The Full Wiki

Advertisements

More info on Tensor tympani

Tensor tympani: Wikis

Advertisements

Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.

Encyclopedia

Advertisements
(Redirected to Tensor tympani muscle article)

From Wikipedia, the free encyclopedia

Tensor tympani muscle
Gray912.png
The right membrana tympani with the hammer and the chorda tympani, viewed from within, from behind, and from above.
Musculustensortympani.png
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.)
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.

Contents

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.

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].

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.

Additional images

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.

References

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

See also

External links


Tensor tympani
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.)
Tensor Tympani
Tympanic Membrane
(Ear Drum)
Eustachian Tube
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, from which it is separated by the septum canalis musculotubarii.

Contents

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.

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].

Innervation

Innervation of the muscle is from branches of the mandibular division (moreover, the tensor tympani nerve) of the trigeminal motor nerve (V), by way of the Trigeminal ganglion.

Additional images

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 As such, some of the information contained herein may be outdated.

References

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

See also

External links

Template:Auditory system


Advertisements






Got something to say? Make a comment.
Your name
Your email address
Message