Skull Face palate Flashcards
the anterior portion of the skull is derived form what
neural crest
the posterior portion of the skull is derived from what
paraxial mesoderm
What causes craniosynostosis
premature fusion of cranial sutures
What is Scaphocephaly
early fusion of sagittal suture
Skull has long AP axis and narrow transverse
what is brachycephaly
early fusion of coronal suture
skull is short AP axis and wide transverse
What are the 3 facial prominences and what are they derived from
frontonasal prominence
maxillary prominence
mandibular prominence
all from the 1st arch
what makes up frontonasal prominence
forehead, bridge of nose and nasal septum
medial nasal prominences
lateral nasal prominences
what are the medial nasal prominences
apex of nose, philtrum of upper lip
what are the lateral nasal prominences
ala of nose
What are the maxillary prominences
upper cheek
lateral portions of upper lip
what are the mandibular prominences
chin, lower cheek
lower lip
part of external ear
What forms the nasal pits
nasal placodes form on frontonasal prominence then invaginate
what are the nasal placodes
thickening of surface ectoderm
What are the medial and lateral nasal prominences dervided from
mesenchyme
What is the intermaxillary segment
when the medial nasal prominences are fused at midline
what does the inter maxillary segment give rise to
fuse to adjacent maxillary prominence to form upper lip
also gives rise to philtrum and primary palate
Describe formation of the nasolacrimal duct
maxillary prominence fuses with lateral nasal prominence along nasolacrimal groove
then the duct forms from the ectoderm of this groove
Describe formation of nasal cavities
nasal pits deepen and grow dorsally to produce nasal sacs which are separated from oral cavity by oronasal membrane
when does the oronasal membrane rupture
week 6 and replaced by palate
What structures develop from nasal sac ectoderm
olfactory epithelium and CN I
Describe formation of primary palate
6th week is forms from intermaxillary segment and fuses with the nasal septum above and lateral palatine shelves posteriorly
describe formation of the secondary palate
lateral palatine shelves form from maxillary prominences
palatine shelves project inferomedially on each side of tongue
weeks 7-8 migrate superiorly and fuse together with primary palate and midline nasaal septum
What is the hard palate from
when the anterior 2/3 of palate ossifies
the incisive foramen is a landmark between what
primary and secondary palates
What are the most common craniofacial anomalies
clefts of lip and palate
where is an anterior cleft and what causes it
anterior to incisive foramen
complete anterior cleft extends through lip
alveolar part of maxilla to incisive fossa
separates primary from secondary palate
caused by failure of maxillary prominence to fuse with inter maxillary segment
where is a posterior cleft and what causes it
posterior to incisive foramen
lack of fusion of lateral palatine plates
cleft palate and or uvula
What causes an oblique facial cleft
failure of maxillary process to fuse with lateral nasal prominence
where is an oblique facial cleft
from mouth towards eye resulting in nasolacrimal duct not being incorporated into face
What is the overal cause of craniofacial defects
neural crest defects
What are names of neural crest defects
treacher collins syndrome, DiGeorge Anomaly
