Sound Vibrations enter the outer ear (the Pinna). These vibrations pass across the eardrum (Tympanic Membrane) into the middle ear where the sound waves move the three smallest bones in the human body (the Malleus, the Incus and the Stapes.) These vibrations extend into the Cochlea, a small snail-shaped structure that is filled with a liquid that surrounds tens of thousands of microscopic hair cells. The movement of these hair cells stimulates the auditory nerve which then travels to the brain and is interpreted as sound.