Cerebral Vasculature and Cerebrovascular disorders Flashcards
why is the brain vulnerable if blood supply is impaired?
10-20% of all cardiac output - 20% of all body O2 consumption despite being only 2% of body weight
what are the main blood supplies for the brain?
vertebral arteries
internal carotid arteries (common carotid)
what is the main cerebral branch of the internal carotid artery?
middle cerebral artery
what artery sits on the pons?
basilar artery
what artery connects the posterior cerebral artery and the middle cerebral artery?
posterior communicating artery
what artery connects the anterior cerebral artery and middle cerebral artery?
anterior communicating artery?
what do the vertebral arteries connect to form?
basilar artery
where is the confluence of sinuses?
at the base of the occipital bone, medially.
what does the sigmoid sinus eventually become?
internal jugular vein
which type of cranial haemorrhage is mostly associated with immediate clinical effects?
extradural
what type of cranial haemorrhage is most associated with delayed clinical effects?
subdural
what type of cranial haemorrhage is most associated with ruptured aneurysms?
subarachnoid
what type of cranial haemorrhage is mostly associated with pterion trauma?
extradural
what is a cerebrovascular accident?
rapidly developing focal disturbance of brain function of presumed vascular origin and of >24hr duration
what is the difference between a cardiovascular accident and a transient ischaemic attack?
TIAs have the same definition, yet always resolve within 24hrs with no lasting deficits. they are often a warning of subsequent strokes
what is an infarction?
degenerative changes after losing blood supply/occlusion of an artery
what is cerebral ischaemia?
lack of sufficient blood supply to nervous tissue resulting in permanent damage if blood flow is not restored quickly
what is a thrombosis?
formation of a blood clot
what is an embolism?
plugging of small vessel by material carried from larger vessels e.g thrombosis, debris, air, fat
what is the difference between embolism and thrombosis?
a thrombosis is a type of embolism (a blood clot that may travel and cause embolism)
what are the risk factors for a stroke?
AGE hypertension cardiac disease smoking diabetes mellitus
what is a perfusion field?
region of the brain a specific vessel is responsible for providing o2 to
what is the perfusion field for the middle cerebral artery?
most of the lateral surface of the cerebral cortex and subcortical deep structures
what is the perfusion field for the anterior cerebral artery?
medial part of cerebral cortex
what is the perfusion field for the posterior cerebral artery?
occipital lobe laterally extending to below the thalamus medially (inferior temporal)
how does an occlusion of the anterior cerebral artery present?
paralysis of contralateral LEG, arm, face
disturbance of intellect, judgement and executive function
loss of appropriate social behaviour
how does an occlusion of the middle cerebral artery present?
classic stroke
contralateral hemiplegia (arm) and hemisensory deficits
hemianopia
aphasia if left sided lesion
how does an occlusion of the posterior cerebral artery present?
visual defects - homonymous hemianopia, visual agnosia, prosopagnosia
path of venous drainage of the brain
inferior/superior sagittal sinus –> confluence of sinuses –> Great cerebral vein –> straight sinus –> confluence of sinuses –> Transverse sinus –> sigmoid sinus –> jugular foramen–> internal jugular vein
what are the venous sinuses of the brain
inferior/superior sagittal sinus straight sinus confluence of sinuses transverse sinus sigmoid sinus
how does venous blood drain in the cerebral cortex itself
though dura mater forming dural venous sinuses
