skull, face, palate Flashcards
skull development
ant from neural crest
post from paraxial mesoderm
fontanelles
ant, post, posterolateral, anterolateral
craniosynostosis
premature fusion of cranial sutures
scaphocephaly- most common, skull low and narrow
brachycephaly- second most common, early fusion of coronal suture, skull short and wide
frontonasal prominence
3 paired facial prominences from 1st arch form:
frontonasal prominence
maxillary prominence
mandibular prominence
frontonasal prominence
forehead
bridge of nose and nasal septum
medial nasal prominences- apex of nose, philtrum of upper lip
lateral nasal prominences- ala of nose
maxillary prominence
upper cheek
lateral portion upper lip
mandibular prominences
chin
lower cheek region
lower lip
part of external ear
nasal placodes
thickening of surface ectoderm form on frontonasal prominence and invaginate to form nasal pits
development from nasal pits
mesenchyme surrounding pits proliferates to form the medial and lateral nasal prominences
medial nasal prominences fuse forming intermaxillary segment
intermaxillary segment
intermaxillary segment then fuses will adjacent maxillary prominence to form upper lip
intermaxillary segement also gives rise to philtrum and primary plate
upper lip
from medial nasal prominences and maxillary prominences
lower lip
mandibular prominences
nasolacrimal duct
maxillary prominence fuses w/lateral nasal prominence along nasolacrimal groove
nasolacrimal duct forms from ectoderm of nasolacrimal groove
nasal cavities
nasal pits deepen and grow dorsally, produce nasal sacs
nasal sacs are separated from oral cavity by oronasal membrane (ruptures wk 6th and replaces by palate)
olfactory epi and CNI develop from nasal sac ectoderm
paranasal sinuses
develop throughout puberty
primary palate
during wk 6 primary palate froms from intermaxillary segment
fuses w/nasal septum above and lateral palatine shelves posteriorly
secondary palate
lateral palatine shelves form from maxillary prominences
initially palatine shelves project inferomedially on each side of tongue
during wks 7-8 palatine shelves migrate superiorly and fuse with each other, the primary palate, and in midline w/nasal septum
ossification occurs in ant 2/3s of palate to form hard palate
incisive foramen in land mark btwn primary and secondary palates
anterior cleft
extends through lip, alveolar part of maxilla to incisive fossa
caused by failure of maxillary prominence to fuse w/medial nasal prominence
median cleft of lip
failure of medial nasal prominences to merge, rare
posterior cleft
lack of fusion of lateral palatine plates
cleft palate and or uvula
oblique facial cleft
failure of maxillary process to fuse w/lateral plate prominence
runs from mouth towards eye, results in nasolacrimal duct not being incorporated into face
