Smallest human bone – which one it is – Animus Medicus GmbH Skip to content
Was ist der kleinste Knochen des Menschen? - Animus Medicus GmbH

What is the smallest human bone?

A healthy adult human has approximately 200 bones. The smallest of these is just a few millimeters in size and is located in the ear. It performs a variety of tasks in connection with the so-called stapedius muscle. As the smallest bone in humans, the stapes can be affected by diseases that lead to impaired hearing. An ENT doctor should therefore be consulted regularly. This article introduces the so-called stirrup and explains its importance as the smallest bone in humans.

The smallest bone in humans is in the ear

The smallest human bone is called the stirrup because of its shape and can quickly be found on many anatomy pictures. It is located in the inner ear anatomy and, together with the so-called hammer and anvil, is responsible for transmitting sound to the eardrum. The stirrup is only 3 mm large and therefore half the size of a grain of rice. Nevertheless, it is comparatively stable, so that fractures or similar damage to the smallest human bone rarely occur.

The stirrup has always been of great importance in human evolution. This is evident from the fact that it can also be found in amphibians, reptiles and birds. The connection to the so-called bony fish is particularly relevant in this context. The stirrup already forms in an embryo and has two so-called legs. This shape arises because the stapes develops around the so-called stapes artery, making it the distinctive smallest bone in humans.

Tasks as the smallest bone in humans

As the smallest human bone, the stirrup performs a variety of tasks. Its primary purpose is to pass on the vibrations that arrive in the inner ear to the eardrum. Without the stirrup, significantly less sound would reach us, meaning that human hearing would be significantly weaker.

When transmitting sound, the stapes, the smallest human bone, absorbs the vibrations from the medium of air and passes them on to the eardrum via the cochlea. There is a so-called liquid perilymph here, to which the sound is passed on. In this context, the stirrup ensures that the sound vibrations are amplified by a factor of 20 to 30. This is necessary because otherwise reflection losses would occur during the transition from air to liquid.

Another task of the smallest human bone is to protect the cochlea and the sensory cells within it. This ensures that sound transmission works properly over a long period of time. Because of this protective function, diseases of the stirrup are particularly dangerous and should be diagnosed and treated promptly.

Smallest human bone and the stapedius muscle

The smallest human bone, the stirrup, is connected to the so-called stapedius muscle. This is a muscle that leads directly to the stirrup. It is able to tense and loosen and thereby influence the mobility of the auditory ossicular chain. If there is a sudden, high sound pressure, the stapedius muscle tenses, causing the ossicular chain to stiffen.

The protective function for hearing can be traced back to this function and the interaction of the stirrup and muscle. This is to ensure that a sudden, high sound pressure does not cause damage to the ear. It is also possible to test the stabilus reflex using typanometry. The treating doctors therefore know exactly how reliably the muscle is working and how high its protective function still is. This allows them to draw conclusions about the tightness of the eardrum and make statements about the nerve connections in the brain stem and the nerves in the ear and face.

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Common diseases related to the smallest bone in humans

Diseases affecting the smallest bone in humans sometimes have massive effects on hearing as a whole. That's why those affected should react promptly to the first symptoms and seek help from a specialist. For example, so-called sclerotization of the membrane can occur. This means that the membrane ossifies and the transmission of sound waves is only possible to a limited extent. This means that the impulses no longer reach the eardrum with the desired strength, which affects hearing ability.

To date it is not yet clear what causes such ossification. It is assumed that middle ear infections or similar diseases lead to tympanic effusion, whereby fluid enters the middle ear anatomy and remains there. This can lead to inflammation, which in turn has a damaging effect on the smallest bones in humans.

It is pleasant that hearing loss caused by tympanic effusion is a reversible disease. For example, in some cases it is possible to improve hearing by removing the unwanted fluid or using an artificial stirrup. In order for this to be successful, the underlying disease must be precisely diagnosed.

Regular visits to the ENT doctor

In order to maintain and care for the best possible hearing for as long as possible, it is recommended to regularly visit an ENT doctor. This can check the functionality of your hearing and ensure that there are no unwanted illnesses or side effects. In this way, the stirrup, the smallest human bone, is optimally protected.

An ENT doctor should be consulted at the latest when the first symptoms appear. This makes it possible to identify the underlying diseases and, if necessary, combat them. This can be anything from a relatively harmless tympanic effusion to a tumor in the nasopharynx. The sooner clarity is provided here, the easier it is to prevent the stirrup, the smallest human bone, from suffering from diseases. If illnesses are present, it is advisable to seek help from specialized ENT doctors. They have great experience with the stirrup and have already carried out numerous operations in this area.

Conclusion: Smallest human bone - but oh-so!

Although the stirrup is the smallest human bone, it is quite inconspicuous, but it is of immense importance. It is only because of him that we are able to hear the way we do. Without the stirrup, sound transmission would be significantly weakened and one would be able to hear much less. It is therefore worthwhile to take care of the smallest bone in humans and to ensure that it remains healthy for a long time and can carry out its tasks in a targeted manner through preliminary examinations and appropriate therapies.

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