Development of Face and Palate

maxillary prominences form

• upper cheek

• lateral upper lip

mandibular prominences form

• chin

• lower lip

• lower jaw

• lower cheek

frontonasal prominence forms

• forehead and bridge of nose

• philtrum of upper lip

nasolacrimal groove forms

• nasolacrimal duct

• lacrimal sac

auricular hillocks form

external ear

first pharyngeal groove forms

external acoustic meatus

facial development occurs mainly during

weeks 4-8

external ears form at

boundary between pharyngeal arches 1 and 2

nasal placodes sink into

nasal pits— precursors of nostrils and nasal cavities

lateral nasal prominences form

sides of nose

medial nasal prominences form

• nasalseptum

• part of ethmoid bone

medial nasal prominences fuse with

each other and with maxillary prominences

nasolacrimal grooves separate

lateral nasal prominences from maxillary prominences

by the end of week 5

six auricular hillocks indicate development of external ear

external ears’ location

• initially neck region

• ascend to sides of head at eye level

first arch syndrome

• insufficient migration of neural crest cells into 1st arch

• two manifestations: Treacher-Collins and Pierre-Syndrome

treacher-collins syndrome

• underdevelopment of zygomatic bones

• down-slanting palpebral fissures

• deformed external ears

• abnormal middle and internal ears

pierre-robin syndrome

• hypoplasia of mandible

• bilateral cleft palate

• defects of eye and ear

primary palate

• median palatal process develops from merged medial nasal prominences at 6 weeks

• premaxillary part of hard palate

• anterior to incisive fossa

secondary palate

• two lateral palatal processes develop from internal aspects of maxillary prominences at 6 weeks

• soft palate

• hard palate posterior to incisive fossa

formation of upper lip

medial nasal prominences fuse with each other, and with maxillary prominences

philtrum of lip and median palatal process form from

intermaxillary segment (fused portion of medial nasal prominences)

fusion of lateral palatine processes in midline create

posterior hard palate and soft palate

during development of secondary palate from lateral palatal processes

oral cavity is separated from nasal cavity

clefts can be

unilateral or bilateral