Three Tiny Bones in Your Ear Make Sounds Louder

Hearing depends on a chain of small moving parts. The National Institute on Deafness and Other Communication Disorders, part of the U.S. National Institutes of Health, describes the steps. Sound waves enter the outer ear and travel through the ear canal to the eardrum. The eardrum vibrates and sends these vibrations to three tiny bones in the middle ear, called the malleus, incus and stapes. According to the institute, these bones amplify, or increase, the sound vibrations and send them to the cochlea, a snail-shaped structure filled with fluid in the inner ear. There the vibrations make the fluid ripple, and sensory cells called hair cells turn the movement into an electrical signal. The auditory nerve carries this signal to the brain, which turns it into a sound that we recognize and understand.