Nasal Cavity, Sinuses and Ear - LO 4

4. What are the two muscles of the middle ear? How are these muscles innervated?

The muscles of the middle ear that associate with the ossicles include the tensor tympani m. and the stapedius m. The tensor tympani m. is attached to the manubrium (handle) of the malleus and pulls it medially to make the tympanic membrane more tense, thereby reducing the amplitude of its oscillations that could lead to damage to the inner ear when hearing loud sounds. It is innervated by the nerve to tensor tympani. of V3. The tendon of the stapedius m. attaches to the stapes at the neck, where it can pull the stapes posteriorly, thereby tilting the base of the stapes in the oval window. This will tighten the anular ligament and reduce the oscillatory range. Stapedius m. is innervated by the nerve to the stapedius of CN VII.