This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
A positive fistula test during Siegelisation indicates- 
Select and explain. 
A. Ossicular discontinuity, B. Para-labyrinthitis due to erosion of lateral semicircular canal, C. CSF leak through the ear, D. Fixation of stapes bone
B: Para-labyrinthitis due to erosion of lateral semicircular canal
Answer: B: Para-labyrinthitis due to erosion of lateral semicircular canal 
Explanation: Fistula test is done to Assess the Vestibular Function

Basis: In case of fistulous communication between middle ear and labyrinth

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Any pressure change in
External auditory canal (produced by pressing tragus or by siegel’s speculum)
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will stimulate lateral semicircular canal (Ans 11 – Ref Tuli 1/e p. 939)
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Produce nystagmus/vertigo