Stroke continues to be a leading cause of morbidity and mortality.
In the U.S., approximately 795,000 persons experience strokes yearly;
of these events, 77% are primary strokes, whereas 23% represent
recurrent strokes.1 In addition to the human costs,
the financial implications of stroke are massive—strokes
are expected to account for an estimated $73.3 billion
total expenditures in the U.S. in 2010.1 Despite
these grim statistics, from 1996 to 2006 the stroke death rate has
fallen 32.7%,1 and with the growing use
of thrombolysis, stroke units, and other new therapies, there is
new hope for patients with acute stroke who present to the ED.
Stroke may be generally defined as any disease
process that interrupts blood flow to the brain. Injury is related
to the loss of oxygen and glucose substrates necessary for high-energy
phosphate production and the presence of mediators of secondary
cellular injury. Subsequent factors, such as edema and mass effect,
may exacerbate the initial insult.
An understanding of the diagnosis and treatment of stroke must
begin with a working knowledge of the relevant vascular supply and
neuroanatomy of the brain.
The arterial supply to the brain is illustrated in Figures 161-1 and 161-2.
Diagram of a cerebral hemisphere, lateral aspect, showing
the branches and distribution of the middle cerebral artery and
the principal regions of cerebral localization. Note the bifurcation
of the middle cerebral artery into a superior and inferior division.
a. = artery; ant. = anterior; inf. = inferior;
post. = posterior; sup. = superior. (Modified
with permission from Fauci AS, Braunwald E, Kasper DL, et al: Harrison’s
Principles of Internal Medicine, 17th ed.
New York, McGraw-Hill Professional, 2008.)
Diagram of a cerebral hemisphere, medial aspect, showing
the branches and distribution of the anterior cerebral artery, posterior
cerebral artery, and the principal regions of cerebral localization.
a. = artery; ant. = anterior; post. = posterior.
(Reproduced with permission from Fauci AS, Braunwald E, Kasper DL,
et al: Harrison’s Principles of Internal Medicine, 17th
ed. New York, McGraw-Hill Professional, 2008.)
The vascular supply is divided into anterior and posterior circulations. Clinical
findings in stroke are determined by the location of the lesion(s) (Table 161-1), but the degree of collateral
circulation may cause variations in the specific clinical symptoms
and their severity.
161-1 Anterior and Posterior Circulation of the Brain |Favorite Table|Download (.pdf)
161-1 Anterior and Posterior Circulation of the Brain
|Circulation||Major Arteries||Major Regions of Brain Supplied|
|Anterior (internal carotid system)||Ophthalmic||Optic nerve and retina|
|Anterior cerebral||Frontal pole|
|Anteromedial cerebral cortex|
|Anterior corpus callosum|
|Middle cerebral||Frontoparietal ...|