An infarction of which region typically causes ipsilateral abducens nerve palsy and contralateral weakness?

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Multiple Choice

An infarction of which region typically causes ipsilateral abducens nerve palsy and contralateral weakness?

A lesion in the ventral pons best explains this pattern. The abducens nucleus and the nerve fibers that innervate the lateral rectus lie in the caudal pons, and the corticospinal tract runs nearby in the basis pontis. An infarct there disrupts the ipsilateral abducens nerve/fascicles, causing an inability to abduct the affected eye, while also interrupting the corticospinal tract fibers that cross to control the opposite side of the body, producing contralateral weakness. Other brainstem or cortical strokes don’t typically produce this exact combination of ipsilateral cranial nerve VI palsy with contralateral motor weakness.

A lesion in the ventral pons best explains this pattern. The abducens nucleus and the nerve fibers that innervate the lateral rectus lie in the caudal pons, and the corticospinal tract runs nearby in the basis pontis. An infarct there disrupts the ipsilateral abducens nerve/fascicles, causing an inability to abduct the affected eye, while also interrupting the corticospinal tract fibers that cross to control the opposite side of the body, producing contralateral weakness. Other brainstem or cortical strokes don’t typically produce this exact combination of ipsilateral cranial nerve VI palsy with contralateral motor weakness.

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