Blood Supplies and Strokes

Question 1

Describe the 5 major branches of the anterior portion of the circle of Willis. (5)

Answer 1

Anterior cerebral 
Anterior communicating
Middle cerebral 
ICA
Ophthalmic

Question 2

Describe the 8 major branches of the posterior portion of the circle of Willis. (8)

Answer 2

Posterior communicating
Posterior cerebral 
Superior cerebellar
Basilar 
Pontine
Anterior inferior cerebellar 
Vertebral 
Posterior inferior cerebellar

Question 3

Describe the blood supply to the brainstem.

Answer 3

Superior cerebellar, anterior inferior cerebellar, and posterior inferior cerebellar all supply the brainstem on their way to supply the cerebellum.

Question 4

Describe the two blood imputs into the circle of Willis, and what they supply blood to. (5)

Answer 4

The anterior circulation is fed by the the internal carotid artery and supplied most of the cerebral hemispheres.
The posterior circulation is fed by the vertebral arteries and supplies the brainstem, cerebellum, and portions of the temporal and occipital lobes.

Question 5

Describe the two main cortical branches of the middle cerebral artery. (5)

Answer 5

Two main branches that emerge from the lateral fissure to supply the lateral aspect of the cerebrum (lateral frontal and parietal, superior temporal). The superior branch supplies anterior to the central sulcus, the inferior branch posterior to the central sulcus and they share the primary sensory cortex.

Question 6

Describe why the middle cerebral artery can be said to supply the macula even though it is supplied by the retinal artery (branch of opthalmis) which doesn’t come off the MCA. (2)

Answer 6

The MCA is a continuation of the ICA, and the ophthalmic is a branch of the ICA.

Question 7

Describe the deep branches of the middle cerebral artery and give them their official name. (4)

Answer 7

Lenticulostriate arteries supply deep grey matter including the lentiform nucleus, the basal ganglia, and the internal capsule.

Question 8

Describe the area of cortex that the anterior cerebral artery supplies. (4)

Answer 8

Vessels loop over the corpus callosum, supplying it and the adjacent cortex. The cortical branches supply the medial aspect of the frontal and parietal lobes (not the occipital lobes).

Question 9

Describe the posterior cerebral artery. (1)

Answer 9

A terminal bifurcation of the basilar artery.

Question 10

Describe the root of the anterior cerebral artery. (2)

Answer 10

Branches of the ICA that anastomose via the anterior communicating artery.

Question 11

Describe the structures that are supplied by the posterior cerebral artery. (4)

Answer 11

Supplies the occipital lobe, inferior temporal lobe, thalamus, midbrain.

Question 12

Describe the main sign of a posterior cerebral artery stroke. (3)

Answer 12

Homonymous heminanopia with macular sparing.

Question 13

Describe the formation of the basilar artery. (1)

Answer 13

Confluence of the vertebral arteries.

Question 14

Describe the major branches of the basilar artery. (4)

Answer 14

Posterior cerebral
Superior cerebellar
Pontine
Anterior inferior cerebellar

Question 15

Describe the blood supply to the brainstem. (6)

Answer 15

Midbrain - superior cerebellar and posterior cerebral
Pons - pontine and anterior inferior cerebellar branch.
Medulla - basilar and posterior inferior cerebellar branch.

Question 16

Describe the two branches of the vertebral arteries. (4)

Answer 16

Anterior spinal arteries converge on the midline to supply the anterior 2/3 of the spinal cord.
Posterior inferior cerebellar artery supplies the posterior inferior aspect of the cerebellum.

Question 17

Define the term stroke. (2)

Answer 17

A cerebrovascular accident

A serious, life-threatening medical condition that occurs when the blood supply to part of the brain is cut off

Question 18

Describe the differences between a stroke and a mini-stroke. (2)

Answer 18

A mini-stroke, or a transient ischaemic attack, involves stroke symptoms that resolve in 24 hours.

