11 - Cranial nerves and blood supply to the brain Flashcards
How does the subclavian artery enter the cranium?
- vertebral branch enters the cranium via the transverse foramina and the foramen magnum
- joins the basilar artery to provide the posterior of the brain
Describe what the ICA supplies in the cranium.
- iCA provides middle and anterior cerebral arteries for anterior supply of brain
- enters cranium via the carotid canal
Where does the ECA supply in the cranium?
Provides meninges via middle meningeal artery (maxillary branch)
What are the intracranial branches of the ICA?
- middle cerebral artery
- anterior cerebral artery
- ophthalmic artery
What are the intracranial branches of the ECA?
- maxillary artery
- middle meningeal artery
- ascending pharyngeal artery
- occipital
What are the intracranial branches vertebral artery?
- basilar artery
- posterior cerebral artery
What is the circle of willis?
- anterior to where the basilar artery crosses the pons and the vertebral artery crosses the medulla
- where the cerebral arteries branch
Where does the anterior cerebral artery supply?
Medial side of frontal lobe
Where does the middle cerebral artery supply?
- lateral side of the frontal lobe
- lateral side of the temporal lobe
Where does the posterior cerebral artery supply?
Lateral and medial side of the occipital lobe
How does stroke affect the anterior cerebral artery?
- contralateral hemiparesis and hemisensory loss (mainly leg and foot)
- unable to identify objects
- personality change
How does stroke affect the middle cerebral artery?
- contralateral hemiparesis and hemisensory loss (mainly face and arm)
- aphasia (LHS)
- contralateral homonymous hemianopia
- anosognosia (lack of insight)
How does stroke affect the posterior cerebral artery?
- contralateral homonymous hemianopia
- visual agnosia
- memory impairment
Describe the dural venous sinuses.
- spaces between periosteal and meningeal layers of dura
- endothelium lined
- venous drainages of brain and CSF resorption via arachnoid granulation
What are the dural septa?
- falx cerebri
- falx cerebelli
- diaphragma sellae
- tentorium cerebelli
Describe the confluence of sinuses.
- found at the posterior of the cranium
- where the straight sinus, superior sagittal and transverse sinuses meet
What are the main venous sinuses in the cranium?
- sigmoid
- L/R transverse
- straight
- superior sagittal
- cavernous
- intercavernous
- petrosal
Describe the cavernous sinus.
- one sinus made up of lots of small vessels
- blood flows very slowly here
- venous drainage of the face and mouth
What is cavernous sinus thrombosis?
- blood clot in the cavernous sinus
- can be caused by infection within the danger triangle
What causes an extradural haematoma?
- fractures or trauma
- loss of consciousness takes a few days
What causes a subdural haematoma?
- older age (falls, not fractures)
- venous bleeds are slow and take weeks to present
What causes subarachnoid haemorrhage?
- associated with aneurysm
- affects any age group
- loss of consciousness very quick
