Anatom3DStapedius
Musculus stapedius · Třmínkový sval
Muscles
Looks like
The smallest skeletal muscle in the body, about 6 mm long, hidden in a bony canal behind the middle ear and attached to the neck of the stapes; supplied by the facial nerve.
What it does
Contracts within a fraction of a second to loud sounds, stiffening the stapes and damping what reaches the inner ear (the acoustic reflex).
Keeping it well
In Bell's palsy it is paralysed, so ordinary sounds become painfully loud (hyperacusis) on that side. The acoustic reflex test on a hearing check shows where along the pathway damage lies.