A 60-year-old hypertensive man presents with acute onset of loss of pain and temperature sensation over the right face, arm, and leg without any motor weakness. MRI shows a small lacunar infarct. The most likely site of the lesion is

• A Left posterior limb of internal capsule
• B Left paracentral lobule
• C Right basis pontis
• D Left thalamus (VPL nucleus) ✓

Explanation

Pure sensory stroke results from a lacunar infarct in the ventral posterolateral (VPL) nucleus of the thalamus. The VPL nucleus is the sensory relay station carrying spinothalamic and medial lemniscal fibers. Posterior limb of internal capsule lesions cause pure motor hemiparesis. A pontine lesion would cause crossed or ataxic hemiparesis syndromes. The paracentral lobule supplies the leg area of motor and sensory cortex.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.