development of orofacial region
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DEVELOPMENT OFDEVELOPMENT OF
OROFACIAL REGIONOROFACIAL REGION
Oral HistologyOral Histology
Dent 206Dent 206
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Folding of the embryoFolding of the embryo
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Branchial ArchesBranchial Arches
Buccopharyngeal membraneBuccopharyngeal membraneruptures @ 21 daysruptures @ 21 days Stomodeum (primitive mouth)Stomodeum (primitive mouth)
Branchial (pharyngeal) pouchesBranchial (pharyngeal) pouches
Branchial (pharyngeal) cleftsBranchial (pharyngeal) clefts
Branchial (pharyngeal) archesBranchial (pharyngeal) arches
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Branchial archesBranchial arches
28 days26 days
28 days32 days
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Branchial archesBranchial arches
Embryologic basis of all the differentiatedEmbryologic basis of all the differentiatedstructures of the head and neckstructures of the head and neck
5 pairs of branchial arches appear on day 225 pairs of branchial arches appear on day 22
Correspond to the primitive vertebrae gillCorrespond to the primitive vertebrae gillbarsbars
On either side of the pharyngeal foregutOn either side of the pharyngeal foregut
Each arch consists of 3 layersEach arch consists of 3 layers
Outercovering of ectodermOutercovering of ectoderm
Innercovering of endoderm,Innercovering of endoderm,
Middle core of mesenchyme.Middle core of mesenchyme.
Arches are separated further intoArches are separated further into
External, ectodermExternal, ectoderm--lined pharyngeal cleftslined pharyngeal clefts
Internal, endodermInternal, endoderm--lined pharyngeal poucheslined pharyngeal pouches
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Branchial archesBranchial arches
First stages of a recognizable face at the end ofFirst stages of a recognizable face at the end ofthe third weekthe third week
Frontal nasal process (cephalic portion of theFrontal nasal process (cephalic portion of theneural tube)neural tube)
Branchial archesBranchial arches
Over weeks, the arches grow differentially andOver weeks, the arches grow differentially and
obliterate plates/grooves to give rise to the faceobliterate plates/grooves to give rise to the face Each arch gives rise to a cranial nerve, musclesEach arch gives rise to a cranial nerve, muscles
and cartilage/boneand cartilage/bone
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Branchial archesBranchial arches
Each branchial arch hasEach branchial arch has
Skeletal elementsS
keletal elements
Nervous elementsNervous elements
Muscular elementsMuscular elements
Vascular elementsVascular elements
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Skeletal elementsSkeletal elements
First archFirst arch Meckels cartilageMeckels cartilage
Anterior partAnterior part
Doesnt form the body of theDoesnt form the body of the
mandiblemandible
Act as a scaffold for the body ofAct as a scaffold for the body of
the mandible to form at its lateralthe mandible to form at its lateral
aspectaspect
Disappears finallyDisappears finally
Middle partMiddle part
Anterior malleolar ligamentAnterior malleolar ligament
Sphenomandibular ligamentSphenomandibular ligament
Dorsal endDorsal end -- MalleusMalleus
Pterygoquadrate barcartilagePterygoquadrate barcartilage
IncusIncus
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Skeletal elementsSkeletal elements
Second archSecond arch
Reicherts cartilageReicherts cartilage
Dorsal endDorsal end -- StapesStapes
RemainderRemainder
Styloid processStyloid process andand stylohyoid ligamentstylohyoid ligament
Hyoid boneHyoid bone except greater hornexcept greater horn
Third archThird arch -- Greater horn of hyoidGreater horn of hyoid
Fourth to sixth archesFourth to sixth arches Thyroid, cricoid &Thyroid, cricoid &
arytenoid cartilagesarytenoid cartilages
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Nervous elementsNervous elements
First archFirst arch
Trigeminal nerve (V)Trigeminal nerve (V)
Second archSecond arch Facial nerve (VII)Facial nerve (VII)
