Question

Regarding anterior choroidal artery syndrome, all are true except?

• A. Hemiparesis
• B. Hemisensory loss
• C. Predominant involvement of anterior limb of internal capsule
• D. Homonymous hemianopia

Hint:

The anterior choroidal artery supplies the posterior limb of the internal capsule, not the anterior limb.

Answer 1

The Correct Option is C

Step 1: Identify the vascular territory. The anterior choroidal artery is a branch of the internal carotid artery. It supplies the posterior limb of the internal capsule, the optic tract and lateral geniculate body, and parts of the medial temporal lobe.
Step 2: Map the territory to the clinical triad. Damage to the posterior limb of the internal capsule and adjacent structures produces the classic anterior choroidal artery syndrome triad: contralateral hemiplegia or hemiparesis (corticospinal fibres in the posterior limb), contralateral hemianesthesia or hemisensory loss (thalamocortical sensory fibres), and contralateral homonymous hemianopia (optic tract or lateral geniculate body).
Step 3: Test each option. Hemiparesis is true. Hemisensory loss is true. Homonymous hemianopia is true. The statement that there is predominant involvement of the ANTERIOR limb of the internal capsule is false, because the anterior choroidal artery supplies the POSTERIOR limb, not the anterior limb.
Step 4: Note the supply of the anterior limb for contrast. The anterior limb is supplied mainly by the lenticulostriate branches of the middle cerebral artery and the recurrent artery of Heubner from the anterior cerebral artery.
Conclusion: The exception is predominant involvement of the anterior limb of the internal capsule, so the correct answer is option 3.