Stapedius

Musculus stapedius

Sensory (eye & ear)Deep musclesHeadLeft and right

View left in 3D View right in 3D

What it is
The smallest skeletal muscle in the body, hidden inside the pyramidal eminence on the back wall of the middle ear; only its tendon emerges, to attach to the neck of the stapes.
Function
Tilts the stapes to stiffen the ossicular chain: the acoustic reflex that protects the inner ear from loud sounds.
Size
About 6 mm long and 1 mm wide.
Clinical note
Paralysed in Bell's palsy (facial nerve, CN VII), causing hyperacusis: ordinary sounds seem uncomfortably loud.

Nearby sensory (eye & ear) structures Cochlea, Cochlear duct, Incus, Lateral semicircular canal, Middle ear cavity, Oval window, Posterior semicircular canal, Round window, Scala tympani, Stapes