Third archThird arch
Glossopharungeal (IX)Glossophar
ungeal (IX)
Fourth to sixth archesFourth to sixth arches
Vagus nerve (laryngealVagus nerve (laryngeal
branches)branches)
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Muscular elementsMuscular elements
First archFirst arch Muscles innervated byMuscles innervated by trigeminal nervetrigeminal nerve
Muscles of masticationMuscles of mastication
Anterior belly of digastricAnterior belly of digastric
MylohyoidMylohyoid
Tensor tympaniTensor tympani
Tensor veli palatiniTensor veli palatini
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Muscular elementsMuscular elements Second archSecond arch
Muscles innervated byMuscles innervated by facial nervefacial nerve Muscles of facial expressionMuscles of facial expression
Posterior belly of digastricPosterior belly of digastric
Third archThird arch Muscles innervated byMuscles innervated byglossopharyngealglossopharyngeal
nervenerve Palatopharyngeus musclePalatopharyngeus muscle
Fourth to sixth archesFourth to sixth arches Muscles innervated by the pharyngeal branchMuscles innervated by the pharyngeal branch
ofofVagusVagus nervenerve
All muscles of the pharynx exceptAll muscles of the pharynx exceptpalatopharyngeuspalatopharyngeus
All muscles of the soft palate except tensorAll muscles of the soft palate except tensorveli palatiniveli palatini
Muscles innervated by the laryngealMuscles innervated by the laryngealbranches ofbranches ofVagusVagus nervenerve
Intrinsic laryngeal musclesIntrinsic laryngeal muscles
Extrinsic laryngeal musclesExtrinsic laryngeal muscles
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Vascular elementsVascular elements
Each archEach arch right & left aortic arch vesselright & left aortic arch vessel
Leads from the heartLeads from the heart
Ascends dorsally to the face, brain & posterior region ofAscends dorsally to the face, brain & posterior region of
the bodythe body
Third arch vessel becomes prominent to take over the facialThird arch vessel becomes prominent to take over the facial
region of the first tworegion of the first two common carotid arterycommon carotid artery
Fourth arch vesselFourth arch vessel dorsal aortadorsal aorta
Blood supply for neck& faceBlood supply for neck& face Before weeksevenBefore weekseven internal carotidinternal carotid
After weeksevenAfter weekseven external carotidexternal carotid
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Vascular elementsVascular elements
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Pharyngeal pouchesPharyngeal pouches
Tongue formationTongue formation Appears @ 32 daysAppears @ 32 days
Develops fromDevelops from Swellings from 1Swellings from 1stst arch (anterior 2/3s)arch (anterior 2/3s)
Lateral swellingsLateral swellings Tuberculum imparTuberculum impar
Swelling from 3Swelling from 3rdrd (posterior 1/3)(posterior 1/3) Copula/Hypobranchial eminenceCopula/Hypobranchial eminence
Overgrows 2Overgrows 2ndnd archarch
Swelling from 4Swelling from 4thth arch (extremearch (extreme
posterior)posterior) EpiglottisEpiglottis
Sulcus terminalisSulcus terminalis
Foramen cecumForamen cecum Thyroglossal ductThyroglossal duct
Thyroid glandsThyroid glands
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Innervation of the tongueInnervation of the tongue Anterior 2/3sAnterior 2/3s
SensorySensory First arch nerve (trigeminal throughFirst arch nerve (trigeminal through
lingual nerve)lingual nerve)
TasteTaste Facial nerve through chordaFacial nerve through chorda
tympanitympani
Glossopharyngeal (Vallate papillaeGlossopharyngeal (Vallate papillaemigration)migration)
MotorMotor Hypoglossal nerve XII (muscles ofHypoglossal nerve XII (muscles of
the tongue are from myotomes ofthe tongue are from myotomes ofmetotic somites)metotic somites)
Posterior 1/3Posterior 1/3 Sensory and tasteSensory and taste
Third arch nerve (glossopharngeal)Third arch nerve (glossopharngeal)
Extreme posteriorExtreme posterior Sensory and tasteSensory and taste
Fourth arch nerve (SuperiorFourth arch nerve (Superiorlaryngeal nerve)laryngeal nerve)
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Development of the faceDevelopment of the face
