A healthy adult has around 200 bones. The smallest of these is just a few millimetres in size and is located in the ear. It fulfils a variety of tasks in connection with the so-called stapedius muscle. As the smallest bone in the human body, 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 stapes and explains what significance it has as the smallest bone in the human body.
The smallest bone in the human body is in the ear
The smallest bone in the human body is called the stirrup because of its shape and is found on many anatomical images quickly again. He is 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 in size and thus half the size of a grain of rice. Nevertheless, it is comparatively stable, so that fractures or similar damage to the smallest bone in the human body rarely occur.
The stapes has always been of great importance in the evolution of humans. This is shown by 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 stapes develops in embryos and has two so-called legs. This shape is created by the fact that the stapes develops around the so-called stapes artery and has thus become the unmistakable smallest bone in humans.
Functions as the smallest bone in the human body
As the smallest bone in the human body, the stirrup performs a variety of tasks. Its primary function is to transmit the vibrations that reach the inner ear to the eardrum. Without the stirrup, significantly less sound would reach us, meaning that human hearing would be significantly weaker.
When sound is transmitted, the stapes, the smallest bone in the human body, absorbs the vibrations from the air and passes them on to the eardrum via the cochlea. Here there is a so-called liquid perilymph, to which the sound is passed. In this context, the stapes ensures that the sound vibrations are amplified by a factor of 20 to 30. This is necessary because otherwise there would be reflection losses when the air passes to the liquid.
Another function of the smallest bone in the human body is to protect the cochlea and the sensory cells located therein. This ensures that sound transmission functions properly over a long period of time. Because of this protective function, diseases of the stapes are particularly dangerous and should be diagnosed and treated promptly.
Smallest bone in the human body and the stapedius muscle
The smallest bone in the human body, the stirrup, is connected to the so-called stapedius muscle. This is a muscle that leads directly to the stapes. It is able to contract and relax and thereby influence the mobility of the ossicular chain. If there is a sudden, high sound pressure, the stapedius muscle contracts, causing the ossicular chain to stiffen.
The protective function for the hearing is due to this function and the interaction between the stirrup and the muscle. This is to ensure that a sudden, high sound pressure does not cause damage to the ear. In addition, it is possible to test the Stabilus reflex using typanometry.The treating doctors therefore know exactly how reliably the muscle is working and how high the 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.
If you are interested in the anatomy of the ear, you will find a picture ENT collection, perfect for learning or exploring.
Common diseases related to the smallest bone in humans
Diseases of the smallest bone in the human body can have a massive impact on hearing as a whole. Therefore, those affected should react promptly at the first symptoms and seek help from a specialist. For example, a so-called sclerosis 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 impairs hearing.
To date, it is not yet clear what causes such ossification. It is assumed that middle ear infections or similar diseases lead to a middle ear effusion, causing fluid to enter the middle ear anatomy and remains there. This can lead to inflammation, which in turn has a damaging effect on the smallest bone in the human body.
The good news is that hearing loss caused by middle ear effusion is a reversible disease. For example, in some cases it is possible to improve hearing by removing the unwanted fluid or by using an artificial stirrup. However, in order for this to be successful, the underlying disease must be accurately diagnosed.
Regular visits to the ENT doctor
In order to mai