Which anatomical site is the most common location of the primary otosclerotic focus?

• A Round window niche
• B Cochlear aqueduct
• C Fissula ante fenestram ✓
• D Promontory near the tensor tympani canal

Explanation

The fissula ante fenestram, a strip of cartilage anterior to the oval window, is the commonest site of the initial otosclerotic focus. Fixation of the stapes footplate follows when the focus extends across the annular ligament. The round window and cochlear endosteum may be involved later in cochlear otosclerosis, but they are secondary sites, not the usual point of origin.

Reference: Scott-Brown's Essential Otorhinolaryngology, 1st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.