<prompt> Scutum isBony pa of outer attic wallBony pa of inner attic wallCailaginous pa of outer attic wallCailagenous pa of inner attic wall  <response>: The lateral wall of the middle ear is formed largely by the tympanic membrane and to a lesser extent by the bony outer attic wall called the scutum.Refer: PL Dhingra, Diseases of Ear, Nose Throat, 7th edition, pg no. 6 