There is a small lucency anterior to the vestibule, just lateral to the basal turn of the cochlea. Consistent with fenestral otosclerosis.
There are two types of otosclerosis:
1- Fenestral: is the most common type. It involves the bone anterior to the oval window and causes conductive hearing loss.
2- Retro-fenestral: involves the cochlear capsule and causes sensorineural hearing loss.
The two types can occur simultaneously.