A 32-year-old woman develops sudden right-sided Bell's palsy. She also reports decreased salivation on the right side and altered taste from the anterior right tongue. At which level along the facial nerve course is the lesion most likely located?

• A At or proximal to the origin of the chorda tympani (between stylomastoid foramen and origin of chorda tympani)
• B Distal to the stylomastoid foramen in the parotid gland
• C At the genu (geniculate ganglion) or proximal intratemporal segment, above the chorda tympani origin ✓
• D In the internal auditory canal

Explanation

Chorda tympani branches from the facial nerve in the facial canal just proximal to the stylomastoid foramen. A lesion at or proximal to the chorda tympani origin would preserve its function. Taste and salivary function deficits indicate the lesion is proximal enough to involve the chorda tympani — above its departure point in the mastoid segment. A lesion proximal to the chorda tympani (in the vertical mastoid segment or higher, near the geniculate ganglion) would involve chorda tympani fibers and produce these additional features along with facial palsy.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.