Cerebral Vasculature and Cerebrovascular disorders

Question 1

why is the brain vulnerable if blood supply is impaired?

Answer 1

10-20% of all cardiac output - 20% of all body O2 consumption despite being only 2% of body weight

Question 2

what are the main blood supplies for the brain?

Answer 2

vertebral arteries

internal carotid arteries (common carotid)

Question 3

what is the main cerebral branch of the internal carotid artery?

Answer 3

middle cerebral artery

Question 4

what artery sits on the pons?

Answer 4

basilar artery

Question 5

what artery connects the posterior cerebral artery and the middle cerebral artery?

Answer 5

posterior communicating artery

Question 6

what artery connects the anterior cerebral artery and middle cerebral artery?

Answer 6

anterior communicating artery?

Question 7

what do the vertebral arteries connect to form?

Answer 7

basilar artery

Question 8

where is the confluence of sinuses?

Answer 8

at the base of the occipital bone, medially.

Question 9

what does the sigmoid sinus eventually become?

Answer 9

internal jugular vein

Question 10

which type of cranial haemorrhage is mostly associated with immediate clinical effects?

Answer 10

extradural

Question 11

what type of cranial haemorrhage is most associated with delayed clinical effects?

Answer 11

subdural

Question 12

what type of cranial haemorrhage is most associated with ruptured aneurysms?

Answer 12

subarachnoid

Question 13

what type of cranial haemorrhage is mostly associated with pterion trauma?

Answer 13

extradural

Question 14

what is a cerebrovascular accident?

Answer 14

rapidly developing focal disturbance of brain function of presumed vascular origin and of >24hr duration

Question 15

what is the difference between a cardiovascular accident and a transient ischaemic attack?

Answer 15

TIAs have the same definition, yet always resolve within 24hrs with no lasting deficits. they are often a warning of subsequent strokes

Question 16

what is an infarction?

Answer 16

degenerative changes after losing blood supply/occlusion of an artery

Question 17

what is cerebral ischaemia?

Answer 17

lack of sufficient blood supply to nervous tissue resulting in permanent damage if blood flow is not restored quickly

Question 18

what is a thrombosis?

Answer 18

formation of a blood clot

Question 19

what is an embolism?

Answer 19

plugging of small vessel by material carried from larger vessels e.g thrombosis, debris, air, fat

Question 20

what is the difference between embolism and thrombosis?

Answer 20

a thrombosis is a type of embolism (a blood clot that may travel and cause embolism)

Question 21

what are the risk factors for a stroke?

Answer 21

AGE
hypertension
cardiac disease
smoking
diabetes mellitus

Question 22

what is a perfusion field?

Answer 22

region of the brain a specific vessel is responsible for providing o2 to

Question 23

what is the perfusion field for the middle cerebral artery?

Answer 23

most of the lateral surface of the cerebral cortex and subcortical deep structures

Question 24

what is the perfusion field for the anterior cerebral artery?

Answer 24

medial part of cerebral cortex

Question 25

what is the perfusion field for the posterior cerebral artery?

Answer 25

occipital lobe laterally extending to below the thalamus medially (inferior temporal)

Question 26

how does an occlusion of the anterior cerebral artery present?

Answer 26

paralysis of contralateral LEG, arm, face disturbance of intellect, judgement and executive function loss of appropriate social behaviour

Question 27

how does an occlusion of the middle cerebral artery present?

Answer 27

classic stroke contralateral hemiplegia (arm) and hemisensory deficits hemianopia aphasia if left sided lesion

Question 28

how does an occlusion of the posterior cerebral artery present?

Answer 28

visual defects - homonymous hemianopia, visual agnosia, prosopagnosia

Question 29

path of venous drainage of the brain

Answer 29

inferior/superior sagittal sinus --> confluence of sinuses --> Great cerebral vein --> straight sinus --> confluence of sinuses --> Transverse sinus --> sigmoid sinus --> jugular foramen--> internal jugular vein

Question 30

what are the venous sinuses of the brain

Answer 30

``` inferior/superior sagittal sinus straight sinus confluence of sinuses transverse sinus sigmoid sinus ```

Question 31

how does venous blood drain in the cerebral cortex itself

Answer 31

though dura mater forming dural venous sinuses