Ear anatomy. Computer graphic of a section through the skull, showing the anatomy of the human ear. Sound waves are collected by the outer ear pinna (at left) and pass down the auditory canal to strike the eardrum (centre right). Vibrations of sound are transmitted via three tiny ear bones (malleus, incus and stapes) into fluid-filled structures of the inner ear (upper centre right). Three coils of the semi-circular canals detect balance and body orientation. While in the spiral-shaped cochlea, tiny hair cells are sensitive to vibrations of the cochlear fluid and these cells activate the auditory nerve (far right) which is connected to the brain.