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
Cholesteatoma commonly perforates - 
Select and explain. 
A. Lat. semicircular canal, B. Sup. semicircular canal, C. Promontory, D. Oval window
A: Lat. semicircular canal
Answer: A: Lat. semicircular canal 
Explanation: Cholesteatoma has the property to destroy the bone by virtue of the various enzymes released by it.
Structures immediately at the risk of erosion are:

– Long process of incus.Q
– Fallopian canal containing facial nerve. Q
– Horizontal/lateral semicircular canal. Q