Before becoming recognized by the brain, sound waves must enter via the auditory canal, go through the tympanic membrane (eardrum), and then enter the middle ear compartment. There, sound waves vibrate three bones known as the ossicles, which are made up of the malleus, the incus and the stapes.

The malleus is sometimes compared to a hammer, as it strikes the anvil-shaped incus. Then, the vibrations travel through the stapes.

The stapes can be compared to a tuning fork, as it exhibits a horseshoe-like shape. The two branches, known as the inferior and superior crus, convey sound vibrations to the bone’s flat base. From there, the vibrations enter the inner ear, where it is processed into neural data to be transmitted to the brain via the cochlear and the auditory nerve.

If the stapes becomes damaged, such as what could result from severe head trauma, a person may lose some or all of his or her ability to hear. Since the ossicles are a chain of bones, this also holds true for the incus and malleus bones.