Development of the Skull Flashcards
why is an understanding of facial growth needed
malocclusion
abnormal growth patterns
treatment plans
treatment stability
what are some primary cartilages
meckels cart
reichert’s cart
nasal capsule
what is the function of primary cart
primitive support to set out path for facial bone dev and nerve dev
what si the structure of primary carts
hyaline cart
interstitial growth
what si the fate of primary carts
ossify
disappear
what are the two parts for the skull
neurocranium - brain case
viscerocranium - facial skeleton
what are the parts of the neurocranum
dermatocranium - cranial vault
chondrocranium - cranial base
what are the parts of the viscerocranium
special sensory
masticatory
what does the craianl base largely form form
series of cart
what are the primary carts assc with base of skull
trabeculum - nasal capsule hypophyseal cart otic capsule parachordal carts occipital somites occipital cart orbitosphenoid alisphenoid
what are the bones of the cranial base
sphenoid occipialt temporal d- petrous ethmoid frontal
what is the ossification takes place at cranial base
endochondral ossification
where does dermal/membranous bones form
frontal
parietal
squamous temporal
occipital
what bones ossify by intramembranous ossifiction
ectomesenchyme - ant to coronal suture
mesenchyme - post to coronal suture
when does bone formation start
8 weeks for cranial vast
what is it called where bones meet
sutures
what are the common ways of skull growth
sutures
synchondroses
remodelling
secondary cartilages
what are the two growth pathways asscwith cranium
neural - age 10 full
somatic - growth spurts
what is sutural growth
growth due to expansion of underlying structures
what re the layers at a suture
osteoblasts
cambial
capsular
middle layer
what are the fontanelles
ant
anterolateral
posterolateral
posterior
when do the fontanelles close
ant - 6-18 months
anterolat- 6 months
postlat - 6-18moths
post - 1-3months
what is a synchondrosis
immovable cartilage joint
active growths site
what growth occurs at synchondrosis
intersistial growth
when does the spehno-ethmoidal synchondrosis fuse
around birth
when’d does he sphene occipital synchorndoisi fuse
12 female
14 male
main site of elongation of cranial base
what does achondroplasia do to skull formaiton
concave face as middle 1/3rd not as well formed
effects synchondroses growth
how are bone surfaces remodelled
surface depo - osteobalsst
surface resorption- osteoclast
when does the max air sinus form
10 weeks
how does the max air sinus form
primary pneumatisation - sir fill pouch in lat wall nasal cav
secondary pneumatisation - expansion by resorption of lat and inf walls
if a upper post tooth removed how does this affect the sinus
sinus enlarges
alveolar height reduces - thin bone
what are secondary cartilages made of
fibrocartilage
how do secondary cartilages grow
appositional growth
what is appositional growth
surface depo of new coat
calcification of sub-surface cart
resorption of calcified cart
replace of calcified cart with bone
what are some secondary carts
symphyseal
coronoid
condylar
when does symphyseal cart appears and disappear
16 weeks appear
disappear 1st year after brith
when does coronoid cart appear nd disappear
appear 14-16 weeks
dis before birth
when does condylar art appear and sipper
appear - 10-12 weeks
dis - 20 years of age
what are some factors controlling growth patterns
hormonal
intrinsic
extrinsic
what are hormonal influence on growth patterns
growth spurts
what re intrinsic factors affecting growth patterns
within bone or cart - genetic
what are the exrisic factors affecting growth patterns
neural - brain growth special snes e- eye growth muscle activity air sinuses nasal septum growth soft tissue - cheek teeth
