During cochlear implantation, the surgeon drills a posterior tympanotomy (facial recess) to gain access to the middle ear from the mastoid. Which of the following correctly describes the boundaries of the facial recess?

• A Facial nerve laterally, chorda tympani medially, lateral semicircular canal superiorly
• B Sigmoid sinus posteriorly, tegmen superiorly, digastric ridge inferiorly
• C Facial nerve medially, chorda tympani laterally, incus buttress superiorly ✓
• D Tegmen superiorly, sinodural angle posteriorly, external auditory canal anteriorly

Explanation

The facial recess lies between the vertical (mastoid) segment of the facial nerve medially, the chorda tympani nerve laterally, and the incus buttress (short process of incus) superiorly. Opening this triangle gives access to the round window niche for electrode insertion. Option B describes the cortical mastoidectomy limits, not the recess. The key distractor A reverses the facial nerve and chorda tympani positions, which would risk facial palsy if followed intraoperatively.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.