Structure, functions and diseases of the middle ear. Human ear anatomy Structure and functions of the middle ear

The ear is a complex organ of our body, located in the temporal part of the skull, symmetrically - left and right.

In humans, it consists of (the auricle and the auditory canal or canal), (the tympanic membrane and tiny bones that vibrate under the influence of sound at a certain frequency) and (which processes the received signal and transmits it to the brain using the auditory nerve).

Functions of the outdoor department

Although we all habitually believe that the ears are only an organ of hearing, in fact they are multifunctional.

In the process of evolution, the ears that we use now evolved from vestibular apparatus(organ of balance, whose task is to maintain the correct position of the body in space). plays this important role to this day.

What is the vestibular apparatus? Imagine an athlete who trains late at night, at dusk: running around his house. Suddenly he stumbled over a thin wire, imperceptible in the darkness.

What would happen if he didn't have a vestibular apparatus? He would have crashed, hitting his head on the asphalt. I might even die.

In fact, most healthy people in this situation throw their hands forward, bounce them, falling relatively painlessly. This happens due to the vestibular apparatus, without any participation of consciousness.

A person walking along a narrow pipe or a gymnastic beam also does not fall precisely thanks to this organ.

But the main role of the ear is the perception of sounds.

It matters to us, because with the help of sounds we orient ourselves in space. We walk along the road and hear what is happening behind us, we can step aside, giving way to a passing car.

We communicate with sounds. This is not the only channel of communication (there are also visual and tactile channels), but it is very important.

Organized, harmonized sounds we call "music" in a certain way. This art, like other arts, reveals to people who love it a huge world of human feelings, thoughts, relationships.

Our psychological state, our inner world depends on the sounds. The lapping of the sea or the noise of the trees are soothing, while technological noises annoy us.

Hearing characteristics

A person hears sounds in the range of approximately from 20 to 20 thousand hertz.

What is "hertz"? This is a unit of measure for the frequency of oscillation. What is the "frequency" here? Why is it used to measure the strength of sound?

When sounds enter our ears, the eardrum vibrates at a certain frequency.

These vibrations are transmitted to the bones (hammer, anvil and stirrup). The frequency of these oscillations serves as a unit of measurement.

What are "fluctuations"? Imagine girls swinging on a swing. If in a second they manage to rise and fall to the same point where they were a second ago, this will be one oscillation per second. Vibration of the tympanic membrane or the ossicles of the middle ear is the same thing.

20 hertz is 20 vibrations per second. This is very little. We hardly distinguish such a sound as a very low one.

What's happened "low" sound? Press the lowest key on the piano. A low sound will be heard. It is quiet, deaf, thick, long, hard to perceive.

We perceive a high sound as thin, piercing, short.

The range of frequencies perceived by a person is not at all large. Elephants hear extremely low-frequency sounds (from 1 Hz and above). Dolphins are much taller (ultrasounds). In general, most animals, including cats and dogs, hear sounds in a wider range than we do.

But this does not mean that they have better hearing.

The ability to analyze sounds and almost instantly draw conclusions from what is heard in humans is incomparably higher than in any animal.

Photo and diagram with description

The drawings with symbols show that a person is a bizarrely shaped cartilage covered with skin (the auricle). A lobe hangs below: this is a bag of skin filled with adipose tissue. Some people (one in ten) on the inside of the ear, on top, have a "Darwin's tubercle", a vestige left over from the time when the ears of human ancestors were sharp.

It can fit snugly to the head or protrude (protruding ears), be of different sizes. It does not affect hearing. Unlike animals, the external ear does not play a significant role in humans. We would hear about the same as we hear, even without it at all. Therefore, our ears are fixed or inactive, and the ear muscles in most members of the Homo sapiens species are atrophied, since we do not use them.

Inside the outer ear auditory canal, usually quite wide at the beginning (you can stick your little finger there), but tapering towards the end. This is also cartilage. The length of the auditory canal is from 2 to 3 cm.

- This is a system for transmitting sound vibrations, consisting of a tympanic membrane, which ends the auditory canal, and three small bones (these are the smallest parts of our skeleton): a hammer, anvil and stirrup.

