The middle ear includes the tympanum proper, which is crossed by the chain of ossicles-malleus, incus, and stapes-the Eustachian tube, which communicates with the naso-pharynx, and the tympanic antrum and mastoid cells.
"Manual of Surgery Volume Second: Extremities--Head--Neck. Sixth Edition."
Alexander Miles Alexis Thomson
2. The area of the membrana tympani is about twenty times as great as the membrane of the internal ear which is acted upon by the stapes.
"Physiology and Hygiene for Secondary Schools"
Francis M. Walters, A.M.
Sound waves enter the liquids of the internal ear at this point, the foot of the stapes being attached to the membrane.
"Physiology and Hygiene for Secondary Schools"
Francis M. Walters, A.M.