During cortical mastoidectomy for cholesteatoma, the surgeon encounters a dense bony plate deep to the mastoid cortex and mistakes it for the posterior canal wall, stopping dissection prematurely. Disease is later found to persist in a deeper cell tract. This bony barrier is called:

• A Macewen's triangle
• B Citelli's ridge
• C Henle's spur
• D Körner's septum ✓

Explanation

Körner's septum is a persistent petrosquamous lamina that divides the mastoid into a shallow superficial part and a deeper true mastoid antrum. An inexperienced surgeon may mistake it for the posterior canal wall and abandon dissection, leaving cholesteatoma behind in the deeper cells. Henle's spur and Macewen's triangle are surface landmarks on the lateral cortex used to start the drilling, while Citelli's ridge relates to the sinodural angle, none of which lie deep within the pneumatized bone.

Reference: Scott-Brown's Essential Otorhinolaryngology, 3rd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.