Origin: Interior of pyramid of tympanic cavity
Insertion: Posterior surface of neck of stapes
Nerve: Facial nerve
Action: Control the amplitude ofsound waves to the inner ear
The Stapedius arises from the wall of a conical cavity, hollowed out of the interior of the pyramidal eminence; its tendon emerges from the orifice at the apex of the eminence, and, passing forward, is inserted into the posterior surface of the neck of the stapes. It is supplied by a branch of the facial nerve.
Actions.—The Stapedius pulls the head of the stapes backward and thus causes the base of the bone to rotate on a vertical axis drawn through its own center; the back part of the base is pressed inward toward the vestibule, while the forepart is withdrawn from it. By the action of the muscle the tension of the fluid within the internal ear is probably increased.