The middle ear lies at the end of the auditory canal. It is composed of the eardrum and three small bones, known by the layman as the hammer, the anvil and the stirrup. When sound waves hit the eardrum, it vibrates and, in turn, moves the hammer. The hammer moves the anvil, which moves the stirrup, transmitting the vibrations into the inner ear. The middle ear functions to amplify sound, which is why significant hearing loss can result from any disruption in any of the parts.