Muscles Associated with Auditory Ossicles

Two muscles dampen or resist movements of the auditory ossicles; one also dampens movements (vibration) of the tympanic membrane.

The tensor tympani is a short muscle that arises from the superior surface of the cartilaginous part of the pharyngotympanic tube, the greater wing of the sphenoid, and the petrous part of the temporal bone. The muscle inserts into the handle of the malleus. The tensor tympani pulls the handle medially, tensing the tympanic membrane and reducing the amplitude of its oscillations. This action tends to prevent damage to the internal ear when one is exposed to loud sounds. The tensor tympani is supplied by the mandibular nerve (CN V₃).

The stapedius is a tiny muscle inside the pyramidal eminence (pyramid), a hollow, cone-shaped prominence on the posterior wall of the tympanic cavity. Its tendon enters the tympanic cavity by emerging from a pinpoint foramen in the apex of the eminence and inserts on the neck of the stapes. The stapedius pulls the stapes posteriorly and tilts its base in the oval window, thereby tightening the anular ligament and reducing the oscillatory range. It also prevents excessive movement of the stapes. The nerve to the stapedius arises from the facial nerve (CN VII).