FacialFacial andand palatalpalatal developmentdevelopment

L.MossL.Moss--SalentijnSalentijn TimelineTimeline forfor developmentdevelopment

Secondary Completion of soft palate

Primary palate

External face Pharyngeal arches

4 wks 6 wks 8 wks 12 wks

Decrease of severity of potential congenital malformations ContributionsContributions toto thethe externalexternal faceface

„ PeriprosencephalonPeriprosencephalon:: ectodermectoderm andand mostlymostly ncnc-- derivedderived mesenchymemesenchyme surroundingsurrounding thethe forebrain.forebrain. FrontonasalFrontonasal process.process. „ FirstFirst pharyngealpharyngeal ((mandibularmandibular)) arch.arch. MandibularMandibular andand maxillarymaxillary processes.processes. ContributionsContributions toto externalexternal faceface

Moss-Salentijn L, Klyvert M (1990) OropharyngealOropharyngeal membranemembrane ((buccopharyngealbuccopharyngeal,, oral)oral) Tuchmann-Duplessis H, David G, Haegel P (1975)

Waterman RE, Schoenwolf GC (1980)

MembraneMembrane isis composedcomposed ofof ectodermectoderm andand endodermendoderm DisintegrationDisintegration ofof oropharyngealoropharyngeal membranemembrane

Waterman RE, Schoenwolf GC (1980)

CommunicationCommunication betweenbetween foregutforegut andand amnioticamniotic cavitycavity atat approximatelyapproximately 44 weeksweeks ofof developmentdevelopment StomodeumStomodeum atat 44 weeksweeks

Waterman RE, Schoenwolf GC (1980) FacialFacial processesprocesses (prominences)(prominences)

Bilaterally:Bilaterally: LateralLateral nasalnasal MedialMedial nasalnasal MaxillaryMaxillary MandibularMandibular

Sulik K, Johnston M et al (1980) FaceFace developmentdevelopment animationanimation 11

Watt, Marie A, and Sanders, Colin FaceFace developmentdevelopment –– animationanimation 22 Watt, Marie A, and Sanders, Colin DevelopmentDevelopment externalexternal faceface (4(4--55 wks)wks) DevelopmentDevelopment externalexternal faceface (6(6--88 wks)wks) Gasser R (2006) DimensionalDimensional changeschanges (4(4--66 wks)wks)

Moss-Salentijn L et al (1972) 1010--foldfold linearlinear increaseincrease inin sizesize !!

Moss-Salentijn L et al (1972) MergingMerging

DifferentialDifferential mesenchymalmesenchymal proliferation.proliferation. EliminationElimination ofof groove.groove.

Ten Cate AR (1988) MergingMerging withwith epithelialepithelial inclusioninclusion

MayMay resultresult inin facialfacial cleft.cleft.

MayMay bebe normalnormal betweenbetween LNPLNP andand maxillarymaxillary processprocess wherewhere enclosedenclosed epitheliumepithelium givesgives riserise toto partpart ofof nasolacrimalnasolacrimal ductduct epithelium.epithelium.

Millicovsky G, Johnston MC (1981) Nasolacrimal duct between maxillary and lateral nasal processes SitesSites ofof potentialpotential facialfacial cleftsclefts

Moss-Salentijn L, Klyvert M (1990) FusionFusion

ContactContact andand fusionfusion ofof epitheliumepithelium-- coveredcovered surfaces.surfaces. RemovalRemoval ofof epitheliumepithelium

Ten Cate AR (1988) FusionFusion inin primaryprimary andand secondarysecondary palatepalate developmentdevelopment

Sun D, Baur S, Hay ED (2000) FateFate ofof fusedfused epitheliumepithelium

„„ NonNon--proliferatingproliferating epitheliumepithelium inin rapidlyrapidly growinggrowing environment:environment: passivepassive stretchstretch andand incorporationincorporation inin nearbynearby surfacesurface epitheliaepithelia „„ ApoptosisApoptosis andand phagocytosisphagocytosis „„ EpithelialEpithelial--mesenchymalmesenchymal transformationtransformation DevelopmentDevelopment ofof nosenose InitialInitial fusionfusion ofof medialmedial andand laterallateral nasalnasal processes,processes, andand subsequentlysubsequently betweenbetween medialmedial nasalnasal andand maxillarymaxillary processes.processes. Millicovsky G, Johnston MC (1981) Otto H-D, Opitz Ch (1987)