Sounds, depending on their intensity, make eardrum vibrate at a certain frequency. These vibrations are transmitted to the hammer, which is connected to the eardrum with its “handle”. He hits the anvil, which transmits the vibration to the stirrup, the base of which is connected to the oval window of the inner ear.

- transmission mechanism. It does not perceive sounds, but only transmits them to the inner ear, at the same time significantly amplifying them (about 20 times).

The entire middle ear is only one square centimeter in the human temporal bone.

Designed for the perception of sound signals.

Behind the round and oval windows that separate the middle ear from the inner ear, there is a cochlea and small containers with lymph (this is such a liquid) located differently relative to each other.

Lymph perceives vibrations. Through the endings of the auditory nerve, the signal reaches our brain.


Here are all the parts of our ear:

• Auricle;
• auditory canal;
• eardrum;
• hammer;
• anvil;
• stirrup;
• oval and round windows;
• vestibule;
• cochlea and semicircular canals;
• auditory nerve.

Are there neighbors?

They are. But there are only three of them. This is the nasopharynx and the brain, as well as the skull.

The middle ear is connected to the nasopharynx by the Eustachian tube. Why is this needed? To balance the pressure on the eardrum from inside and outside. Otherwise, it will be very vulnerable and can be damaged and even torn.

In the temporal bone of the skull and just located. Therefore, sounds can also be transmitted through the bones of the skull, this effect is sometimes very pronounced, because of which such a person hears the movement of his eyeballs, and perceives his own voice distorted.

With the help of the auditory nerve, the inner ear is connected to the auditory analyzers of the brain. They are located in the upper lateral part of both hemispheres. In the left hemisphere - the analyzer responsible for the right ear, and vice versa: in the right - responsible for the left. Their work is not directly connected with each other, but is coordinated through other parts of the brain. That is why it is possible to hear with one ear while closing the other, and this is often sufficient.

Useful video

Familiarize yourself visually with the diagram of the structure of the human ear with the description below:

Conclusion

In human life, hearing does not play the same role as in the life of animals. This is due to many of our special abilities and needs.

We can not boast of the most acute hearing in terms of its simple physical characteristics.

However, many dog ​​owners have noticed that their pet, although it hears more than the owner, reacts more slowly and worse. This is explained by the fact that the sound information entering our brain is analyzed much better and faster. We have better predictive abilities: we understand what sound means what, what can follow it.

Through sounds, we are able to convey not only information, but also emotions, feelings, and complex relationships, impressions, images. Animals are deprived of all this.

People do not have the most perfect ears, but the most developed souls. However, very often the way to our souls lies through our ears.

A person receives most of the information about the world around him through sight and hearing. Moreover, the structure of the ear is very complex. Any violation in the middle ear or other parts of the hearing aid can lead not only to hearing loss, but also to the creation of a situation where a person's life is in danger. Let's figure out what are the functions and structure of the middle ear, what diseases affect this part of the hearing aid and how to prevent their occurrence.

The middle ear is located between the inner and outer. The main purpose of this part of the hearing aid is to conduct sounds. The middle ear consists of the following parts:

1. Auditory ossicles. They are stirrup, hammer and anvil. It is these details that help to transmit sounds, and distinguish them by strength and height. The peculiarities of the work of the auditory ossicles help to protect the hearing aid from sharp and loud sounds.
2. auditory tube. This is the passage that connects the nasopharynx with the tympanic cavity. Its mouth is closed when a person swallows or sucks something. In newly born children, for some time the auditory tube is wider and shorter than in adulthood.
3. drum cavity. It is this part of the middle ear that contains the auditory ossicles described above. The location of the tympanic cavity is the area between the outer ear and the temporal bone.
4. Mastoid. This is the convex part of the temporal bone. It contains cavities that are filled with air and communicate with each other through narrow holes.

The middle ear is an apparatus that conducts sound vibrations, consisting of air cavities and complex anatomical structures. The tympanic cavity is lined with mucous membrane and separated from the rest of the skull by the upper wall. All auditory ossicles are also covered with mucous. The middle and inner ear are separated by a bony wall. They are connected by only two holes:

• round window;
• oval window in the ear.

