Anatomy and Development of the Tensor Tympani Muscle
- The tensor tympani muscle is located in the middle ear.
- It arises from the cartilaginous part of the auditory tube and the adjacent great wing of the sphenoid.
- It passes through its own canal and ends in the tympanic cavity as a slim tendon that connects to the handle of the malleus.
- The tensor tympani muscle develops from mesodermal tissue in the 1st pharyngeal arch.
Function and Control of the Tensor Tympani Muscle
- The tensor tympani dampens the noise produced by chewing.
- When tensed, it pulls the malleus medially, tensing the tympanic membrane and reducing the perceived amplitude of sounds.
- It can be activated by the startle reflex.
- It can be voluntarily controlled in some individuals.
- Contracting muscles produce vibration and sound.
- Slow twitch fibers produce 10 to 30 contractions per second (equivalent to 10 to 30Hz sound frequency).
- Fast twitch fibers produce 30 to 70 contractions per second (equivalent to 30 to 70Hz sound frequency).
- The sound can be heard by pressing a highly tensed muscle against the ear.
- Voluntary control of the tensor tympani muscle is extremely rare.
Nerve Supply and Trigeminal-Autonomic Activation of the Tensor Tympani Muscle
- The tensor tympani is supplied by the tensor tympani nerve, a branch of the mandibular branch of the trigeminal nerve.
- Activation of the trigeminal nerve can lead to autonomic symptoms.
- Acoustic shock can trigger trigeminal-autonomic activation.
- Substance P and calcitonin gene-related peptide are present in the tensor tympani muscle.
- Activation of these neuropeptides may contribute to trigeminal-autonomic activation.
Disorders and Dysfunctions Associated with the Tensor Tympani Muscle
- Tensor tympani myoclonus is a rare condition characterised by involuntary contractions.
- Symptoms may include clicking sounds in the ear and hearing distortion.
- Tensor tympani syndrome is associated with chronic ear pain and hyperacusis.
- Dysfunction of the tensor tympani muscle may contribute to temporomandibular joint disorders.
- Abnormal contractions of the tensor tympani muscle may be related to certain forms of tinnitus.
Clinical Implications and Treatment Options for Tensor Tympani Muscle Disorders
- Assessment of tensor tympani muscle function can be done through electromyography.
- Treatment options for tensor tympani muscle disorders include muscle relaxants and Botox injections.
- Cognitive-behavioral therapy may be beneficial for patients with tensor tympani syndrome.
- Sound therapy and relaxation techniques can help manage symptoms associated with tensor tympani dysfunction.
- Further research is needed to better understand the role of the tensor tympani muscle in auditory and trigeminal disorders.
The tensor tympani is a muscle within the middle ear, located in the bony canal above the bony part of the auditory tube, and connects to the malleus bone. Its role is to dampen loud sounds, such as those produced from chewing, shouting, or thunder. Because its reaction time is not fast enough, the muscle cannot protect against hearing damage caused by sudden loud sounds, like explosions or gunshots.
| Tensor tympani muscle | |
|---|---|
 | |
| 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 |
| MeSH | D013719 |
| TA98 | A15.3.02.061 |
| TA2 | 2102 |
| FMA | 49028 |
| Anatomical terms of muscle | |
