Two patients have complete unilateral LMN facial palsy. Patient 1 also has hyperacusis and loss of taste on the anterior two-thirds of the tongue. Patient 2 has no hyperacusis and normal taste. In Patient 2, the lesion is located distal to which structure?

• A Geniculate ganglion
• B Chorda tympani branch point in the middle ear
• C Internal acoustic meatus
• D Origin of the nerve to stapedius ✓

Explanation

Hyperacusis results from paralysis of stapedius, whose nerve leaves the facial canal near the pyramidal eminence, just proximal to the stylomastoid foramen. Taste loss localizes the lesion proximal to the chorda tympani origin. A patient with neither finding must have a lesion distal to the origin of the nerve to stapedius, such as at or beyond the stylomastoid foramen. Lesions at the geniculate ganglion or meatus produce both deficits.

Reference: Gray's Anatomy for Students, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.