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The malleus is a hammer-shaped small bone or ossicle in the middle ear. It is the largest of the three ossicles, measuring about 8cm in length. The tensor tympani muscle attaches to the malleus, and the stapedius muscle attaches to the stapes. The tensor tympani muscle is innervated by a branch of the fifth cranial nerve, while the stapedius is innervated by a branch of the seventh cranial nerve. These muscles receive a dense innervation from motor neurons. The tensor tympani muscle is responsible for reducing the transmission of sound through the middle ear and protecting the ear from loud noises.
| Characteristics | Values |
|---|---|
| Muscle attached to malleus | Tensor tympani (or tensor muscle of the tympanum or malleus) |
| Muscle attached to tensor tympani | Branch of the fifth cranial nerve |
| Muscle attached to stapes | Stapedius |
| Muscle attached to stapedius | Branch of the seventh cranial nerve |
| Function of tensor tympani and stapedius | Dampen sound |
| Tensor tympani location | Attaches to the handle of the malleus |
| Tensor tympani function | Protects the ear from loud and damaging sounds by reducing the amplitude of oscillations |
| Tensor tympani contraction | Pulls the handle of the malleus medially, tensing the tympanic membrane |
| Tensor tympani contraction effect | Reduction of sound transmission through the middle ear |
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What You'll Learn
Tensor tympani muscle attaches at the handle
The tensor tympani is a tiny, long paired muscle of the middle ear. It is one of two muscles that form the ossicular chain, along with the stapedius muscle. The tensor tympani muscle attaches to the malleus at the handle, or manubrium, and dampens the tympanic membrane's vibrations. Tensor tympani contractions move the malleus medially, tightening the tympanic membrane and protecting the ear from loud and damaging sounds.
The tensor tympani muscle arises from the cartilaginous part of the auditory tube, and the adjacent great wing of the sphenoid. It then 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 occupies a bony canal found superior to the osseous part of the auditory tube (pharyngotympanic tube; Eustachian tube). The tensor tympani is innervated by the nerve to medial pterygoid, which arises from the mandibular division of the trigeminal nerve (CNV3).
The tensor tympani's attachment to the malleus, one of the three auditory ossicles, allows tightening of the tympanic membrane, reducing its vibration amplitude and thus reducing the sound transmission into the inner ear. This plays an important role in the tympanic reflex, an evolutionary adaptation to protect the inner ear from excessively loud noises, which also aids speech coordination. The tensor tympani acts to pull the handle of the malleus medially, increasing the tension of the tympanic membrane. This reduces the amplitude of the tympanic membrane oscillations and thereby reduces sound transmission to the vestibular window.
The tensor tympani is one of two middle ear muscles, the other being the stapedius muscle. These muscles are attached to the tympanic membrane and stapes, respectively. The tensor tympani and stapedius are innervated by branches of the 5th and 7th cranial nerves. In humans, the tensor tympani is believed to contract in response to self-generated noise (chewing, swallowing), and the stapedius muscle contracts in response to intense low-frequency sounds.
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Tensor tympani contractions move malleus medially
The tensor tympani is a muscle within the middle ear that connects to the malleus bone. The malleus is the most lateral middle ear ossicle, located between the tympanic membrane and the incus. The tensor tympani muscle attaches to the malleus at the handle and dampens the tympanic membrane's vibrations. Tensor tympani contractions move the malleus medially, pulling the handle of the malleus medially and increasing tension on the tympanic membrane. This reduces the amplitude of the tympanic membrane oscillations and, in turn, reduces sound transmission to the vestibular window, lowering the perceived amplitude of sounds.
The tensor tympani muscle plays a crucial role in various auditory processes, including regulating the movement of the Eustachian tube and stiffening the tympanic membrane to dampen sound transmission in response to high-intensity sounds. This muscle acts to dampen loud sounds, such as those produced from chewing, shouting, or thunder. It is activated by the perception or anticipation of loud sounds and is an evolutionary adaptation to protect the inner ear from excessively loud noises.
The tensor tympani is a tiny but long paired muscle of the middle ear. It occupies a bony canal found superior to the osseous part of the auditory tube (pharyngotympanic tube; Eustachian tube). Its attachment to the malleus, one of the three auditory ossicles, allows for the tightening of the tympanic membrane, reducing its vibration amplitude and, thus, reducing sound transmission into the inner ear.
The tensor tympani muscle is innervated by the mandibular branch of the trigeminal nerve, the fifth cranial nerve (CN V). Spasmodic contractions of the tensor tympani muscle can lead to tensor tympani syndrome (TTS) or tensor tympani myoclonus, a rare condition that results in the perception of a fluttering noise and can cause tinnitus.
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Tensor tympani innervated by branch of mandibular nerve
The tensor tympani is a small, long, paired muscle in the middle ear. It is one of two muscles that form part of the ossicular chain, along with the stapedius muscle. The tensor tympani muscle attaches to the malleus, the largest of the three auditory ossicles, at the handle. This attachment allows the tensor tympani to tighten the tympanic membrane, reducing its vibration amplitude and, therefore, reducing sound transmission into the inner ear.
