the mandible, its growth and the fate
of Meckel’s cartilage

Describe and illustrate development of maxilla

Describe derivates and anomalies of branchial arches , clefts and pouches

Diagnose various types of facial clefts images

Self assessments and references
SLIDE 4: PRE-EMBRYONIC WEEK 1
1.
Formation of zygote
2.
The zygote undergoes series of
division to form morula which
differentiates into blastocyst
SLIDE 5: PRE-EMBRYONIC WEEK 1BLASTOCYST DIFFERENTIATION
1.
Thus formed, blastocyst
differentiates into embryoblast
layer and trophoblast layer.
2.
Trophoblats differentiate into
syncytiotrophoblasts and
cytotrophoblasts
SLIDE 6: PRE-EMBRYONIC WEEK 2
1.
At 9th day, blastocyst
completely embedded into
endometrial wall
2.
At days 11 and 12, the
syncytiotrophoblasts erode into
endometrial blood vessels to
establish uteroplacental
circulation
3.
By end of 2nd week, secondary
yolk sac is formed and
amniotic cavity appears
4.
Also, at this time, a bilaminar
embryonic disc forms from
inner cell mass
SLIDE 7: PRE-EMBRYONIC WEEK 3
1.
Formation of trilaminar disc at week
3.
2.
The 3-layered disc named
ectoderm, mesoderm and
ectoderm.
3.
Neural folds formed as a result of
invagination of ectoderm (A and
B).
4.
Population of ectodermal cells
adjacent to the folds gives rise to
neural crest cells (C).
5.
The crestal cells migrate widely (D)
and failure of these cell to migrate
to the face gives rise to Treacher
Collins syndrome
SLIDE 8: THE BRACHIAL ARCHES,
POUCHES AND CLEFTS
1.
Identifiable elements of
brachial apparatus at 5th week
2.
Arrangement of the three
components of brachial
apparatus
3.
A number of adult structures
derivable from the brachial
apparatus (ref slides 16 and 17)
SLIDE 9: THE NERVES OF THE ARCHES
1.
Mandibular div of trigeminal
nerve
2.
The facial nerve
3.
Glossopharyngeal nerve
4.
Vagus and accessory
SLIDE 10: DEVELOPMENT OF THE FACE
AND PALATE
1.
2.
3.
4.
5.
6.
Recognizable face starts from 5
primordia.
Mandibular processes are the fist to
merge.
Formation of Meckel's and
Reichert’s cartilages.
Formation of nasal tip, columella,
prolabium, fraenulum and primary
palate from globular process.
Fusion of maxillary process with
medial fold of globular process.
Development of secondary palate.
SLIDE 11: THE FACE AT 8TH WEEK
By the 8th week, the face has
acquired a more human
appearance with the following
feature in place:
1. Complete closure of lower
facial fissures and grooves
2. Formation of primitive lower
and upper jaws with complete
fusion of max an mand
processes
3. Better definition of upper lip
and lower nasal regions
4. Formation of furrow at the nasal
bridge
SLIDE 12: VARIOUS TYPES OF FACIAL
CLEFTS
SLIDE 13: DEVELOPMENT OF THE
TONGUE


Appearance of a median tongue bud
in the floor of the pharynx at end of
4th week
Formation of lateral tongue buds from
the proliferation of ventromedial 1st
brachial arches

Formation of the anterior 2/3 of the
tongue

Development of posterior 1/3 of the
tongue

The general mucosal sensory
innervations of anterior 2/3

Innervations of the vallate papillae

Innervations of intrinsic and extrinsic
muscles
SLIDE 14-DEVELOPMENT AND GROWTH
OF MANDIBLE AND THE FATE OF
MECKEL'S CARTILAGE



Development of mandible preceded by
meckel’s cartilage which appears in 6th
week
Appearance of mandible as a band of
dense conn. Tissue which ossifies at 7th
week
Mapping of the ramus by condensation
of fibrous tissue far away from the
cartilage

Development of TMJ by mesenchyme
between condyle and temporal bone

Growth of the mandible occurring by
remodelling

Fate of Meckel's cartilage
SLIDE 15-DEVELOPMENT AND GROWTH
OF MAXILLA
1.
2.
Development of maxilla by
intramembraneous ossification
Growth of maxilla
SLIDE 16-DERIVATIVES AND
ANOMALIES OF THE 1ST ARCH, CLEFT
AND POUCH
1.
2.
3.
4.
5.
Derivatives of the mesoderm
of the 1st arch
Anomalies of the mesoderm
of the 1st arch
Derivatives of the ectoderm
of the first brachial cleft
Anomalies of the ectoderm of
the 1st brachial cleft
Development and anomalies
of the 1st brachial pouch
SLIDE 17-DERIVATIVES AND
ANOMALIES OF THE 2ND BRACHIAL
ARCH, CLEFT AND POUCH
1.
2.
3.
4.
Derivatives of 2nd arch (hyoid)
Anomalies of the 2nd arch
Derivatives and anomalies of
the 2nd brachial cleft.
Derivatives and anomalies of
the 2nd brachial pouch
SLIDE 18: DIAGNOSIS OF VARIOUS
TYPES OF ORO-FACIAL CLEFTS
SLIDE 19: SELF ASSESSMENT 1

What is the name of the first pharyngeal arch?

What is the sensory and motor nerve supply of the first pharyngeal
arch?

What is the expression of the second pharyngeal arch on the tongue?

When are the primary and secondary palates formed?

At what age in utero do simple jaw movements commence?

When does the modern TMJ develop?
SLIDE 20: SELF ASSESSMENT 2
7.
How is zygote transported to the uterus?
8.
Name the layers of newly formed blastocyst
9.
What is the embryologic failure that gives rise to Treacher- Collins
syndrome?
10.
What is the site of ossification of maxilla and when does it appear?
SLIDE 21-ANSWERS TO SELF
ASSESSMENTS 1 AND 2
1.
The Mandibular Arch
7.
Ciliary action of the uterine tube
2.
The Trigeminal Nerve
8.
3.
The depression marking the site
of the Thyro-glossal 'duct
Embryoblast the inner layer that
becomes future embryo and the
outer layer, trophoblast
4.
Primary palate at about 6 weeks,
Secondary palate at 8 - 12 weeks
9.
Failure of neural crest cells to
migrate to the face
5.
From about 6+ weeks.
10.
6.
From about 16 weeks in utero,
after secondary cartilage growth
has carried the condylar region
into relationship with the
Temporal bone.
The site of developing deciduous
canine and it appears during the
8th week in utero
SLIDE 22: TEXTBOOKS AND
REFERENCES
1.
2.
3.
4.
5.
6.
7.
8.
Berkovitz BKB, Hollland GR, Moxham BJ. A colour atlas and textbook
of oral anatomy, histology and embryology 2nd Ed 1992; Wolfe
Publishing CO Ltd PP 231-247 or the latest edition if available
Ten-Cate AR. Oral histology, development, structure and function 5th
ed,1998 CV Mosby Co or the latest 6th Edition 2003
Avery JK Essentials of Oral Histology and Embryology A Clinical
Approach 2nd Ed, 2000 C V Mosby Co or the latest edition if available
eMedicine Head and Neck Embryology July 15 2002
Schoen JD, Edmonds JL Brachial anomalies 2003 Texas Paediatric
Otolaryngology Center
eMedicine Face Embryology November 12 2003
Http://www.emedicine.com/ent/topic136.htm
Grays textbook of anatomy-the latest edition if available