craniofacial development part 2 Flashcards
what does the cephalocaudal gradient describe?
the increase size from head to feet
what are the 4 types of growth in craniofacial development?
-cranial vault
-cranial base
-naso-maxillary complex
-mandible
what are the 3 embryonic origins known as?
-desmocranium (cranial vault)
-chondocranium (cranial base)
-viscerocranium (facial skeleton)
what are fontanelles?
membrane filled spaces between flat bones
what are fontanelles commonly called?
soft softs
what is the purpose of fontanelles?
-facilitate birth
-allow for growth of brain
what do fontanelles become?
bone by undergoing intramembraneous ossification
what cells become bone when undergoing intramembraneous ossification?
fibrous mesenchyme connective tissue become bone
what are the four frontanelles called?
anterior
posterior
sphenoid
mastoid
name the cranial sutures from ant to posterior
frontal
coronal
saggital
lambdoid
parietal
do sutures have the same purpose as fontanelles?
yes
when sutures undergo ossification where does deposition and resorption occur?
inner resorption
outer deposition
what are premature fusion conditions collectively known as?
craniosynotoses
what is crouzen syndrome?
premature fusion of cranial sutures
what does cousin syndrome cause?
-bossing skull
-proptosis
what is aperts syndrome?
premature fusion of the transverse sutures (coronal and lamboid)
what would indicate alerts syndrome?
high frontal forehead
what is plagiocephaly?
premature fusion of coronal and saggital sutures
what would indicate plagicephaly?
posterior bossing
what does triganocephaly cause?
triangular forehead
where does endochondral ossification occur?
cranial base
what does endochrondreal ossification entail?
cartilage becomes bone
what are the areas of synchondrosis that are replaced by bone in the cranial base?
sphenoid-ethmodial
inter-sphenoid
spheno-occipital
what type of ossification does the nasomaxillary complex undergo?
intramembraneous ossification as there is no cartilage
what are the two stages of nasomaxillary growth?
1- apposition of bone at the sutures that connect maxilla to the cranial base
2-displacement remodelling- where the cranial base pushes the maxilla down and forward from the sutures and resorption of the anterior parts of maxilla/zygomatic bone
what growth does the mandible undergo?
both intramembraenous ossification and endochondral ossification (condyle)
what is the embryonic precursor of the mandible?
meckels cartilage
what is meckels cartilage essentially used as?
a template for the intramembraneous ossification of the mandible
what is the secondary cartilage produced?
condyle
what does the condyle undergo?
endochondral ossification
in what way does the mandible grow?
downwards and forewards
where does bone deposition occur?
posterior of mandible and posterior of coronoid notch and chin
where does bone resorption occur?
anterior of mandible
how is the nasomaxillarfy complex formed and why?
intramembraneous ossification as there is no cartilage
