Stapedius

The stapedius is the smallest striated muscle in the human body. At just over one millimeter in length, its purpose is to stabilize the smallest bone in the body, the stapes. It prevents excess movement by the stapes, helping to control the conduction of sound waves from the external environment to the inner ear: compare the role of the tensor tympani muscle. Paralysis of the stapedius allows wider oscillation of the stapes, resulting in heightened reaction of the auditory ossicles to sound vibration. Loud noises become deafening.

The stapedius is innervated by a branch of Cranial Nerve VII, the facial nerve.