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In the name of GOD
Prenatal Facial Growth and Development
Presented by:
Dr Somayeh Heidari
Orthodontist
Reference:
Textbook of Orthodontics
chapter 1
Samir E. Bishara. 2001. Saunders
Terminology
Growth:
refers to an increase in size or number
an anatomic phenomenon
quantitative in nature
Development:
refers to an increase in complexity
increasing specialization
loss of potential
physiologic and behavioral
qualitative in nature
Endochondral bone formation:
osteoblasts deposit bone matrix around cartilage model that
formed by chondroblasts. cartilage matrix is eventually lost
Endochondral bone formation:
Cranial base, Mandibular condyle
Cartilage
Bone
Intramembranous bone formation:
direct secretion of bone matrix within connective tissues
Cranial vault, Maxilla and
body of Mandible
Deposition: the biological process of laying down the bone
Resorption: the biological process of removing the bone
Remodeling: A basic part of bone growth involves simultaneous
deposition and resorption on all inner and outer surfaces of the
entire bone. It provides regional changes in
shape, size, and proportions
Facial growth and development
I: Prenatal
4 weeks embryo
Pharyngeal (Branchial) apparatus
• Pharyngeal arch
• Pharyngeal pouch
• Pharyngeal cleft
• Pharyngeal membrane
Endoderm
Artery
Nerve
Cartilage
mesoderm
Mesenchyme
Neural crest
Pharyngeal cleft
Pharyngeal membrane
Ectoderm
Pharyngeal arches
Pharyngeal arches components
 cranial nerves
 skeletal components
 muscular components
 arterial components
Pharyngeal arches cranial nerves
I: Trigeminal nerve (V)
maxillary
mandibular
II: Facial nerve (VII)
III: Glossopharyngeal nerve (IX)
IV : Vagus nerve (X)
superior laryngeal
VI: Vagus nerve (X)
recurrent laryngeal
Pharyngeal arches cranial nerves
Skeletal derivatives
I: zygomatic bone
maxilla
squamous process
(intramembranous ossification)
Skeletal derivatives
I: Meckel cartilage
mandible
incus
malleus
sphenomandibular ligament
Skeletal derivatives
II: Reichert
stapes
styloid process
upper part of hyoid body
lesser horn of hyoid
stylohyoid ligament
Skeletal derivatives
III: greater horn of hyoid
inferior part oh hyoid body
IV and VI: laryngeal cartilages:
thyroid
cricoid
arytenoid
Muscular derivatives
I: msseter
temporalis
internal ptrygoid
external ptrygoid
anterior belly of digastric
myelohyoid
tensor veli palatini
tensor tympani
Muscular derivatives
II: facial expression muscels
frontal
orbicularis oris
orbicularis oculi
zygomaticus
platysma,…
stapedius
styloid
posterior belly of digastric
Muscular derivatives
III: stylopharyngeus
IV: cricothyroid
VI: internal laryngeal muscles
Arterial derivatives
I: maxillary artery
II: hyoid artery
stapedial artery
III: part of common carotid
Arterial derivatives
IV: left – part of arcus aortae
right – subclavian artery
VI: part of pulmonary arteries
Derivatives of pharyngeal arches
Pharyngeal pouches
Pharyngeal pouches
I:
•
tympanic cavity
•
pharyngotympanc tube
(auditory or eustachian tube)
•
mastoid antrum
Pharyngeal pouches
II: palatin tonsil
III: inferior parathyroid glands
thymus
Pharyngeal pouches
IV: superior parathyroid glands
ultimobranchial body
(parafollicular cells of thyroid gland)
Pharyngeal clefts (grooves)
I: external auditory meatus
II: cervicular sinus
Pharyngeal fistula
Pharyngeal membrane
I: tympanic membrane
Development of face
facial primordia appear at the end of 4th week (neural crest
ectomesenchyme of 1st pharyngeal arch) around stomodeum
•frontonasal prominence cranially
•maxillary prominences laterally
•mandibular prominences caudally
on each side develop bilateral oval thickenings of the
surface ectoderm  nasal placodes
they depress within 5th week  nasal pits
pits are bordered by horseshoe-shaped elevations →
medial and lateral nasal prominences
maxillary prominences enlarge (cheeks and upper jaw) and growth
medially
pressing medial nasal prominences to the midline → then they merge
upper lip is formed by the maxillary prominences and medial nasal
prominences
lower lip and jaw are formed by mandibular prominences that merge in
the midline
nose arises from 5 sources:
frontonasal prominence
2 medial nasal prominences
2 lateral nasal prominences
development of palate
primary palate
by merging of both medial nasal prominences:
lip component  philtrum
component for the upper jaw (carries 4 incisors)
palatine component (forms the primary palate)
passes continuously into nasal septum
secondary palate
by merging of palatine processes of maxillary
process (6th week)
ventrally fusion with
primary palate
Cleft
Tongue development
skull development
Neurocranium
Endochondral ossification
• calvaria
• base of skull
+
Intramembranous ossification
viscerocranium
Chondro-neurocranium
synchondroes
Membranous- neurocranium
sutures
fontanells
Viscerocranium
Thanks for your attention