Each of them is protected by a flexible and elastic membrane. The stirrup, one of the auditory ossicles, enters the oval window in front of the water-filled inner ear.

Important! Also in the work of this part of the hearing aid, a huge role is assigned to the muscles. There is a muscle that controls the eardrum and a group of muscles that controls the auditory ossicles.

Middle ear functions

Air cavities and other anatomical structures located in the middle ear provide sound permeability. The main functions of the middle ear are:

• maintaining the health of the eardrum;
• transmission of sound vibrations;
• protection of the inner ear from harsh and too loud sounds;
• ensuring the susceptibility of sounds of various strengths, heights and loudness.

Important! The main function of the middle ear is to conduct sounds. And any disease or injury that affects this part of the hearing aid can lead to permanent total or partial hearing loss.

Diseases of the middle ear

The main symptoms of the occurrence of problems in the middle ear, experts call the following signs and conditions of a person:

• pain in the ear area of ​​varying intensity (mostly very strong);
• feeling of congestion;
• reduction or complete loss of hearing;
• discharge of fluid or pus from the ear canal;
• increased body temperature;
• decreased appetite and poor sleep;
• change in the color of the eardrum to more red.

Among the most common diseases of the middle ear, it is worth noting the following:

1. Purulent otitis media. This is inflammation, in which purulent and purulent-bloody discharge from the ear canal is observed, a person complains of unbearable pain, and hearing is significantly impaired. The disease affects the middle ear cavity and the tympanic membrane, and can spread to other parts of the hearing aid.
2. Cicatricial otitis. In this case, the inflammatory process led to the formation of scars and a decrease in the mobility of the auditory ossicles. Because of this, there is a strong hearing loss.
3. Mesotympanitis. The disease is similar in symptoms to purulent otitis media. In this case, the eardrum is affected, and the person notes hearing loss and purulent discharge.
4. Epidemic. In the course of this disease, inflammation of the epitympanic space of the middle ear occurs, a prolonged course of the inflammatory process can disrupt the structure of the middle and inner ear, which will lead to a decrease and a sharp deterioration in hearing.
5. Mastoiditis. Most often, this is a consequence of purulent otitis media not treated correctly and in a timely manner, which affects not only the middle ear, but also the mastoid process.
6. Middle ear catarrh. The disease usually precedes purulent otitis and affects the auditory tube.
7. Bullous otitis. The disease occurs against the background of the flu and has symptoms similar to other otitis media. The focus of the inflammatory process is located in the epitympanic air cavity.

Important! Often problems with the middle ear can occur against the background of various diseases of an infectious nature, for example, tonsillitis, sinusitis, rhinitis, laryngitis, influenza. Also, improper care of the ears and nose, injuries, water entering the ear canal, hypothermia and drafts are also common causes.

Prevention of diseases of the middle ear

Wear a hat in winter

As a preventive measure for the development of diseases of the middle ear, experts recommend that children and adults adhere to the following rules:

1. Timely treat diseases of the upper respiratory tract, nose and ears. Infection with improperly selected treatment or its absence quickly spreads from the nasopharynx or outer ear further than it disrupts the functioning of the hearing aid. Always follow the recommendations of doctors during the treatment of diseases of the ENT organs. Do not stop therapy, even if you feel great, do not change the dosage and regimen of drugs, do not prolong the period of their use.
2. If a person has congenital anomalies in the structure of the ear, then they should be solved with the help of a specialist, if possible. Sometimes it is necessary to perform an operation, and in some cases it is enough to take certain medications.
3. Hygiene. The accumulation of wax, dirt or water in the ear canal can lead to inflammation. Therefore, try to clean your ears and your children in a timely manner with cotton turundas. When swimming or bathing, use special caps and earplugs, avoid getting a direct stream of water into the ear canal.
4. Make sure your ears are not injured. The ingress of a foreign body, the use of sharp and hard objects when cleaning the ears, as well as some other reasons, can cause inflammation and provoke infection in the middle ear.
5. Wear a hat in winter. Protect yourself from drafts and hypothermia, sudden changes in temperature and humidity. For small children, it is best to wear special thin caps, even if the room temperature is comfortable.
6. In childhood, as a preventive measure for frequently occurring otitis media and other inflammatory processes due to overgrown or greatly enlarged adenoids, their removal is sometimes recommended.

