A 30-year-old patient after parotid surgery develops inability to close the right eye, drooping of the right corner of the mouth, and loss of wrinkling of the right forehead. The lesion is most likely at which level?

• A Upper motor neuron above the pons
• B Extracranial facial nerve distal to stylomastoid foramen ✓
• C Facial nerve within the facial canal
• D Facial motor nucleus in the pons

Explanation

Involvement of all facial muscles on the same side (upper and lower face) indicates a lower motor neuron lesion of the facial nerve. Post-parotid surgery damage is extracranial, distal to the stylomastoid foramen, where the nerve divides into temporal, zygomatic, buccal, marginal mandibular, and cervical branches. An upper motor neuron lesion spares the upper face (forehead) due to bilateral cortical representation. Lesion within the facial canal would also include loss of taste, hyperacusis, or reduced lacrimation depending on the level.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.