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In this chapter, we will review cerebrovascular anatomy, different types of strokes, and how they present with various signs and symptoms and review their treatment. CT and MRI images are presented to provide examples that may also be seen on the wards and on the shelf exam.
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ARTERIAL BLOOD SUPPLY TO THE BRAIN
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The blood supply to the brain, like every other organ, has its roots in the aorta. Branches give rise to the anterior and posterior circulations (Fig. 4-1).
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Anterior circulation derives blood from the bilateral internal carotid arteries and supplies blood to most of the cerebral hemispheres, including the frontal lobes, parietal lobes, lateral temporal lobes, and anterior part of deep cerebral hemispheres (Figs. 4-2A and 4-2B).
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Begins with the internal carotid arteries (external carotid arteries are extracranial) which migrate up the neck, through the skull and end in the circle of Willis (Fig. 4-3).
The anterior cerebral arteries (ACA) supply the most medial, frontal, and rostral parts of the cortex.
The middle cerebral arteries (MCA) supply the lateral cortices, including the frontal, parietal, and superior temporal lobes.
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KEY FACT
ACA strokes often result in weakness of the contralateral leg.
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KEY FACT
Four arteries bring blood to the brain, two common carotid arteries and 2 vertebral arteries.
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KEY FACT
MCA strokes often are some of the most debilitating as they affect large areas of cortex.
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