Cerebral Vasculature and Cerebrovascular disorders

Question 1

why is the brain so very vulnerable if blood supply is impaired?

Answer 1

10-20% of all cardiac output - 20% of all body O2 consumption and 66% of liver glucose 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

Circle of Willis

Answer 3

Question 4

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

Answer 4

middle cerebral artery

Question 5

what artery sits on the pons?

Answer 5

basilar artery

Question 6

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

Answer 6

posterior communicating artery

Question 7

what do the vertebral arteries connect to form?

Answer 7

basilar artery

Question 8

Venous drainage of the brain pathway

Answer 8

Cerebral veins–>dural venous sinuses–>internal jugular vein

Question 9

where is the confluence of sinuses?

Answer 9

at the base of the occipital bone, medially.

Question 10

what does the sigmoid sinus eventually become?

Answer 10

internal jugular vein

Question 11

Meningeal layers

Answer 11

Question 12

Types of haemorrhage based on meningeal association

Answer 12

Question 13

What type of haemorrhage is 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

Two types of stroke

Answer 15

Thrombo-embolic (85%) or haemorrhage (15%)

Question 16

What is a transient ischaemic attack?

Answer 16

rapidly developing focal disturbance of brain function of presumed vascular origin that resolves completely within 24 hours

Question 17

what is an infarction?

Answer 17

Degenerative changes which occur in tissue following occlusion of an artery

Question 18

what is cerebral ischaemia?

Answer 18

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

Question 19

what is a thrombosis?

Answer 19

formation of a blood clot (thrombus)

Question 20

what is an embolism?

Answer 20

plugging of small vessel by material carried from larger vessel e.g. thrombi from the heart or atherosclerotic debris from the internal carotid

Question 21

what is the difference between embolism and thrombosis?

Answer 21

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

Question 22

Complications of stroke

Answer 22

Permanent disability
Obvious neurological deficit

Question 23

what are the risk factors for a stroke?

Answer 23

AGE
hypertension
cardiac disease
smoking
diabetes mellitus

Question 24

what is a perfusion field?

Answer 24

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

Question 25

what is the perfusion field for the middle cerebral artery?

Answer 25

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

Question 26

what is the perfusion field for the anterior cerebral artery?

Answer 26

medial part of cerebral cortex

Question 27

what is the perfusion field for the posterior cerebral artery?

Answer 27

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

Question 28

how does an occlusion of the anterior cerebral artery present?

Answer 28

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

Question 29

how does an occlusion of the middle cerebral artery present?

Answer 29

classic stroke
contralateral hemiplegia (arm) and hemisensory deficits
hemianopia
aphasia if left sided lesion (because Broca’s/ Wernicke’s)

Question 30

how does an occlusion of the posterior cerebral artery present?

Answer 30

visual defects - homonymous hemianopia, visual agnosia

Question 31

path of venous drainage of the brain

Answer 31

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 32

What major risk factor for stroke is evident in this specimen?

Answer 32

The yellow discolouration in the walls of the vessels is a build-up of atheroma, fatty deposits that cause atherosclerosis or“hardening of the arteries”

Question 33

Which cerebral artery has been occluded in this specimen?

Answer 33

The marked area shows
evidence of infarction in the
perfusion field of the right
middle cerebral artery