Which artery is commonly affected in strokes presenting with contralateral extremity weakness where lower extremities are affected more than upper ones?

The anterior cerebral artery is commonly affected in strokes that present with contralateral extremity weakness, particularly when the lower extremities are affected more than the upper ones. This is due to the specific area of the brain supplied by the anterior cerebral artery, which predominantly feeds the medial surfaces of the frontal and parietal lobes. These regions control motor function for the lower limbs, leading to scenarios where patients exhibit more significant weakness in the legs than in the arms when a stroke occurs in this territory.

Additionally, the anterior cerebral artery is responsible for supplying parts of the motor cortex that map to the lower extremities; hence, occlusion here will result in deficits primarily in the legs. This characteristic of presenting with greater lower limb weakness is a classic clinical finding associated with anterior cerebral artery strokes, distinguishing them from conditions involving other cerebral arteries.