The tensor tympani is innervated by the nerve to the medial pterygoid, which arises from the mandibular division of the trigeminal nerve (CNV3). The mandibular nerve arises from the trigeminal nerve's third branch. The tensor tympani is supplied by the tensor tympani nerve, a branch of the mandibular branch of the trigeminal nerve. As the tensor tympani is supplied by motor fibres of the trigeminal nerve, it does not receive fibres from the trigeminal ganglion, which has sensory fibres only.
The tensor tympani muscle acts to dampen the noise produced by activities such as chewing, shouting, or thunder. When tensed, the muscle pulls the malleus medially, tensing the tympanic membrane and damping vibration in the ear ossicles, thereby reducing the perceived amplitude of sounds. This is known as the tympanic reflex, an evolutionary adaptation to protect the inner ear from excessively loud noises, which also aids speech coordination.
The tensor tympani muscle originates from the superior surface of the cartilaginous part of the Eustachian tube, the greater wing of the sphenoid, and the petrous part of the temporal bone. It then 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 travels in its canal together with the superior tympanic artery, which supplies it.
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Tensor tympani and stapedius are middle ear muscles
The tensor tympani and stapedius are two muscles of the middle ear. The tensor tympani muscle attaches to the malleus, the most lateral and largest of the three auditory ossicles. The malleus is a small, hammer-shaped bone in the middle ear that transmits sound vibrations from the eardrum to the incus (anvil). The tensor tympani muscle is innervated by a branch of the fifth cranial nerve, and its function is to decrease sound transmission through the middle ear. It achieves this by contracting in response to loud noises, pulling the handle of the malleus medially, and tightening the tympanic membrane. This reduction in the movement of the tympanic membrane results in decreased sound transmission to protect the structures of the internal ear.
The stapedius muscle, on the other hand, attaches to the stapes, the third bone of the auditory ossicles. The stapedius muscle is innervated by a branch of the seventh cranial nerve. Similar to the tensor tympani, the stapedius muscle also contracts in response to loud noises. When it contracts, the stapes is pulled posteriorly, and its base is tilted inside the vestibular window. This action tightens the annular ligament of the stapes, reducing oscillation and preventing excessive movement of the stapes, ultimately dampening sounds.
The tensor tympani and stapedius muscles work together to protect the inner ear from potential damage caused by loud noises. They contract in response to loud sounds, reducing the transmission of sound vibrations through the ossicular chain and decreasing the amplitude of oscillations. This protective mechanism is particularly important for preserving the delicate structures within the inner ear, which are sensitive to excessive sound pressure and vibrations.
In summary, the tensor tympani and stapedius muscles are integral components of the middle ear, playing a crucial role in modulating sound transmission and protecting the inner ear from potential damage caused by loud noises. Their coordinated contractions in response to loud sounds help to safeguard the auditory system and maintain optimal hearing function.
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Tensor tympani and stapedius dampen loud sounds
The tensor tympani and stapedius muscles play a crucial role in dampening loud sounds to protect the ear from potential damage. The tensor tympani is a muscle within the middle ear, located in the bony canal above the bony part of the auditory tube. It connects to the malleus bone, which is the largest of the three ossicles in the middle ear cavity. The tensor tympani muscle contracts in response to loud sounds, pulling the manubrium of the malleus inwards and tightening it. This contraction helps to dampen the sound vibration that reaches the cochlea.
The stapedius muscle also contributes to dampening loud sounds. It is attached to the stapes, the third ossicle in the middle ear cavity. When sounds become loud, the stapedius muscle contracts along with the tensor tympani, moving the stapes posteriorly. This action helps to stabilize the ossicles and reduce their vibration, thereby reducing the perceived volume.
The contraction of the tensor tympani and stapedius muscles is known as a middle ear muscle reflex or acoustic reflex. These reflexes are important for protecting the delicate inner ear from damage caused by excessive sound vibrations. However, it is important to note that these muscles have a relatively slow reaction time and may not be able to protect against sudden loud noises, such as explosions or gunshots.
In some individuals, the tensor tympani muscle can exhibit involuntary contractions, a condition known as tensor tympani syndrome (TTS) or tensor tympani myoclonus. This rare disorder can result in tinnitus, a perception of rhythmic sounds that can be heard by both the affected individual and others during an episode. TTS is characterized by spasmodic contractions of the tensor tympani muscle, which can be triggered by loud noises, stress, anxiety, or certain physiological actions like chewing or swallowing.
Additionally, hyperacusis, an increased sensitivity to normal levels of loudness, can be associated with heightened activity in the tensor tympani muscle. This heightened activity is known as tonic tensor tympani syndrome (TTTS) and can lead to symptoms such as ear pain, a fluttering sensation, or a feeling of fullness in the ear.
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Frequently asked questions
The tensor tympani muscle and the stapedius muscle.
The tensor tympani muscle attaches to the malleus to prevent excessive oscillations produced by loud sounds.
The stapedius muscle dampens sounds through its attachment to the stapes.
