During cochlear implant surgery, the facial nerve is at risk in the mastoid segment. The vertical (mastoid) segment of the facial nerve runs between which two landmarks?

• A Between the digastric ridge and the stylomastoid foramen ✓
• B Between the lateral semicircular canal and the fossa incudis
• C Between the pyramidal eminence and the chorda tympani origin
• D Between the tympanomastoid suture and the digastric ridge

Explanation

The vertical (mastoid) segment of the facial nerve descends from the second genu (at the level of the pyramidal eminence and horizontal semicircular canal) to the stylomastoid foramen. The digastric ridge is an important surgical landmark pointing to the stylomastoid foramen where the nerve exits. The lateral semicircular canal and fossa incudis are more superior landmarks related to the second genu, not the full vertical segment.

Reference: Cummings Otolaryngology: Head and Neck Surgery, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.