Important! The best prevention of diseases of the middle ear is to strengthen the immune system. A balanced diet, moderate physical activity, hardening - all this will increase the body's endurance and resistance to infections and significantly reduce the risk of developing diseases.

Remember, diseases of the middle ear are very dangerous for hearing and human life. In case of any disturbing symptoms, you should immediately consult a doctor. It is impossible to self-medicate with otitis media and other inflammatory processes either in childhood or in adulthood. This can lead to serious complications, including the spread of the infection beyond the middle ear, its penetration into the brain, as well as reduction and complete loss of hearing. The sooner you see a doctor and start treatment, the lower the risk of complications and the higher the chance to eliminate the disease as soon as possible without any consequences.

Like many other organs, they are characterized by a very complex structure and functions. In particular, the middle ear, as one of the components of the hearing organ, is a very important link in the auditory process, since it is responsible for the sound-conducting function.

As already mentioned, human ear- This is the most complex hearing aid, which consists of 3 departments:

Each of the above departments performs a specific job and has its own special characteristics.

The anatomical structure of the organ of hearing

To say that some part of the ear is the main one, and the rest are secondary, is fundamentally wrong. After all, if one of the components of the organ is violated, a person may experience hearing impairment, or even its loss.

Interesting. When a person needs to hear something, he “puts out” the right ear closer and for good reason. Scientists have proven that the hearing acuity of the right ear is slightly higher than the left.

Middle ear is an element of the human auditory system. It looks like a very small space, which is located between the other two parts of the hearing analyzer: external and internal. It consists of 3 cavities connected to each other.

So, having briefly familiarized ourselves with the structure of the ear and having determined what its middle section is, then we will consider what is located in the middle part of the ear.

The structure of the middle ear

In terms of structural complexity, the middle section is second only to the inner part of the ear. The composition of the middle ear includes the following components:

1. drum cavity.
2. System of cavities of the mastoid process.

Detailed anatomical structure of the middle part of the organ of hearing

tympanic cavity is an important part of this section. It contains the auditory ossicles: hammer, anvil, stirrup. Their names come from the originality of their structure and functioning. The system of mutual work of these bones is similar to the mechanism of levers.

All 3 auditory ossicles are connected to each other. The tiny handle of the malleus is located in the center of the eardrum, and its head is connected to the incus. She, in turn, is connected to the stirrup. The latter through the oval window is connected to the inner ear.

Reference. Such a device of the bones causes not only the transmission, but also the amplification of sound. Approximately it amplifies in 60-70 times.

The surface of the stirrup is much smaller than the tympanic membrane, which means that its impact on the oval window is many times stronger. Thanks to this, a person can hear very quiet sounds.

Mastoid cavity system located in the temporal bone and filled with air. The largest cavity is the mastoid cave, which is connected to the tympanic cavity with the help of a special channel. All cells are interconnected by narrow passages, which improves the sound characteristics of the sound-conducting section.

Location of the mastoid air cavity system

Eustachian tube- an important component of the middle part. It acts as a link between the tympanic cavity and the nasopharynx. The opening of the Eustachian tube is located on the side wall of the pharynx flush with the hard palate. Inside, it is lined with ciliated epithelium, which protects the middle ear from pathogenic agents entering it.

The anatomy of this department provides for the presence of muscle fibers. In this situation, there are only two of them - the stirrup muscle and the muscle that strains the eardrum. They are responsible for the function of maintaining the auditory ossicles in weight and their regulation.

Reference. The ear muscles are the smallest muscles in the human body.

Where is the middle ear

Location in the skull of the temporal bone, which houses the middle ear

The middle part of the ear is located in the thickness of the temporal bone. It is a paired bone, characterized by the most complex anatomy, since it is responsible for all 3 functions of the skeleton. So, it creates part of the side wall and the base of the skull, and also contains the organ of hearing and balance.

