Tensor tympani muscle

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.)
Details
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
Identifiers
Latin	Musculus tensor tympani
TA	A15.3.02.061
FMA	49028
Anatomical terms of muscle []

The tensor tympani is a muscle within the ear. It is contained in the bony canal above the osseous portion of the auditory tube. Its role is to dampen sounds, such as those produced from chewing.

The tensor tympani 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, and is inserted into the neck of the malleus, near its root.

The tensor tympani is the larger of the two muscles of the tympanic cavity, the other being the stapedius.

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

The tensor tympani muscle develops from mesodermal tissue in the 1st pharyngeal arch.

The tensor tympani acts to dampen the noise produced by chewing. When tensed, the muscle pulls the malleus medially, tensing the tympanic membrane and damping vibration in the ear ossicles and thereby reducing the perceived amplitude of sounds.

Contracting muscles produce vibration and sound. Slow twitch fibers produce 10 to 30 contractions per second (equivalent to 10 to 30 Hz sound frequency). Fast twitch fibers produce 30 to 70 contractions per second (equivalent to 30 to 70 Hz sound frequency). The vibration can be witnessed and felt by highly tensing one's muscles, as when making a firm fist. The sound can be heard by pressing a highly tensed muscle against the ear, again a firm fist is a good example. The sound is usually described as a rumbling sound. A very small percentage of individuals can voluntarily produce this rumbling sound by contracting the tensor tympani muscle of the middle ear. The rumbling sound can also be heard when the neck or jaw muscles are highly tensed as when yawning deeply. This phenomenon has been known since (at least) 1884.