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list the two muscles of the middle ear.
what is their function?
where do they originate from?
what does each one do?
what are their innervations?
what is their function?
where do they originate from?
what does each one do?
what are their innervations?
tensor tympani and stapedius
-act to dampen movements of the auditory ossicles, and tensor tympani also dampens vibration of the tympanic membrane.
Tensor tympani originates 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, and inserts onto the handle of the malleus.
- acts to pull the handle medially, thereby tensing the tympanic membrane and reducing the amplitude of its oscillations, and in this way preventing damage to the internal ear by loud sounds.
- stapedius tendon emerges from a tiny foramen at the apex of the eminence and inserts onto the neck of the stapes.
- acts to pull the stapes posteriorly and tilt its base
(footplate) in the oval window, tightening the annular ligament by which the ossicle is attached, and thereby reducing the oscillatory range.
- prevents excessive movement of stapes.
stapedius: the nerve to stapedius, a branch of the facial nerve
tensor tympani: is supplied by the motor root of the
trigeminal nerve running with its mandibular division (V3).
-act to dampen movements of the auditory ossicles, and tensor tympani also dampens vibration of the tympanic membrane.
Tensor tympani originates 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, and inserts onto the handle of the malleus.
- acts to pull the handle medially, thereby tensing the tympanic membrane and reducing the amplitude of its oscillations, and in this way preventing damage to the internal ear by loud sounds.
- stapedius tendon emerges from a tiny foramen at the apex of the eminence and inserts onto the neck of the stapes.
- acts to pull the stapes posteriorly and tilt its base
(footplate) in the oval window, tightening the annular ligament by which the ossicle is attached, and thereby reducing the oscillatory range.
- prevents excessive movement of stapes.
stapedius: the nerve to stapedius, a branch of the facial nerve
tensor tympani: is supplied by the motor root of the
trigeminal nerve running with its mandibular division (V3).
