H&N 2.1 osteology Flashcards
How many bones make up the skull?
22
How can the skull be divided up?
Neurocranium (which can be further split into calvaria and base of skull) and viscerocranium
How many bones make up the viscerocranium?
14
Name the bones that make up the viscerocranium.
2x lacrimal 2x nasal 2x maxilla 2x pallatine 2x zygomatic bone 2x inferior nasal conchae vomer mandible
How many bones make up the neurocranium?
8
Name the bones that make up the neurocranium.
2x parietal 2x temporal ethmoid sphenoid frontal occipital
What 2 types of joints are found within the skull?
- immobile joints (between bones, sutures, strong fibrous tissue)
- mobile- hinge joint of TMJ.
What sutures do we have within the skull?
coronal suture
sagital suture
lamboid suture
squamous suture
What do Bregma, lambda and the pterion signify?
They are where 2 or more sutures join.
What are fontanelles?
In the developing child, the skull doesnt form fully before birth, there are holes between bones before theyve fused.
‘Membranous area of unfused skull.
might be known as soft spots.
What are 2 functions of fontanelles?
- skull is more flexible which aids birth
- allows the brain to grow
What’s important to look out for with the fontanelles? what might this signify?
If they’re sunken- sign of dehydration
If they’re bulging- signs of raised ICP, poor prognosis
What does the anterior fontanelle form?
Bregma
What does the posterior fontanelle form?
Lamba
How many cervical vertabrae do we have?
7
How many cervical nerves do we have?
8
Give some distinguishing features of C1- Atlas.
- has no cell body
- doesnt have a bifid spinous process (doesnt really have one)
- anteriorly has a facet for articulating with the dens.
- lateral masses either side to attach transverse ligaments of the atlas.
Give some distinguishing features of C2- Axis
Has the dens which will articulate with the anterior facet on the atlas, and allows for rotation of the head.
If you suspect a skull fracture, what imaging method would you use?
CT scan.
What bones join to make the pterion?
Parietal, temporal, sphenoid and frontal
What is the significance of the pterion?
It is the weakest part of the skull, and running directly below it is the middle meningeal artery, so damage to the pterion can damage the middle meningeal artery.
What is it called when damage to the pterion damages the middle meningeal artery and blood builds up?
extradural haemorrhage
Between what layers do extradural heamorrhages occur?
The periosteum and the dura mater (outermost dural layer)
Why is an extradural haemorrhage dangerous?
As the blood builds up, it pushed the brain and surrounding structures away, the midline gets shifted. You get a raised ICP, which can lead to respiratory failure.
What are some typical signs of a basilar skull fracture?
CSF rhinorrhoea battles sign (bruising of mastoid) raccoons sign (bilateral bruising around eyes)
What complications can arise following a basilar skull fracture?
- meningeal tears which can lead to reduced CSF volume (rhinorrhoea), and can be a route for infection, leading to meningitis
- Cranial nerve palsies, due to damage of one or more of hte cranial nerves
- if neurosurgical intervention is required, this itself carries high risk of lots of complications.
What can osteoarthritis of the spine lead to?
cervical spondylosis
What are some features of cervical spondylosis?
bony spurs disc space narrowing facet joint hypertrophy disc herniation sclerosis of the end plates
What are the 2 main complications of cervical spnodylosis?
cervical spondylotic radiculopathy
cervical spondylotic myelopathy
What happens in cervical spondylotic radiculopathy?
There is spinal nerve impingement, usually you’ll get arm pain, and mild weakness and sensory loss
what happens in cervical spondylotic myelopathy?
Compression of the spinal cord, this leads to loss of function, and general loss of fine motor skills in the upper limb.
