During cortical mastoidectomy for chronic suppurative otitis media with cholesteatoma, the surgeon identifies the lateral semicircular canal (LSCC) as the key surgical landmark. Which relationship of the LSCC to the facial nerve (second genu) is correct?

• A The facial nerve second genu lies inferior and medial to the LSCC ✓
• B The facial nerve second genu lies superior and medial to the LSCC
• C The LSCC is anterior to the stylomastoid foramen at the same depth
• D The horizontal segment of the facial nerve crosses superior to the LSCC

Explanation

The second genu (posterior genu) of the facial nerve lies inferior and medial to the lateral semicircular canal — the LSCC acts as the primary intraoperative landmark to locate the facial nerve. Drilling should proceed inferiorly from the LSCC to find the mastoid segment of the facial nerve. The horizontal (tympanic) segment runs below the LSCC, not superior to it.

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.