Sound waves enter the external ear and are funneled toward the tympanic membrane by the shape of the outer ear.Variation in air pressure due to sound waves causes the tympanic membrane to vibrate. The wave frequency will determine the vibration rate.Tympanic vibrations cause the malleus to move. Because the three ossicles are connected, this vibration is transduced to the stapes via the incus.Movement of the stapes vibrates the oval window. Significant amplification of sound waves occurs due to the small size of the window.Pressure changes transduced through the oval window vibrate the perilymph in the scala vestibuli which are transmitted across the vestibular membrane to the endolymph of the cochlear duct, and also up the scala vestibuli and down the scala tympani much the way waves move through the ocean.
