stapes

The tympanic cavity is spanned by the three smallest bones in the body: the auditory ossicles[…] These bones, named for their shape, are the malleus (malʹe-us; "hammer"); the incus (ingʹkus; "anvil"); and the stapes (staʹpēz; "stirrup"). The "handle" of the malleus is secured to the eardrum, and the base of the stapes fits into the oval window.