Question 19

Describe the three main types of stroke, the occurrence of these type, and give some examples of them. (11)

Answer 19

Ischaemic (85%) - thromboembolic
Haemorrhagic (10%) - intercerebral, subarachnoid.
Other (5%) - dissection of carotid artery, venous sinus thrombosis, hypoxia brain injury (esp post cardiac arrest).

Question 20

Describe the three types of findings that you might see on a head CT following a stroke. (6)

Answer 20

In an acute ischaemic stroke, there will be no CT findings.
In a haemorrhagic stroke, there will be blood seen on a CT.
In an acute ischaemic stroke presenting after 4 hours, the ischaemia will be visible on a CT.

Question 21

Describe the symptoms of an anterior cerebral artery infarct. (11)

Answer 21

Contralalteral motor weakness of the leg and shoulder.
Contralateral sensory weakness of the leg and shoulder.
Urinary incontinence - paracentral lobules lost.
Apraxia - most common in left sided stroke
Dysarthria
Corpus callosum involvement - split brain syndrome.

Question 22

Describe the symptoms of a middle cerebral artery infarct. (16)

Answer 22

Contralateral full hemiparesis - internal capsule involvement.
Contralateral sensory loss of arms and face.
Contralateral homonymous hemianopia - lost the macula and the opposite side (not the side of the infarct) of the visual field.
Aphasia - only with dominant hemisphere infarct - Broca’s (superior branch) and Wernicke’s (inferior branch).
Hemispatial neglect - non-dominant hemisphere only - can’t comprehend half of the world.

Question 23

Describe the symptoms of a lenticulstriate artery infarct. (3)

Answer 23

Infarction of the internal capsule and basal ganglia that doesn’t affect the cortex - contralateral full hemiparesis.

Question 24

Describe the symptoms of a posterior cerebral artery infarct. (4)

Answer 24

Contralateral homonymous hemianopia with macula sparing.

Contralateral sensory loss due to thalamus involvement.

Question 25

Describe the symptoms of a cerebellar infarct. (6)

Answer 25

Often non-specific symptoms - N+V, headache, dizziness, sudden onset vertigo.
Ipsilateral cerebellar signs - DANISH
Ipsilateral brainstem signs
Contralateral sensory deficit.

Question 26

Describe the symptoms of a brainstem infarct. (4)

Answer 26

Contralateral ascending and descending tract damage - sensory and motor
Ipsilateral cranial Nerve signs - brainstem nuclei are ipsilateral.

Question 27

Describe the symptoms of a basilar artery infarct. (7)

Answer 27

Can cause sudden death.
If distal in the artery - “top of basilar Syndrome” - no motor dysfunction, behavioural abnormalities, visual defects.
If proximal in the artery - “locked in symdrome” - preserved occulomotor function only.

Question 28

Describe the Bramford or Oxford classification of strokes. (4)

Answer 28

Total anterior circulation strokes (TACS)
Partial anterior circulation strokes (PACS)
Posterior circulation strokes (POCS)
Lacunar strokes (LACS)

Question 29

Describe the diagnostic criteria for a TACS and list which artery it could be. (5)

Answer 29

All three of:
Unilateral weakness of face, arms and legs
Homonymous hemianopia
Higher cerebral dysfunction - dysphagia, visuospacial disorder.
MCA.

Question 30

Describe the diagnostic criteria for a PACS and list which artery it could be. (6)

Answer 30

2 of:
Unilateral weakness of face, arms and legs
Homonymous hemianopia
Higher cerebral dysfunction - dysphagia, visuospacial disorder.
MCA commonly, or ACA.

Question 31

Describe the diagnostic criteria for a POCS and list which artery it could be. (9)

Answer 31

One of the following:
Cranial nerve policy and contralateral motor / sensory deficit.
Bilateral motor / sensory deficit.
Conjugate eye movement disorder.
Cerebellar dysfunction
Homonymous hemianopia with macular sparing.
PCA / basilar / vertebral

Question 32

Describe the diagnostic criteria for a LACS and list which artery it could be. (5)

Answer 32

One of the following:
Pure sensory deficit
Pure motor deficit 
Mixed sensory and motor deficit 
Ataxic hemiparesis. 
Lenticulostriate.