Growth and development of skull Flashcards
What is the name for a baby skull?
Neonate
what allows the moulding of the neonate skull?
- wide sutures
- fontanelles (soft spots)
- thin deformable bones of neurocranium
What parts of the neonate skull show minimal development?
- non-essential parts
- small jaws
- small nose
what is pelvic inlet?
transverse diameter wider than AP diameter
what is pelvic outlet?
AP diameter wider than transverse
what are is the ratio of the skull to the face in the neonate skull and adult skull?
neonate 8:1
adult 2.5 :1
What are the two types of ossification?
- intramembranous- begins to ossify during fatal period, beings at centre of ossification and grows outward
- endochondral- cartilaginous bone formation where bone replaces the cartilage and starts at primary ossification centre
What parts of the skull are formed by intramembranous ossification?
flat bones of the skull e.g. frontal parietal and are easily modified by environmental factors
what parts of the skull are formed by endochondral ossification?
The bones of the base of the skull that support the brain i.e ethmoid , sphenoid
What is hydrocephaly?
when brain grows within cranial cavity and lifts the membrane bones ( frontal) and so applies tension to the sutures between the bones which stimulates bone formation at sutures.
What is spheno-ethmoidal synchondrosis?
cartilaginous joint between the sphenoid and ethmoid bones and closes at age 6
what is spheno-occipital synchondrosis?
cartilaginous joint between sphenoid and occipital bone which becomes active after birth and closes at adolescence
What is meant by diploe?
- outer layer is compact bone
- light cancellous bone
- inner layer is compact bone
How does diploe help protect the brain?
Trauma to outer bone will fracture it but cancellous bone will absorb and spread the trauma to stop it effecting the brain
What happens when there is blows to the maxillary region?
thin walls crumple and le fort fractures
What happens when there is blows to the mandible region?
the dense bone helps absorb force and fractures
during masticatory forces, what parts does the mandible and maxilla play?
mandibule- dense bone , spreads force
maxilla- dissipates force onto neurocranium to prevent fracture
What is the main role of the buttress system?
force dispersal
what happens in the buttress system?
During high masticatory forces, thickened areas of bone transmit forces away from areas of thinner bone (bypassing nasal and orbital cavities)
What occurs from edentulous changes?
after tooth loss, alveolar processes reabsorb
