During a canal wall-up mastoidectomy for unsafe CSOM with cholesteatoma, which surgical landmark is used to identify the level of the tegmen plate and prevent intracranial entry?

• A MacEwen's suprameatal triangle ✓
• B Henle's spine
• C Macewen's cribriform area
• D Fossa incudis

Explanation

MacEwen's suprameatal triangle (posterior triangle) is the key surface landmark posterior to the spine of Henle, through which the mastoid antrum is accessed. It sits just behind the ear canal and its superior boundary corresponds to the level of the tegmen. Henle's spine is the anterior wall landmark, not a guide for tegmen depth. The fossa incudis is an internal landmark indicating short process of incus position.

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.