Osteology

Question 1

what is the neurocranium

Answer 1

part of the skull which encases and protects the brain

Question 2

what is the viscerocranium

Answer 2

part of the skull which makes up the jaw and facial skeleton

Question 3

what are the 3 depression in the neurocranium

Answer 3

anterior, middle and inferior cranial fossae

Question 4

what are the layers of bone of the calvaria

Answer 4

trilaminar:

• outer table (compact bone)
• diploeic cavity (spongy bone)
• inner table (compact bone)

Question 5

what is the calvaria

Answer 5

skull cap

Question 6

what are sutures

Answer 6

points are which the skull bones fuse together

Question 7

why are sutures serrated

Answer 7

to prevent slippage

Question 8

what are fontanelles

Answer 8

membranous areas of infant skull which are yet to ossify

Question 9

when do the anterior fontanelles ossify

Answer 9

at 18months-2years

Question 10

when do the posterior fontanelles ossify

Answer 10

at 1-3months

Question 11

what is craniosyntosis

Answer 11

early fusion of the fontalles which impedes brain development and changes the shape of the skull

Question 12

what is the purpose of fontanelles

Answer 12

to allow for skull size and shape to change

Question 13

by which method do the bones on top of the skull develop

Answer 13

intramembranous ossification

Question 14

by which method do the bones of the floor of the skull develop

Answer 14

endochondrial ossification

Question 15

what is a cephalohaematoma

Answer 15

a bleed between the periosteum and the bone

Question 16

true or false: there are inter cranial pressure changes with a cephalohaematoma

Answer 16

false - the blood can’t pass over suture lines as the periosteum is tightly adhered here so only covers that area of bone

Question 17

what are the 2 main fractures of the skull

Answer 17

linear and depressed

Question 18

what is a linear fracture

Answer 18

a fracture all the way through the bone with no bone displacement

Question 19

what is a depressed fracture

Answer 19

where there is displacement of the bone towards the brain

Question 20

what is a basilar skull fracture

Answer 20

fractures involving the cranial base

Question 21

what are the signs associated with a basilar skull fracture

Answer 21

racoon eyes, bruising at the mastoid process, CSF through nose and ears

Question 22

what is the pterion

Answer 22

the thinest part of the skull

Question 23

what blood vessel is found behind the pterion

Answer 23

anterior branch of the middle meningeal artery

Question 24

if there is a fracture at the pterion what type of haematoma would result

Answer 24

an extra dural haematoma - as the vessel is in the dura so blood would collect between the dura and bone