<prompt> Mc Ewans triangle is located onMastoid antrumInner earCochleaSaccule  <response>: MacEwens 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 6e,p 6. 