AllAll epitheliumepithelium inin fusionfusion lineline isis removedremoved exceptexcept oronasaloronasal membranemembrane (ectoderm(ectoderm--ectoderm)ectoderm)

Tuchmann-Duplessis H, Haegel P (1975) Watt, Marie A, and Sanders Colin, Univ Glasgow OronasalOronasal membranemembrane

BreaksBreaks downdown atat aboutabout 66 wkswks ofof development.development.

Tamarin A (1982) PrimaryPrimary (primitive)(primitive) palatepalate

Tamarin A (1982)

Primary palate composed of: intermaxillary segment of merged MNP’s and the rostral tips of the maxillary processes. P: primary (primitive) choana permitting oro-nasal communication DevelopmentDevelopment ofof primaryprimary andand secondarysecondary palatepalate

Langman J Medical

SecondarySecondary palatepalate developmentdevelopment Chai Y, Maxson RE (2006) IntrinsicIntrinsic factorsfactors inin thethe successfulsuccessful developmentdevelopment ofof thethe secondarysecondary palate:palate: increaseincrease inin sizesize ofof palatalpalatal processesprocesses

„ MesenchymalMesenchymal cellcell proliferationproliferation –– ceasesceases hourshours beforebefore palatalpalatal processesprocesses becomebecome horizontalhorizontal „ ECMECM productionproduction increasingincreasing volumevolume ofof palatalpalatal processesprocesses „ HydrationHydration ofof ECMECM –– majormajor increaseincrease inin volumevolume andand turgorturgor justjust priorprior toto horizontalizationhorizontalization SecondarySecondary palatepalate developmentdevelopment

Waterman RE, Meller SM (1974) Palatal processes develop on the oral surfaces of the maxillary processes: initially vertically oriented, they assume horizontal orientation during eighth week of development. HorizontalizationHorizontalization ofof palatalpalatal processesprocesses

Watt, Marie A, and Sanders, Colin FactorsFactors contributingcontributing toto thethe horizontalizationhorizontalization ofof thethe palatalpalatal processesprocesses „ TurgorTurgor inin thethe palatalpalatal processesprocesses „ MovementsMovements ofof thethe tonguetongue –– primitiveprimitive swallowingswallowing-- allowingallowing tonguetongue toto movemove outout ofof thethe wayway „ DownwardDownward andand forwardforward growthgrowth ofof lowerlower jawjaw complexcomplex –– providingproviding spacespace forfor thethe secondarysecondary palatepalate „ StraighteningStraightening ofof thethe cranialcranial basebase –– providingproviding mechanicalmechanical conditionsconditions forfor horizontalizationhorizontalization Barteczko K, Jacob M (2004) Moss-Salentijn L et al (1972) FactorsFactors contributingcontributing toto thethe successfulsuccessful fusionfusion ofof thethe secondarysecondary palate:palate: thethe medialmedial edgeedge epitheliumepithelium (MEE)(MEE)

„ ApoptosisApoptosis ofof MEEMEE surfacesurface cellscells immediatelyimmediately priorprior toto fusionfusion „ DevelopmentDevelopment ofof temporarytemporary glycoproteinglycoprotein membranemembrane coating,coating, enablingenabling adhesionadhesion betweenbetween MEEMEE cellscells ofof opposingopposing palatalpalatal processesprocesses „ SuccessfulSuccessful removalremoval ofof MEEMEE fromfrom fusionfusion lineline Mori C, et al. (1994)

Fate of MEE cells: apoptosis (TUNEL reaction above) and Schupbach PM, Schroeder HE (1983) phagocytosis CompletionCompletion ofof palatepalate formationformation

Waterman RE, Meller SM (1974) Chai Y, Maxson RE (2006) SitesSites ofof potentialpotential palatalpalatal cleftsclefts

Langman J, Medical Embryology