Tensor tympani muscle Information & Tensor tympani muscle Links at HealthHaven.com

Tensor tympani muscle
	The right membrana tympani with the hammer and the chorda tympani, viewed from within, from behind, and from above.
	The medial wall and part of the posterior and anterior walls of the right tympanic cavity, lateral view. (Label for "Tensor tympani muscle" is at right, second from bottom.)
	Malleus Tensor Tympani Incus Stapedius Labyrinth Stapes Auditory Canal Tympanic Membrane; (Ear Drum) Eustachian Tube Tympanic cavity
	Bones and muscles in the tympanic cavity in the middle ear
Latin	musculus tensor tympani
Gray's	subject #231 1046
Origin	auditory tube
Insertion	handle of the malleus
Artery	superior tympanic artery
Nerve	medial pterygoid nerve from the mandibular nerve (V3)
Actions	tensing the tympanic membrane

The tensor tympani, the larger of the two muscles of the tympanic cavity, is contained in the bony canal above the osseous portion of the auditory tube. Its role is to dampen sounds produced from chewing.

[edit] Origin and insertion

It arises from the cartilaginous portion of the auditory tube and the adjoining part of the great wing of the sphenoid, as well as from the osseous canal in which it is contained.

Passing backward through the canal, it ends in a slender tendon which enters the tympanic cavity, makes a sharp bend around the extremity of the septum, known as the processus cochleariformis^[1], and is inserted into the manubrium of the malleus, near its root.

[edit] Function

When tensed, the action of the muscle is to pull the malleus medially, tensing the tympanic membrane, damping vibration in the ear ossicles and thereby reducing the amplitude of sounds. This muscle is contracted primarily to dampen the noise produced by chewing. (Compare to the more general dampening function of the stapedius muscle.)

In many people with hyperacusis, an increased activity develops in the tensor tympani muscle in the middle ear as part of the startle response to some sounds. This lowered reflex threshold for tensor tympani contraction is activated by the perception/anticipation of loud sound, and is called tonic tensor tympani syndrome (TTTS). In some people with hyperacusis, the tensor tympani muscle can contract just by thinking about a loud sound. Following exposure to intolerable sounds, this contraction of the tensor tympani muscle tightens the ear drum, which can lead to the symptoms of ear pain/a fluttering sensation/a sensation of fullness in the ear (in the absence of any middle or inner ear pathology)[1][2]. A small percentage of the population can actually voluntarily contract this muscle, inducing a noticeable and (until explained) odd 'rumbling' sound to occur [3][4].

[edit] Innervation

Innervation of the tensor tympani is from the tensor tympani nerve, a branch of the mandibular division of the trigeminal nerve (V). As the tensor tympani is innervated by motor fibres of the trigeminal nerve, it does not receive fibres from the trigeminal ganglion, which has sensory fibres only.

[edit] Additional images

Base of skull. Inferior surface.

External and middle ear, opened from the front. Right side.

View of the inner wall of the tympanum (enlarged.)

Auditory tube, laid open by a cut in its long axis.

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.

[edit] References

^ Clinical Head and Neck and Functional Neuroscience Course Notes, 2008-2009, Uniformed Services University of the Health Sciences School of Medicine, Bethesda, Maryland

[edit] See also

[edit] External links

LUC tt
tensor+tympani+muscle at eMedicine Dictionary
McGill
MadSci Network [5]

This muscle article is a stub. You can help Wikipedia by expanding it.

[0] Clinical Head and Neck and Functional Neuroscience Course Notes, 2008-2009, Uniformed Services University of the Health Sciences School of Medicine, Bethesda, Maryland

[1]

Contents