As for location in the auditory analyzer system, then this part of the organ begins immediately behind the eardrum, to which the ear canal leads. It acts as a partition between the outer and middle sections.

And the inner ear is separated by a bone wall, in which there are 2 windows: oval and round, protected by a special membrane.

What is the middle ear cavity filled with?

The Eustachian tube equalizes the pressure in the middle ear, otherwise we constantly felt stuffy in our ears

Most people who are interested ask themselves the question: “What is the cavity of the human middle ear filled with?” It would seem a very simple question, the answer to which comes by itself, if you only think logically.

But no, for some reason this issue generates a lot of controversy on the forums. And all because some people ardently dispute, believing that the middle ear is filled with some kind of liquid. We won’t even give names here, because there are a huge number of options. And all the unbelievers!

So what is the middle ear filled with? By air! The middle section of the ear cavity is a kind of air chamber.

As mentioned earlier, the middle ear is connected to the nasopharynx through the Eustachian tube. However, it not only connects these two cavities, but also with the help of it, the pressure in the middle ear equalizes with atmospheric pressure.

If there were no such device and air communication, then we would constantly feel a feeling of congestion in the ears.

Functions of the middle ear

The most important duty, the implementation of which is assigned to this part of the organ of hearing, is the conduction of sound waves. So, they make the eardrum vibrate, which in turn transmits vibrations to the auditory ossicles. Next, the sound vibrations are transmitted to the inner part of the ear, where they are converted into an impulse and sent to the brain.

The main function of the middle ear is sound conduction

The anatomical structure of this part of the ear cavity provides it with the following functions:

• ensuring the tone of the components of the middle section;
• protection against loud sounds;
• adaptation of the organ to a variety of sounds.

Important. However, such protection is powerless against sudden deafening sounds. For example, an explosion can damage an acoustic device because the muscle contractions in the middle ear are a little late. It takes about 10ms to respond.

Also, the middle ear is a “protector”, since it protects the vulnerable inner ear from such phenomena:

1. Dust and moisture.
2. mechanical influences.
3. The penetration of pathogenic organisms.
4. Jumps in atmospheric pressure.

Based on the structure and function of the middle ear, it is possible to say that without it, a person would not be familiar with the auditory function. Each of its components has its own specific role, which makes it possible to ensure the normal functioning of the hearing organ as a whole.

However, it is worth remembering that the normal functioning of this organ also depends on careful attitude and timely treatment, in the event of certain pathologies. Such actions are an opportunity to preserve the acuity of hearing until old age.

The middle ear consists of cavities and canals that communicate with each other: the tympanic cavity, the auditory (Eustachian) tube, the passage to the antrum, the antrum and the cells of the mastoid process (Fig.). The boundary between the outer and middle ear is the tympanic membrane (see).

Rice. 1. Lateral wall of the tympanic cavity. Rice. 2. Medial wall of the tympanic cavity. Rice. 3. A cut of the head, carried out along the axis of the auditory tube (lower part of the cut): 1 - ostium tympanicum tubae audltivae; 2 - tegmen tympani; 3 - membrana tympani; 4 - manubrium mallei; 5 - recessus epitympanicus; 6 -caput mallei; 7-incus; 8 - cellulae mastoldeae; 9 - chorda tympani; 10-n. facialis; 11-a. carotis int.; 12 - canalis caroticus; 13 - tuba auditiva (pars ossea); 14 - prominentia canalis semicircularis lat.; 15 - prominentia canalis facialis; 16-a. petrosus major; 17 - m. tensor tympani; 18 - promontory; 19 - plexus tympanicus; 20 - steps; 21-fossula fenestrae cochleae; 22 - eminentia pyramidalis; 23 - sinus sigmoides; 24 - cavum tympani; 25 - entrance to meatus acustlcus ext.; 26 - auricula; 27 - meatus acustlcus ext.; 28-a. et v. temporales superficiales; 29 - glandula parotis; 30 - articulatio temporomandibularis; 31 - ostium pharyngeum tubae auditivae; 32 - pharynx; 33 - cartilago tubae auditivae; 34 - pars cartilaginea tubae auditivae; 35-n. mandibularis; 36-a. meningea media; 37 - m. pterygoideus lat.; 38-in. temporalis.

