The commonest site of otosclerosis is -

Ans. is 'd' i.e., Oval window o The most common site of disease is promontory in the region of the anterior margin of oval window, and inadvanced cases the stapes become ankylosed in position by a mass of new spongy bone.Why is it so# This area is involved most commonly because in this area is located the fissula ante fenestram, a vestigial structure which frequently contains cartilaginous remnants and which is particularly prone to otosclerotic changes.o Most common type of otosclerosis - Stapedial otosclerosiso Most common site of otosclerosis - Fissula ante fenestram (i.e, just in front of oval window)o Most common site for stapedial otosclerosis - Fissula ante fenestram (i.e, just in front of oval window)o Most common site for cochlear otosclerosis - Round window