1. Carotid Circulation Major regions supplied Optic nerves and retina
Cortex and deep white matter
Frontal and parietal lobes
Lateral parts of the temporal and occipital lobes
Corpus callosum - except splenium (posterior)
Most of the basal ganglia (including amygdala)
Internal capsule
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2. ACA Key functional areas supplied Septal area Primary motor cortex
Leg and foot areas
Area controlling urinary bladder
Motor planning areas in medial frontal lobe, anterior to the precentral gyrus
Primary somatosensory cortex for leg and foot
Most of corpus callosum except splenium
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3. MCA-superior branches
Key functional areas supplied
Primary motor cortex - face / arm areas
Pyramidal tract axons from all of the primary
motor cortex
Primary somatosensory cortex - face / arm areas
Frontal eye fields
Frontal/parietal - language-dominant hemisphere
Broca’s and other areas for language expression
Frontal/parietal - nondominant hemisphere
areas for 3-D visuospatial concepts of self and world
areas for expressing emotions
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4. MCA-inferior branches
Key functional areas supplied
Visual radiations
Fibers representing information from contralateral
superior quadrants
Temporal/parietal- language-dominant hemisphere
Wernicke’s and other areas for language comprehension
Posterior parietal - nondominant hemisphere
areas for 3-D visuospatial perceptions of self and world
areas for interpreting emotions
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5. Vertebral-Basilar Circulation
Major regions supplied
Upper cervical spinal cord
Brainstem and cerebellum
Most of thalamus and hypothalamus
Cortex and deep white matter
Posterior medial parietal lobes
Medial and infrior temporal and occipital lobes
Splenium of corpus callosum
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6. PCA Key functional areas supplied By long penetrating branches
Thalamus, subthalamic nucleus, hypothalamus
Midbrain
By cortical branches - parietal and occipital lobes
Visual radiations and primary visual cortex
Splenium of corpus callosum
By cortical branches - medial temporal lobe
Hippocampal formation and posterior fornix
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7. Common Anastomoses Collateral circulation may prevent ischemia
External-internal carotid via ophthalmic branches
Circle of Willis
Muscular branches of cervical arteries-vertebral
or external carotid arteries
Short cortical branches of ACA, MCA, PCA
Branches of the major cerebellar arteries
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8. ACA-MCA Border Zone Key functional areas that may be present
Hip or shoulder (occasionally arm) regions of primary motor or somatosensory cortex
Regions involved in aspects of language production (in the dominant hemisphere)
Frontal Eye Fields
Motor planning areas in frontal lobe
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9. ACA/MCA-PCA Border Zone
Key functional areas that may be present
Visual radiations
Foveal representation in the primary visual cortex
Inferior temporal lobe cortex for visual recognition
Regions for language comprehension and word finding (possibly reading) in dominant hemisphere
Regions important for visuospatial perceptions in parietal lobe of nondominant hemisphere
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10. What is a TIA?
A Transient Ischemic Attack (TIA) is a brief episode in which neurologic deficits suddenly occur, but then disappear completely
Most TIAs last a few minutes to an hour.
No neurologic deficits remain once a TIA
has ended, because little or no brain tissue is
permanently damaged.
A TIA is an indicator that the stage is set
for an ischemic stroke.
Treatment of patients with TIAs can significantly
reduce their risk of having a stroke.
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11. TIAs: Carotid Territory
Transient monocular blindness
TMB (also known as amaurosis fugax) occurs when the retina becomes temporarily ischemic.
Patients commonly describe a gray or black fog
or a mist clouding vision in all or part of one eye.
Attacks are typically brief (1-5 minutes), and
afterwards vision is fully restored.
TMB often signals the presence of severe
ipsilateral carotid artery disease in older adults.
TMB can also be caused by migraine.

12. TMB: What’s Mechanism? Two Ideas:
1. Thrombus from ulcerated atherosclerotic plaque at the origin of the internal carotid artery enters ophthalmic artery and plugs retinal vessel.
A small embolic particle can produce retinal ischemia
or block the central retinal artery.
If the embolus (often a platelet-fibrin aggregate) falls
apart, blood flow is restored and and vision returns.
2. Low perfusion in the internal carotid artery, putting distal structures like the retina at risk.
This mechanism implies presence of severe carotid
stenosis that significantly impairs blood flow.

13. TIAs: Carotid Territory
Transient hemispheric attacks
Problems typically produced
One-sided limb weakness, clumsiness or paralysis
One-sided numbness, paresthesia, or sensory loss
Difficulty with language production or
comprehension
Inability to articulate words clearly, often
described as ‘I slurred my words’ (dysarthria)
Partial or complete homonymous visual field
defects (patients seldom describe these)

14. atherosclerotic plaque and thrombus
Carotid Bifurcation
atherosclerotic plaque and thrombus
Thrombus on
plaque surface
Plaque
Thrombus on
plaque surface
Plaque reduces the
diameter of artery

15. TIAs: Vertebral-Basilar
Various combinations may be present
Problems typically produced
Vertigo or dizziness
Unilateral or bilateral weakness or clumsiness
Unilateral or bilateral numbness or sensory loss
Limb ataxia or coarse tremor, staggering gait
Dysarthria
Visual field defect, blindness, or diplopia
Nystagmus (‘it jumps around when I look at it’)

16. Patients may ignore TIAs!
Because the episode of impaired function is brief, patients may not tell you about it unless you ask.
Seniors with somewhat impaired memory may simply not recall such brief events.
TIAs in carotid territory predict severe atherosclerosis
in the proximal internal carotid artery.
Tests can determine actual blood flow in the carotid.
The odds of stroke in the next 1-2 weeks are great!
If severe narrowing is present, surgical and medical
treatments can help to reduce stroke risk.