Most common site for the initiation of otosclerosis is -: (A) Foot plate of stapes, (B) Margins of stapes, (C) Fissula ante fenestram, (D) Fissula post fenestram
Answer is C. Most common type of otosclerosis – Stapedial otosclerosis
Most common site of otosclerosis – Fissula ante fenestram (i.e. just in front of oval window)
Most common site for stapedial otosclerosis – Fissula ante fenestram (i.e. just in front of oval window)
Most common site for cochlear otosclerosis – Round window

Ref. Dhingra 5/e, p 97-98, 6/e, p 86-87