In a patient with CSOM, labrynthine fistula most commnonly involves ?

Ans. is 'b' i.e., Lateral SCC Labrynthine fistula is almost exclusively repoed in association with chronic otitis media and cholesteatoma. The most commonly affected canal is lateral (horizontal) semicircular canal, but involvement of the posterior and superior canals as well as other regions of labyrinth have been repoed. The incidence of labrynthine fistula in chronic otitis media is approximately 10%.