Latin: Stapedius muscle
English: stapedius muscle
Synergists: Tensor tympani muscle
The stapes muscle is a middle ear muscle. It protects the ear from high sound levels and thus influences the hearing process. Protection against the volume of one's own voice is particularly important.
It is innervated by the facial nerve and can therefore fail if this nerve is damaged and no longer fulfill its protective function.
The stapedius muscle is the smallest striated muscle in humans.
Approach: Neck area of the stapes
Origin: pyramidal projection (Eminentia pyramidalis)
Innervation: Stapedius nerve of the facial nerve
The stapes muscle is involved in the hearing process. As a rule, it cannot be tensed arbitrarily; its contraction is triggered reflexively at excessively high sound levels. The stapes muscle tensions the annular ligament, a ligament that leads around the stapes footplate.
During contraction, the vibrations of the stapes are weakened and thus transferred to the oval window in a reduced form. From the oval window, vibrations are transmitted to the perilymph, a fluid in the inner ear. Due to the reduced sound transmission, the muscle protects the ear from excessive sound levels.
If the facial nerve is damaged before the stapedius nerve, which supplies the stapes muscle, the stapedius reflex fails and the person concerned is significantly more sensitive to noise. In addition to the sensitivity to noise, there is reduced tear secretion and hemiplegia on one side of the face, since the facial nerve is also responsible for the innervation of the lacrimal gland and the facial muscles.
There are many reasons for such nerve damage. In addition to fractures of the temporal bone, viruses, bacteria, autoimmune diseases of the nervous system or tumors can also lead to lesions of the facial nerve.
The therapy depends on the cause of the disease.