The middle ear consists of the tympanic cavity, the Eustachian tube, and the mastoid air cells.

Between the outer and inner ear is the tympanic cavity. Its volume is about 2 cm 3. It is lined with a mucous membrane, filled with air and contains a number of important elements. There are three auditory ossicles inside the tympanic cavity: the malleus, anvil, and stirrup, so named for their resemblance to the indicated objects (Fig. 3). The auditory ossicles are interconnected by movable joints. The hammer is the beginning of this chain, it is woven into the eardrum. The anvil occupies a middle position and is located between the malleus and the stirrup. The stirrup is the last link in the ossicular chain. There are two windows on the inside of the tympanic cavity: one is round, leading to the cochlea, covered with a secondary membrane (unlike the already described tympanic membrane), the other is oval, into which a stirrup is inserted, like in a frame. The average weight of the malleus is 30 mg, the incus is 27 mg, and the stirrup is 2.5 mg. The malleus has a head, a neck, a short process and a handle. The handle of the malleus is woven into the eardrum. The head of the malleus is connected to the incus at the joint. Both of these bones are suspended by ligaments to the walls of the tympanic cavity and can move in response to vibrations of the tympanic membrane. When examining the tympanic membrane, a short process and the handle of the malleus are visible through it.

Rice. 3. Auditory ossicles.

1 - anvil body; 2 - a short process of the anvil; 3 - a long process of the anvil; 4 - rear leg of the stirrup; 5 - foot plate of the stirrup; 6 - hammer handle; 7 - anterior process; 8 - neck of the malleus; 9 - head of the malleus; 10 - hammer-incus joint.

The anvil has a body, short and long processes. With the help of the latter, it is connected with the stirrup. The stirrup has a head, a neck, two legs and a main plate. The handle of the malleus is woven into the tympanic membrane, and the foot plate of the stirrup is inserted into the oval window, which forms the chain of auditory ossicles. Sound vibrations propagate from the eardrum to the chain of auditory ossicles that form a lever mechanism.

Six walls are distinguished in the tympanic cavity; The outer wall of the tympanic cavity is mainly the tympanic membrane. But since the tympanic cavity extends upwards and downwards beyond the tympanic membrane, in addition to the tympanic membrane, bone elements also participate in the formation of its outer wall.

The upper wall - the roof of the tympanic cavity (tegmen tympani) - separates the middle ear from the cranial cavity (middle cranial fossa) and is a thin bone plate. The lower wall, or floor of the tympanic cavity, is located slightly below the edge of the tympanic membrane. Below it is the bulb of the jugular vein (bulbus venae jugularis).

The posterior wall borders on the air system of the mastoid process (antrum and cells of the mastoid process). In the posterior wall of the tympanic cavity, the descending part of the facial nerve passes, from which the ear string (chorda tympani) departs here.

The anterior wall in its upper part is occupied by the mouth of the Eustachian tube connecting the tympanic cavity with the nasopharynx (see Fig. 1). The lower section of this wall is a thin bone plate that separates the tympanic cavity from the ascending segment of the internal carotid artery.

The inner wall of the tympanic cavity simultaneously forms the outer wall of the inner ear. Between the oval and round window, it has a protrusion - a cape (promontorium), corresponding to the main curl of the snail. On this wall of the tympanic cavity above the oval window there are two elevations: one corresponds to the canal of the facial nerve passing directly above the oval window, and the second corresponds to the protrusion of the horizontal semicircular canal, which lies above the canal of the facial nerve.

There are two muscles in the tympanic cavity: the stapedius muscle and the muscle that stretches the eardrum. The first is attached to the head of the stirrup and is innervated by the facial nerve, the second is attached to the handle of the malleus and is innervated by a branch of the trigeminal nerve.

