A 65-year-old man presents with acute onset of right-sided weakness and facial drooping. He can wrinkle his forehead normally but cannot smile or close his mouth on the right. This pattern localizes the lesion to

• A Right facial nerve (peripheral palsy)
• B Right neuromuscular junction
• C Right facial nerve nucleus in pons
• D Left motor cortex or corticobulbar tract ✓

Explanation

Upper motor neuron facial palsy spares the forehead because the upper facial muscles receive bilateral cortical innervation. Only the lower face is weak, with inability to smile or puff cheeks, while forehead wrinkling is preserved. This localizes to the contralateral motor cortex or corticobulbar tract. LMN palsy (Bell palsy, nuclear, or nerve lesion) would cause complete ipsilateral facial weakness including the forehead.

Reference: Clinical Neurology (Bradley), 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.