<prompt> Mc Ewan triangle is formed by all except:Posterosuperior bony canal wallTemporal lineFloor of bony canal wallTangential line drawn to the EAC  <response>: McEwans triangle is bounded by temporal line, postero-superior canal wall and a tangential line to the external auditory canal. This triangle segment overlies mastoid antrum. This is an important anatomical landmark in mastoid surgery. 