This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
Mc Ewans triangle is located on 
Select and explain. 
A. Mastoid antrum, B. Inner ear, C. Cochlea, D. Saccule
A: Mastoid antrum
Answer: A: Mastoid antrum 
Explanation: MacEwen's triangle is bounded by temporal line,posterosuperior segment of bony external auditory canal and the line drawn as a tangent to the external canal. It is an impoant landmark to locate the mastoid antrum in mastoid surgery. Reference-Dhingra 6/e,p 6.