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The ossicles are, in order from the eardrum to the inner ear, the hammer, anvil, and stirrup, so named because of the shape of the bones. They are also commonly referred to by the equivalent Latin terms: malleus, incus, and stapes respectively.

The incus is connected to both the other bones. The malleus articulates with the incus and is attached to the eardrum, from which vibrational energy is passed. The stapes articulates with the incus and is attached to the membrane of the fenestra ovalis, the elliptical or oval window or opening between the middle ear and the vestibule of the inner ear.

As sound waves vibrate the eardrum ( tympanic membraneThe tympanic membrane or eardrum, is a thin membrane at the end of the ear canal that constitutes the boundary between the outer ear and the middle ear. The eardrum converts the air borne sound into mechanical vibrations of the ossicles which then transmi), it in turn moves the nearest ossicle, the malleus to which it is attached. The malleus then transmits the vibrations, via the incus, to the stapes, and so ultimately to the membrane of the fenestra ovalis, the opening to the vestibule of the inner ear.

The ossicles give the eardrum mechanical advantageIn physics and engineering mechanical advantage (MA is the factor by which a machine multiplies the force put into it. The mechanical advantage can be calculated for the following simple machines by using the following formulas: Lever: MA length of effort; the resulting vibrations would be much smaller if the sound waves were transmitted directly from the outer ear to the oval window. However, the extent of the movements of the ossicles is controlled (and constricted) by certain muscles attached to them (the tensor tympani and the stapedius ) in order to protect the inner ear from excessively loud noise (see acoustic reflexThe acoustic reflex is an involuntary muscle contraction that occurs in the middle ear of mammals in response to loud sound stimuli. When presented with a loud sound stimulus, the stapedius and tensor tympani muscles of the ossicles contract. The stapediu).