<prompt> Otosclerosis typically begins atScutumRound windowTympanic membraneFistula antefenestrum  <response>: Ans. d Fistula antefenestrum Ref. Bhargava ENT 6th ed., p 76; PL Dhingra, 3rd ed., p 114 in otosclerosis, the oval window is involved in 85 of cases and the round window in 15, respectively, with otosclerosis and conductive deafness. Infact, the commonly involved site is the anterior oval window region fistula ante fenestrum.OTOSCLEROSIS Introduction:- Otosclerosis otospongiosis refers to a condition where the enchondral bone around the otic capsule is replaced by multiple foci of spongy vascular irregular bone. The spongy bone later becomes calcified and sclerotic. Etiology location:- 70 familial, autosomal dominant. 0- F: M - 3: 1; more common in pregnancy.- Age of onset 20-30 yrs- White races. Clinical features:- Deafness, conductive in cochlear, sensorineural loss is present, Tinnitus.- Ear drum: Normal- In active otosclerosis, pink patch Flamingo tint present over promontory Schwartz Sign, i.e., Schwartz sign is Red hue may be seen through the tympanic membrane of promontory.- Paracusis Willisi Patient hears better in noisy surroundings 0- Depression in audiogram and Carharts notch. 0- Reduced compliance at ambient pressure, i.e., type As tympanogram is diagnostic. Q CT scan:- Otosclerosis is divided into two types: Fenestral Otosclerosis- Fenestral otosclerosis is the most common form and involves the oval window and the footplate of the stapes. Imaging Finding is a subtle bony rarefaction at the anterior wall of the oval window. Retrofenestral Cochlear Otosclerosis- It presents as a sensorineural or mixed hearing loss. On CT scanning, a ring of lucency around the cochlea is characteristic of it double ring sign-- Diagnosis of otosclerosis is usually based on clinical audiologic findings, CT is rarely indicated. Medical treatment of otosclerosis- Sodium fluoride- Indication: Cochlear otosclerosis- It reduces osteosclerotic bone resorption.- It has anti-enzymatic action on proteolytic enzymes, which are cytotoxic to cochlear cells Surgical treatment- Fenestration operation- Mobilization of stapes- Stapedectomy Treatment of choice- Indications: Otosclerosis with bone conduction level of 0-25 dB speech range and air conduction 45-65 dB. Air-bone gap should be at least 20 dB. 