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Which artery supplies the territory that explains this deficit?
More, if you want it
Where does the patient have the stroke signs?Tap a term: its definition, what you can do with it, and how often the exam asks it.
Definition: a blocked ACA, weakening the opposite leg and foot most.
You can: Tell anterior cerebral artery occlusion from middle cerebral artery occlusion by whether the leg is weaker than the arm and face.
Definition: a blocked MCA, weakening the opposite face and arm most.
You can: Tell middle cerebral artery occlusion from anterior cerebral artery occlusion by face and arm weakness with aphasia.
Definition: lateral medulla damage from a blocked PICA.
You can: Tell Wallenberg syndrome from locked-in syndrome by whether the patient can still move and speak.
Definition: paralysis and loss of speech with full consciousness, from ventral pons damage.
You can: Tell locked-in syndrome from akinetic mutism by the site of the brainstem lesion.
Each card is one term. The grey line is what the patient says, which is what the question stem gives.
Summary
Anterior cerebral artery occlusion causes contralateral leg-predominant weakness, with the leg and foot weaker than the arm and face.
causes contralateral leg-predominant weakness, with the leg and foot weaker than the arm and face. The anterior cerebral artery (ACA) supplies the medial motor strip, the strip of cortex that moves the leg. Bilateral medial frontal involvement can add , and urinary incontinence.
Akinetic mutism means no voluntary movement or speech in a patient who looks alert from eye movements. Akinetic mutism also occurs in psychotic depression and catatonic states. Limb weakness from cerebrovascular disease is typically asymmetrical, so the clinician compares the two sides. Abulia is a loss of will to start actions.
Wei Chen arrives at a hyper-acute stroke unit. Wei says, "My right leg gave way, and my foot drags."
The is supplied mostly by the ACA, through the pericallosal artery. The middle and posterior cerebral arteries are not its main supply.
Pure callosal lesions are hard to spot at the bedside. Specialised neuropsychological testing shows the disconnection syndrome. In a disconnection syndrome, each hemisphere still works but cannot pass information to the other. The corpus callosum is the band of fibres joining the two hemispheres.
Analogy
The brain is a town, and each artery is a water main feeding its own streets. The ACA main feeds the middle streets, the leg area. The MCA main feeds the side streets, the face and arm area. A blocked main dries the taps in its streets only.
Where the analogy breaks: a dry street affects its own houses, but a blocked artery weakens the opposite side of the body.
5 more sections on Cerebral arterial territories: ACA, MCA, Wallenberg and locked-in syndromes
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