This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CSOM and its Complications, Subject name: ENT
In a patient with CSOM, labrynthine fistula most commnonly involves - 
Select and explain. 
A. Superior SCC, B. Lateral SCC, C. Posterior SCC, D. Utricle
B: Lateral SCC
Answer: B: Lateral SCC 
Explanation: Ans. is 'b' i.e., Lateral SCC o Labrynthine fistula is almost exclusively reported in association with chronic otitis media and cholesteatoma,o 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 reported,o The incidence of labrynthine fistula in chronic otitis media is approximately 10%.