A11 - Skull Development Flashcards
What features of the neonate skull allow moulding?
moulding- part of the skull to move over each other
wide sutures
fontanelles
thin deformable bones
Describe the compromise of a neonate skull
big skull for a big brain but to too big impairing delivery
What does a neonate skull contain which a developed skull does not?
frontal suture
fontanelles - anterior antero/posterolateral
eminaces - fontal and parietal centres of ossification
What are the key features of the adult skull
lightness - oral, nasal and cranial cavities, paranasal, frontal sinuses, hollow bone, ethmoid air cells
strength - protect the brain, sphere shaped to maximise volume and strength but minimum weight and SA,
open airways - nasal cavity is always open
warm and humid - conchae in nose humidify and warm air for better gas exchange
muscle attachment and support - using muscles contraction increases size of skull
attractiveness - features get us to the point of reproduction
What are the importance of sutures ?
the join bones and stop trauma from spreading
Explain the function of the crumple zone in providing protection amd strength
bones are thinner and so fracture with force but eliminate trauma spreading to neurocavity
What does skull growth rate depend on?
ratio of skull to face - adult 2:5:1, neonate 8:1
brain growth
sex hormones - male skulls are bigger than females
jaw growth - driven by teeth development
muscle attachment - causes tension in bone causing it to grow
joint movement - allow face to move forward in relation to skull
What is the type of ossification of membranous bone formation at centres of ossification?
intramembranous
What is cartilaginous ossification where cartilage is placed and then replaces with bone?
Endochondral
What are immovable joints between bones bound by a layer of cartilage which allow the base to move in relation to the skull?
synchondroses
Where are the two synchondroses situated in skull?
sphenio-ethmoidal - between sphenoid and ethmoid
sphenio-occipital - between sphenoid and occipital
Explain the dipole of bone.
think layer of light cancellous bone sandwiched between two layers of thin compact bone
How does the dipole confer lightness and protection to the skull?
trauma hits the outer compact bone but the inner cancellous bone prevents the spread to the inner cranium
How does the buttress system provide protection?
- force dispersion
- high masticatory forces are transmitted away from thin areas of bone to prevent them crumpling when chewing
What effect does edentulous changes have on the skull?
tooth loss can cause the alveolar process to resolve which is clinically important as the nerve can become closer to the surface
