A 55-year-old man with hypertension wakes up with a right hemiplegia and homonymous hemianopia without any cortical signs (aphasia, agnosia, neglect). The lesion is most likely located in which structure?

• A Left MCA territory — cortical (superior division)
• B Left thalamus
• C Right basal ganglia
• D Left posterior limb of the internal capsule / posterior limb capsular territory ✓

Explanation

Pure motor + visual field deficit (pure motor stroke + hemianopia) without cortical signs (language, attention, calculation) suggests a subcortical lacunar infarct involving the posterior limb of the internal capsule, where corticospinal and optic radiation fibers run compactly. Pure motor lacunar syndrome involves just the internal capsule/corona radiata. MCA cortical infarcts cause cortical signs (aphasia if dominant). Thalamic infarcts cause sensory predominance rather than motor. This is a classic lacunar small-vessel territory stroke.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.