Anatomy of the human ear, illustration. Sound waves are collected by the ear pinna (at left) and pass down an auditory canal to strike the eardrum. Vibrations are transmitted via three tiny ear bones (inset: malleus, incus and stapes) into fluid-filled structures of the inner ear (blue). Three coils of the semi-circular canals detect balance and body orientation. In the cochlea (spiral), tiny hair cells are sensitive to vibrations of the cochlear fluid and these activate nerves which connect to the brain. Thus, a sense of hearing results from the conduction of sound waves through air, bone and fluid in the ear.