The earliest and most common site of the otosclerotic focus in the temporal bone is:

• A Round window niche
• B Incudostapedial joint
• C Cochlear aqueduct
• D Fissula ante fenestram ✓

Explanation

The fissula ante fenestram, a zone of immature cartilage just anterior to the oval window, is the site of the initial otosclerotic lesion in the vast majority of ears. Disease here fixes the anterior stapes footplate, giving the classic conductive loss. The round window may be involved later in extensive disease, and the incudostapedial joint is not an otosclerotic site, which eliminates options A and B.

Reference: Dhingra's Diseases of Ear, Nose and Throat, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.