Skull, Face, Palate, CN VII Flashcards
anterior portion of skull from
neural crest
posterior portion of skull from
paraxial mesoderm
-somite - sclerotome
fontanelles
soft spots that allow for growth of skull postnatally
allow calvaria to undergo changes during birthing
different fontanelles?
anterior, posterior, posterolateral, anterolateral
flat bones
grow together postnatally
-but cranial sutures remain flexible throughout childhood
craniosynostosis
premature fusion of cranial sutures
scaphocephaly
early fusion of sagittal suture
-skull is long and narrow
- most common
- get sagittal ridge
brachycephaly
early fusion of coronal suture
-skull short and wide
facial prominences
from 1st pharyngeal arch
-form features of face
frontosacral prominence
maxillary prominence
mandibular prominences
give distribution of the trigeminal nerve
-V1, V2, V3**
frontosacral prominence
forehead
bridge nose, septum
medial nasal prominence
lateral nasal prominence
maxillary prominence
upper cheek
lateral portions of upper lip
mandibular prominences
chin, lower cheek region
lower lip
part of external ear
nose formation
nasal placodes
-thickenings of surface ectoderm
form on frontonasal prominence and then invaginate to form nasal pits
nasal placode
thick surface ectoderm
invaginates to form nasal pit
medial and lateral nasal prominences
mesenchyme surrounding margins of nasal pits proliferate
push toward midline
-fuse with eachother**
no fuse, can get midline cleft
intermaxillary segment
two fused nasal prominences that fuse
form upper lip, philthrum, primary palate
midline cleft
two nasal prominences dont fuse
nose from
medial and lateral nasal prominence
and frontonasal prominence
upper lip
from medial nasal prominence and maxillary prominence
lower lip
from mandibular prominences
nasolacrimal duct
maxillary prominence fuse with lateral nasal prominence along nasolacrimal groove
duct forms from ectoderm of the nasolacrimal groove
oblique facial cleft
if maxillary prominence and lateral nasal prominence dont fuse
nasal cavity
nasal pits grow dorsally
- produce nasal sacs
- sacs separated by oronasal membrane
ruptures week 6**
-replaced by palate
olfactory epithelium and CN I
develop from nasal sac ectoderm
paranasal sinuses
slowly develop through puberty
muscles of mastication
first arch
-trigeminal
muscles of facial expression
second arch
-facial arch
primary palate
during 6th week - forms from intermaxillary segment
-fuses with nasal septum above and lateral palatine shelves posteriorly
secondary palate
lateral palatine shelves form from maxillary prominence fuse
incisive foramen
landmark between primary and secondary palates
week 7-8
palatine shelves migrate and fuse with one another as well as with primary palate and in midline with nasal septum
ossification - anterior 2/3 of palate to form hard palate
most common craniofacial anomalies
clefts of lip and palate
anterior cleft
anterior to incisive foramen
failure of maxillary prominence to fuse with medial nasal prominence (intermaxillary segment)
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 with lateral nasal prominences
- mouth towards eye
- nasolacrimal duct not incorporated in face
neural crest defects
craniofacial defects results from disruption of neural crest cell migration or differentiation in face
treacher collins
digeorge anomaly
philthrum derived from?
intermaxillary segment **
