What separates the outer ear from the middle ear?

The outer ear is separated from the middle ear by the external auditory canal. At the end of the canal lies the eardrum, known medically as the tympanic membrane.

The external portion of the ear, called the pinna, is made up of cartilage and functions to funnel sound into the auditory canal. From there, sound waves cause the vibration of the tympanic membrane, which is connected to three small bones within the middle ear. These bones vibrate to transmit the sound to the inner portion of the ear, allowing it to reach the cochlear. From the cochlear, the vibrations are converted into nerve impulses that travel down the auditory nerve to the brain.