Growth ofGrowth of
Maxillary processesMaxillary processes
Mandibular pro
cessesMandib
ular pro
cesses
Frontonasal processFrontonasal process
47 days
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Development of the faceDevelopment of the face
Face forms around stomodeumFace forms around stomodeum
Buccopharyngeal membrane ruptures @ 21Buccopharyngeal membrane ruptures @ 21
daysdays Mesodermal processesMesodermal processes
Nasolacrimal ductNasolacrimal duct
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Frontonasal process (unpaired)Frontonasal process (unpaired)
Nasal placodesNasal placodes
Nasal pitNasal pit -- nostrilsnostrils
Medial nasal swellings (togetherMedial nasal swellings (together -- Intermax
illaryIntermax
illarysigment)sigment)
Mid portion of the noseMid portion of the nose
Philtrum ofupper lipPhiltrum ofupper lip
Primary palatePrimary palate lateral nasal swellingslateral nasal swellings
Alae of the noseAlae of the nose
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11stst arch processes (paired)arch processes (paired)
Maxillary processesMaxillary processes
Much of the maxillaMuch of the maxilla
Lateral parts ofupper lipLateral parts ofupper lip
Mandibular processesMandibular processes
MandibleMandible
Lower lipLower lip
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Nasolacrimal ductNasolacrimal duct
Forms between lateral nasal swellings andForms between lateral nasal swellings and
maxillary processmaxillary process
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PalatePalate
Starts @ 6 weeksStarts @ 6 weeks
Primary palatePrimary palate
Secondary palateSecondary palate
Palatine processesPalatine processes
11stst they are verticallythey are verticallyorientedoriented
Tongue in betweenTongue in between
Horizontal reorientationHorizontal reorientation
Fusion with primary palateFusion with primary palate
Fusion with ea
ch other
Fusion with ea
ch other
Fusion with nasal septumFusion with nasal septum
Palate completed by 60Palate completed by 60daysdays
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CleftsClefts
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Development of the maxillaDevelopment of the maxilla
MaxillaMaxilla Membranous ossificationMembranous ossification
2 ossification centres2 ossification centres
Maxilla properMaxilla proper
Ossification starts at 40 daysOssification starts at 40 days
Maxillary sinusMaxillary sinus
PremaxillaPremaxilla
Ossifies later than maxillaOssifies later than maxilla
ProcessesProcesses
FrontalFrontal
ZygomaticZygomatic
PalatinePalatine
Medial & lateral alveolarMedial & lateral alveolarplatesplates
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Development of the mandibleDevelopment of the mandible
Development of bodyDevelopment of body
Development of ramusDevelopment of ramus
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Development of bodyDevelopment of body
Membranous ossificationMembranous ossification
Close association with Meckels cartilageClose association with Meckels cartilage
Ossification starts atOssification starts at 7 weeks7 weeks At the site where mental nerve branches offAt the site where mental nerve branches off
Continues around IANContinues around IAN
Alveolar processAlveolar process
Symphasis mentiSymphasis menti Fuses at 1Fuses at 1ststpostnatal yrpostnatal yr
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Development of ramusDevelopment of ramus
EndochondralEndochondralossificationossification
CondylarcartilageCondylarcartilage
Appears at 11 weeksAppears at 11 weeks Growth until 21 yrsGrowth until 21 yrs
Coronoid cartilageCoronoid cartilage 14 weeks14 weeks
Replaced by boneReplaced by bonebefore birthbefore birth
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Mandiblular unitsMandiblular units
UnitsUnits
CondylarCondylar
BodyBody
AngularAngular forms informs inresponse toresponse to
Medial pterygoidMedial pterygoid
MasseterMasseter
CoronoidCoronoid forms informs inresponse to temporalisresponse to temporalis
AlveolarAlveolar
Forms in response to teethForms in response to teeth