<prompt> Narrowest part of middle ear is -HypotympanumEpitympanumAtticMesotympanum  <response>: When seen in coronal section, the cavity of the middle ear is biconcave, as the medial and lateral walls are closest to each other in the center.The distances separating them are:Near the roof 6 mm Epitympanum AtticIn the centre 2 mm Mesotympanum between promontary and umboNear the floor 4 mm Hypotympanum 