In Bell's palsy (idiopathic facial nerve palsy), the site of maximum nerve oedema is the:
- A Internal auditory meatus
- B Tympanic (horizontal) segment of the fallopian canal
- C Stylomastoid foramen exit point
- D Geniculate ganglion region / meatal foramen at the entrance to the fallopian canal ✓
Explanation
In Bell's palsy, oedema and demyelination occurs along the intratemporal course, but the narrowest point of the fallopian (facial) canal is at the meatal foramen — the transition from the internal auditory meatus to the labyrinthine segment where the canal diameter is smallest (~0.68 mm). Oedema of the nerve at this narrowest point leads to ischaemic compression. Surgical decompression (middle cranial fossa approach) of the labyrinthine segment and meatal foramen gives best results, targeting this exact site. The geniculate ganglion region is the site where herpes simplex virus (HSV-1) reactivation is postulated to occur.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.