A 45-year-old presents with contralateral hemiplegia, hemianesthesia, and homonymous hemianopia, along with thalamic hand posture (flexion of wrist and metacarpophalangeal joints with extension of interphalangeal joints). Lesion at which site produces thalamic hand?

• A Ventral posterolateral (VPL) nucleus of thalamus ✓
• B Posterior limb of internal capsule
• C Red nucleus in midbrain tegmentum
• D Corona radiata superior to basal ganglia

Explanation

Thalamic syndrome (Dejerine-Roussy syndrome) results from infarction of the VPL nucleus of the thalamus (supplied by the thalamogeniculate branches of the posterior cerebral artery). It is characterized by contralateral hemianesthesia initially followed by severe thalamic pain, contralateral choreoathetosis, and the thalamic hand posture — flexion of wrist and MCP joints with hyperextension of IP joints due to loss of thalamic modulation of motor output. The homonymous hemianopia localizes the lesion to the lateral geniculate body territory.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.