Tensor tympani

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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.)
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 (V)
Action:
Dorlands/Elsevier	m_22/12551096

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. (The other muscle in this cavity is the very small stapedius.)

1 Origin and insertion
2 Function
3 Innvervation
4 Additional images
5 External links

[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, 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.)

[edit] Innvervation

Innervation of the muscle is from branches of the mandibular division of the trigeminal nerve (V3), by way of the Otic ganglion.

[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 As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.