Cranial Fossas Flashcards
What are the three layers of meninges?
Dura Mater
Arachnoid mater
Pia Mater
where are the sinuses in the brain found? Between which layers?
they are found bewteen the two layers of the dura mater - the periosteal layer and the miningeal layer
what are the two layers of the dura mater called?
periosteal layer and the meningeal layer
where do the blood vessels surrounding the brain sit?
they are all in the subarachnoid space
two large sheets of dura project into the cranial cavity dividing compartments - what are they called?
falx cerebri
falx cerebelli
and tentorium cerebelli
the dural sinuses contain what?
venous drainage
what are the various dural sinuses of the brain?
superior sagital sinus, inferior sagital sinus, straight sinus, confluence of sinuses, transverse sinus, sigmoid sinus and cavernous sinus
where do the superior and inferior petrosal sinuses enter the dural sinuses?s
Superior petrosal sinus connects transverse sinus with the cavernous sinus
inferior petrosal sinus connects the cavernous sinus with the sigmoid sinus
what travels through the cavernous sinus?
Cranial nerves 3,4,5a,5b,6 and internal carotid artery
what is in the subarachnoid space?
CSF and blood vessels
what makes cerebrospinal fluid?
choroid plexus
what are the ventricles of the brain? What connects them?
lateral ventricles , 3rd and 4th
lateral connects to 3rd via foramen of monroe
3rd connects to 4th via the cerebral aquaduct
where does CSF pass out of the brain?
through the foramen of magendie and the foramen lushka
What are the four cisterns for CSF?
-interpeduncular
pontine
quadrigeminal
cisternal magna
Describe what might occur in an Extradural bleed?
ex) skull fracture tears the middle meningeal artery - bleeds into extradural space
- usually in temporal/tempero parietal region
occasionally results due to damage of the transverse sinus
Clinical presentation:
- initial loss of consciousness
- lucid interval
- rapid deterioration within 24 hours
Describe a subdural haematoma?
acute and chronic ones
- due to venous bleeds
- chronic version occurs mainly in infancy and old age
- trauma can cause this if acute
predisposing factors = cerebral atrophy (old age), low CSF pressure, alcoholism, coag. disorder
clinical features- dementia, deterioration of conscious level, signs of raised ICP, limb weakness
describe a subarachnoid haemorrhage
bleeding from one of the intracranial vessels in the subarachnoid space -
most often cuased by a cerebral aneurysm
clinical presentation = blow to head headache - loss of consciousness, nausea/vomiting, neck stiffness, seizures, Signs of raised ICP
on CT- show density of blood