The Eustachian tube connects the tympanic cavity with the nasopharyngeal cavity. In the unified International Anatomical Nomenclature, approved in 1960 at the VII International Congress of Anatomists, the name "Eustachian tube" was replaced by the term "auditory tube" (tuba anditiva). The Eustachian tube is divided into bony and cartilaginous parts. It is covered with a mucous membrane lined with ciliated cylindrical epithelium. Cilia of the epithelium move towards the nasopharynx. The length of the tube is about 3.5 cm. In children, the tube is shorter and wider than in adults. In a calm state, the tube is closed, since its walls in the narrowest place (at the transition point of the bone part of the tube into the cartilage) are adjacent to each other. When swallowing, the tube opens and air enters the tympanic cavity.

The mastoid process of the temporal bone is located behind the auricle and external auditory canal.

The outer surface of the mastoid process consists of compact bone tissue and ends at the bottom with an apex. The mastoid process consists of a large number of air (pneumatic) cells separated from each other by bony septa. Often there are mastoid processes, the so-called diploetic, when they are based on spongy bone, and the number of air cells is insignificant. In some people, especially those suffering from chronic purulent disease of the middle ear, the mastoid process consists of dense bone and does not contain air cells. These are the so-called sclerotic mastoid processes.

The central part of the mastoid process is a cave - antrum. It is a large air cell that communicates with the tympanic cavity and with other air cells of the mastoid process. The upper wall, or roof of the cave, separates it from the middle cranial fossa. In newborns, the mastoid process is absent (not yet developed). It usually develops in the 2nd year of life. However, the antrum is also present in newborns; it is located in them above the auditory canal, very superficially (at a depth of 2-4 mm) and subsequently shifts backwards and downwards.

The upper border of the mastoid process is the temporal line - a protrusion in the form of a roller, which is, as it were, a continuation of the zygomatic process. At the level of this line, in most cases, the bottom of the middle cranial fossa is located. On the inner surface of the mastoid process, which faces the posterior cranial fossa, there is a grooved depression in which the sigmoid sinus is placed, which drains venous blood from the brain into the bulb of the jugular vein.

The middle ear is supplied with arterial blood mainly from the external and to a lesser extent from the internal carotid arteries. The innervation of the middle ear is carried out by branches of the glossopharyngeal, facial and sympathetic nerves.

Middle ear - the smallest his department is in capacity but not in importance. In the auditory process, he is assigned a sound-conducting role.

The middle ear, located deep in the temporal bone, is a complex of air cavities with a total volume of only 75 ml, miniature bones, muscles and ligaments. Its central part is tympanic cavity- located between the tympanic membrane and, it has a mucous membrane and the shape resembles a prism.

Another element of this part of the hearing aid is auditory (eustachian) tube. Its mouth through the hard palate has access to the nasopharynx. But more often it is closed, only with sucking or swallowing movements does the entrance open slightly. In infants, this organ is not yet fully developed - their tube is wider and shorter than in adults, so it is easier to get a viral infection through it.

In addition, the bony auditory canal and mastoid process have not yet formed in infants. And the membrane is connected to the temporary bone groove and the lower part of the temporal bone. By the age of three, these features of the anatomy of the ear are aligned.

The third element of this part of the organ of hearing is mastoid. This is the back of the temporal bone, which has air cavities. Connecting with each other by narrow passages, they improve auditory acoustics.

Compound

List of components middle ear:

1. Eardrum.
2. drum cavity. It is bounded by six walls, including the tympanic membrane. A string of the same name passes through it.
3. Auditory ossicles: stirrup, anvil and malleus.
4. Two muscles - tympanic and stirrup.
5. Mastoid, air cells.
6. Auditory or Eustachian tube.

Description of internal parts, their function and location

The structure of a small part of the human auditory apparatus - the middle ear - deserves a detailed description due to its importance:

Liaison with other authorities

The middle ear is located between and its department. Some of its parts are directly connected with other parts of the body:

The middle ear has a complex structure and includes several important functional elements. Associated in a single complex, they provide sound transmission, have access to many body systems. Without this small element, it would be impossible to hear and distinguish sounds of different heights and strengths.

Useful video

Check out the diagram of the structure of the human middle ear below: