It is transmitted with the help of air vibrations that all moving or trembling objects produce, and the human ear is an organ designed to capture these vibrations (vibrations). The structure of the human ear provides a solution to this difficult task.

The human ear has three sections: the outer ear, middle ear and inner ear. Each of them has its own structure, and together they form a kind of long tube that goes deep into the human head.

The structure of the human outer ear

The outer ear begins with the auricle. It is the only part of the human ear that is outside the head. The auricle is funnel-shaped, which captures sound waves and redirects them to the ear canal (it is located inside the head, but is also considered part of the outer ear).

The inner end of the auditory canal is closed by a thin and elastic septum - the tympanic membrane, which takes on the vibrations of the sound waves that have passed through the auditory canal, begins to tremble and transmits them further to the middle ear and, in addition, separates the middle ear from the air. Let's see how this happens.

The structure of the human middle ear

The middle ear is made up of three ear ossicles called the malleus, anvil, and stirrup. All of them are connected to each other by small joints.

The hammer adjoins the eardrum from the inside of the head, takes on its vibrations, makes the anvil tremble, and that, in turn, the stirrup. The stirrup vibrates already much stronger than the eardrum and transmits such amplified sound vibrations to the inner ear.

The structure of the human inner ear

The inner ear is used to perceive sounds. It is firmly attached to the bones of the skull, almost completely covered by a bone case with a hole to which the stirrup adjoins.

auditory part inner ear- This is a spiral-shaped bone tube (cochlea), having a length of about 3 centimeters and a width of less than a centimeter. From the inside, the cochlea of ​​the inner ear is filled with fluid, and its walls are covered with very sensitive hair cells.

Knowing the structure of the human inner ear, it is very easy to understand how it works. The stirrup adjoining the hole in the wall of the cochlea transmits its vibrations to the fluid inside it. Fluid trembling is perceived by hair cells, which, with the help of auditory nerves, transmit signals about it to the brain. And already the brain, its auditory zone, processes these signals, and we hear sounds.

In addition to the ability to hear, the structure of the human ear also provides its ability to maintain balance. Special - semicircular canals - is placed in the inner ear.

The ear consists of three sections: outer, middle and inner. The outer and middle ear conduct sound vibrations to the inner ear and are the sound-conducting apparatus. The inner ear forms the organ of hearing and balance.

outer ear It consists of the auricle, external auditory canal and tympanic membrane, which are designed to capture and conduct sound vibrations to the middle ear.

Auricle consists of elastic cartilage covered with skin. Cartilage is absent only in the earlobe. The free edge of the shell is wrapped, and is called a whorl, and the antihelix is ​​located parallel to it. At the front edge of the auricle, a protrusion is distinguished - a tragus, and behind it is an antitragus.

External auditory canal is a short S-shaped canal 35-36 mm long. It consists of a cartilaginous part (1/3 of the length) and bone (the remaining 2/3 of the length). The cartilaginous part passes into the bone at an angle. Therefore, when examining the ear canal, it must be straightened.

The external auditory meatus is lined with skin containing sebaceous and sulfuric glands that secrete sulfur. The passage ends at the tympanic membrane.

eardrum - it is a thin translucent oval plate, which is located on the border of the outer and middle ear. It stands obliquely with respect to the axis of the external auditory canal. Outside, the eardrum is covered with skin, and inside is lined with a mucous membrane.

Middle ear includes the tympanic cavity and the auditory (Eustachian) tube.

tympanic cavity located in the thickness of the pyramid of the temporal bone and is a small space of a cuboid shape, with a volume of about 1 cm 3.

From the inside, the tympanic cavity is lined with a mucous membrane and filled with air. It contains 3 auditory ossicles; hammer, anvil and stirrup, ligaments and muscles. All bones are interconnected through a joint and covered with a mucous membrane.

The hammer with its handle is fused with the eardrum, and the head is connected to the anvil, which in turn is movably connected to the stirrup.

The function of the ossicles is to transmit sound waves from the eardrum to the inner ear.

The tympanic cavity has 6 walls:

1. Upper the tire wall separates the tympanic cavity from the cranial cavity;

2. Lower the jugular wall separates the cavity from the outer base of the skull;

3. Anterior carotid separates the cavity from the carotid canal;

4. Posterior mastoid wall separates the tympanic cavity from the mastoid process

5. Lateral wall is the tympanic membrane itself

6. medial wall separates the middle ear from the inner ear. It has 2 holes:

- oval- the window of the vestibule, covered with a stirrup.

- round- window of the cochlea, covered by the secondary tympanic membrane.

tympanic cavity with auditory tube communicates with the nasopharynx.

auditory trumpet- This is a narrow channel about 35 mm long, 2 mm wide. Consists of cartilaginous and bone parts.

The auditory tube is lined with ciliated epithelium. It serves to supply air from the pharynx into the tympanic cavity and maintains the same pressure in the cavity as the external one, which is very important for the normal operation of the sound-conducting apparatus. Through the auditory tube, an infection can pass from the nasal cavity to the middle ear.

Inflammation of the auditory tube is called eustachitis.

inner ear located in the thickness of the pyramid of the temporal bone and separated from the tympanic cavity by its medial wall. It consists of a bony labyrinth and a membranous labyrinth inserted into it.

Bone labyrinth is a system of cavities and consists of 3 departments: vestibule, cochlea and semicircular canals.

threshold- This is a cavity of small size and irregular shape, occupying a central position. It communicates with the tympanic cavity through an oval and round opening. In addition, there are 5 small holes in the vestibule, through which it communicates with the cochlea and semicircular canals.

Snail is a convoluted spiral canal that forms 2.5 turns around the axis of the cochlea and ends blindly. The axis of the cochlea lies horizontally and is called the bony shaft of the cochlea. A bone spiral plate is wrapped around the rod.

Semicircular canals- represented by 3 arcuate tubes lying in three mutually perpendicular planes: sagittal, frontal, horizontal.

membranous labyrinth - located inside the bone, resembles it in shape, but has a smaller size. The wall of the membranous labyrinth consists of a thin connective tissue plate covered with squamous epithelium. Between the bony and membranous labyrinth there is a space filled with liquid - perilymph. The membranous labyrinth itself is filled endolymph and is a closed system of cavities and channels.

In the membranous labyrinth, the elliptical and spherical sacs, three semicircular ducts and the cochlear duct are isolated.

Elliptical pouch communicates with the semicircular duct through five openings but spherical- with cochlear duct.

On the inner surface spherical and elliptical pouches(uterus) and semicircular ducts there are hair (sensitive) cells covered with a jelly-like substance. These cells perceive endolymph vibrations during movements, turns, tilts of the head. The irritation of these cells is transmitted to the vestibular part of the VIII pair of cranial nerves, and then to the nuclei medulla oblongata and cerebellum, then to the cortical region, i.e. in the temporal lobe of the brain.

On a surface sensitive cells there is a large number of crystalline formations consisting of calcium carbonate (Ca). These formations are called otoliths. They are involved in the excitation of hair sensitive cells. When the position of the head changes, the pressure of the otoliths on the receptor cells changes, which causes their excitation. Hair sensory cells (vestibuloreceptors), spherical, elliptical sacs (or uterus) and three semicircular ducts make up vestibular (otolithic) apparatus.

cochlear duct has a triangular shape and is formed by the vestibular and main (basilar) membrane.

On the walls of the cochlear duct, namely on the basilar membrane, there are receptor hair cells (auditory cells with cilia), the vibrations of which are transmitted to the cochlear part of the VIII pair of cranial nerves, and then along this nerve the impulses reach the auditory center located in the temporal lobe.

In addition to hair cells, on the walls of the cochlear duct there are sensory (receptor) and supporting (supporting) cells that perceive perilymph vibrations. Cells located on the wall of the cochlear duct form the auditory spiral organ (the organ of Corti).

With the help of hearing, a person can pick up and perceive sound vibrations. The structure of the ear is very complex, but it is thanks to this organ that people can determine where the sound is coming from, and, accordingly, where the sound source is located. Without the ear, it is impossible to carry out speech and sound communication between people. In addition, hearing plays an important role in the formation of speech and mental development. So, let's try to analyze in more detail how the human ear is arranged, what it is, why it has such a complex device and what are its main functions and purpose.

For information

The anatomical structure of the ear and its main parts has a huge impact on the quality of hearing. The speech of a person directly depends on how well this organ is arranged. Accordingly, the healthier the ear, the easier it is for us to talk, pick up sounds and, in general, live. It is these features that prove to us that the correct arrangement of the ear is of great importance.

It is necessary to start examining the auditory organ from the auricle, since it is she who first of all catches the eye. Even a small child knows what the ear looks like and what function it performs. Thanks to the outer part of the organ, it is possible to optimize the sounds that come to us. Do not exclude the fact that it is the auricle that is of great cosmetic importance.

The ear provides two main tasks: it picks up sound impulses and helps to maintain a person in a certain state. This organ is responsible for balance.. It is located in the temporal region of the skull. Outside it is presented in the form of auricles. A person can perceive various sounds with a frequency of approximately 16 to 20 thousand vibrations per 1 second. The auditory analyzer helps us with this. It includes several components:

• peripheral part
• The conductive part lies in the auditory nerve and the central section
• Central part - represents the auditory zone, located in the temporal lobe of the cerebral cortex

The device of the ear can be divided into 3 areas:

• outer ear
• Middle ear
• inner ear

Each of these sections has its own structure. Connecting together, they create a kind of long labyrinth, which is directed deep into the head. Let's take a closer look at each of these sections.

outer ear

The outer passage is a natural extension of the inner cavity. In an adult, its length is approximately 2.5 cm. During life, its diameter may vary. The shape of the auricle is rounded. The outer part consists of cartilage, and the inner region of bone. I would also like to note the fact that most, approximately 2/3, is occupied by cartilage tissue, and everything else belongs to bone. For those who are particularly interested in this topic, I would like to remind you that bone tissue is connected to cartilage thanks to fibrous tissue.

The outer ear represents the auricle and the external auditory canal. Appearance shell is a fairly flexible cartilage, which is covered epithelial tissue. IN lower section earlobe is located. This skin fold consists mainly of adipose tissue and epithelium. It is the outer ear that is very susceptible to various injuries and damage. That is why, for example, in wrestling athletes, this area is often deformed.

The cartilaginous tissue of the auricle has a thickness of about 1 mm, it is additionally covered with a layer of perichondrium and skin. The lobe has no cartilaginous tissue. The shell itself is concave, and along its edge there is a curl, but in the inner part there is an antihelix. They are separated from each other by a small depression, which is called a boat. This is followed by a cavity that appears to be more recessed. In front of her is a tragus.

The system is quite complex. Initially, the sound is reflected from the folds of the ear shell and is directed directly into the ear canal. Its length is 30 mm. In the initial part, it is represented by cartilage, in its shape it resembles a gutter. It is in this department that small gaps are located, which closely border on the salivary gland.

Gradually, the cartilaginous section switches to the bone, which is slightly curved. In order to examine it from the inside, specialists slightly pull the ear back and then up. Inside the ear canal is covered with sulfur and sebaceous glands. It is they who produce the so-called earwax. This sticky substance is here for a reason, it performs an important task. It is sulfur that can trap dust and prevent various microorganisms from entering the internal auditory canal. Gradually the sulfur is removed. As a rule, this happens during chewing, when the walls of the passage fluctuate.

The auditory meatus ends with the tympanic membrane, which is peculiar and closes it. This area closely borders the salivary gland, lower jaw and facial nerve. It is the tympanic membrane that is the main line between the outer and middle ear. The auricle captures certain sounds, which, in turn, hit the eardrum, which creates vibrations. That is why the soldiers were advised to keep their mouths closed as much as possible in order not to injure their eardrums during the explosion.

As you can see, the structure and functions of the ear are not as simple as they might seem. The outer organ ends with the eardrum. It is a partially transparent oval plate. Its thickness is about 0.1 mm, its width is 9 mm, and its size is about 1 cm. This plane, in relation to the ear canal, is located at a slight inclination and is slightly extended into the inner part. The middle ear follows the eardrum. The most important task of the outer ear is to capture sound vibrations and transmit them to the middle ear.

The eardrum is virtually indestructible. In addition to broadcasting sound vibrations, it also performs another task - it protects the ear from the penetration of dangerous microorganisms, various substances and foreign small objects into the auditory organ.

Due to its strong structure, the eardrum can withstand intense pressure, which is significantly greater than atmospheric pressure. It has the following structure:

• Epithelial cells, which are a kind of duration of the integument of the ear
• fibrous fibers
• mucous membrane

The tympanic membrane has such high strength due to the fibrous fibers that are closely intertwined. The elastic properties of the membrane are due to the constantly maintained temperature and humidity. The structure of the ear canal allows you to create a certain environment for the formation of a reliable membrane. In addition, these indicators remain the same even with changes in weather conditions. Whether you're indoors or walking through a snow-covered city, the inside of your ear is always kept at the same temperature.

On the outer part of the membrane there is a small depression that follows towards the inner ear. This area is called the umbilicus. It is located slightly below the central part of the membrane.

Most of this membrane is securely attached to the bony groove, due to which it has a tight tension. The rest of the membrane has a looser position, and it also has only 2 layers (there is no connecting layer).

On the reverse side, the tympanic membrane closely adjoins the tympanic cavity. In an adult, it has a slight bias towards the inner ear. In newborns, this slope is much greater, while in the embryo the tympanic membrane is located almost horizontally.

The functional characteristics of the tympanic membrane are determined by its location and structure. They consist not only in the conduction of sounds, but also in the protection of the inner ear from various influences. The structure of the human ear is perfect and stunning in its genius. The ear canal has its own vibrations. If the sound received from the outside is combined with these vibrations, then the eardrum is very strong pressure. That is why we perceive certain sounds as unpleasant.

The outer ear is a complex device and can greatly amplify sound at the eardrum. The diameter of the passage gradually changes. With age, the flexibility of the eardrum is lost, respectively, the person begins to hear worse. However, it is possible to receive sounds without using the eardrum. In this case, sound can be transmitted through the bones of the skull directly into the cochlea. If the integrity of the middle fibers of the tympanic membrane is violated, it is no longer possible to restore them. Because of this, the main function of the ear is impaired, which can lead to partial or complete hearing loss.

How is the middle ear

The structure is quite complex. The ear labyrinth has many components. It starts from the tympanic membrane and is located in the pyramid of the temporal bone. The middle ear cavity can be divided into several parts:

• Direct middle ear cavity
• auditory trumpet
• auditory ossicles

Consider what each of these parts is, and what functional features they have.

What is the tympanic cavity? It is located in the temporal bone. Its volume is 1 cubic centimeter. It is in this cavity that the auditory ossicles are located, which are connected to the eardrum. There is a small process above the cavity, its structure is presented in the form of small cells that have an air-bearing structure. It is in it that a special air cell is located. She plays an important role. In human anatomy, it is she who plays the role of the main reference point in the performance of any operational actions on the auditory organ.

The auditory tube has a diameter of approximately 35 mm. Its upper mouth is located in the tympanic cavity. On the size of the hard palate, where the nasopharynx is located, the pharyngeal mouth is found. Thus, the tympanic cavity using the auditory tube can contact the nasopharynx. By itself, the auditory tube is intended to equalize the pressure on both edges of the eardrum.

The auditory tube is divided into two sections, which are separated by the narrowest point. In medical textbooks, it is called the isthmus. Bone tissue moves away from the eardrum, but below is already cartilage tissue. In the normal state, the walls of the auditory tube are closed. They can open during chewing, yawning or swallowing. This expansion is made possible by two muscles that are interconnected. The inner cavity of this tube is additionally covered with a thin layer of skin, on which small cilia are located. Thanks to them, a drainage function is provided.

In addition, the auditory ossicles are located in the middle ear, they are presented in the form of an anvil, hammer and stirrup, which are combined with each other using movable tissue. After the auricle picks up certain sounds, they are transmitted to the eardrum, subsequently its vibrations to the hammer. With the help of the anvil, vibrations are transmitted to the stirrup and only then enter the inner ear.

Thanks to these bones, the amplitude is significantly reduced, but the strength of the sound is multiplied. The middle ear is separated by an inner wall. It has two holes: one is round and the other is oval, both of them are covered with a membrane. It is at the base of the oval hole that the base of the stirrup is located, which leads to the inner ear.

The structure of the inner ear

Its structure is somewhat reminiscent of a labyrinth. This part is located in the pyramid of the temporal bone. Inside it is a bone capsule and membranous formation. It exactly repeats the shape of the capsule. The bony labyrinth consists of:

• vestibule
• snails
• Three semicircular canals

The anatomy of the human ear is arranged in such a way that the main sound function here is performed by the cochlea, which is a spirally twisted canal of bone tissue, approximately 2.75 turns. Its height is 5 mm, and its length is 3.2 cm. Inside the cochlea there is another labyrinth, which is completely filled with endolithm. Between the membranous and bony canals is a small space filled with perilymph. With the help of a spiral plate, the labyrinth is divided into two channels.

What are the substances that fill the cavity inside the cochlea? Endolithma is a viscous component and is similar in composition and consistency to the intracellular fluid. Perelhythm in its composition is very similar to blood plasma.

The membranous labyrinth with the help of special strands should always be in limbo. If this equilibrium is disturbed, this will lead to a sharp increase in pressure in this labyrinth.

The cochlea plays an important role in the organ of hearing. Fluctuations in its internal fluid lead to the formation of electrical impulses that are transmitted using the auditory nerve to the brain. This is how the human ear works.

In the membranous canal of the cochlea there is a special sound-receiving apparatus, which is called the spiral organ. It has its own structure: it consists of a membrane on which receptor cells are located, and an integumentary membrane.

The central membrane serves to separate the membranous labyrinth. It includes fibers, they have different lengths. The fibers are located across the course of the cochlea. The longest of them are located at the top of the cochlea, and the shortest, respectively, from the bottom.

In addition, there are receptor cells on the membrane that pick up sound. They are elongated. In this case, one end of the cell is attached to the membrane, while the other is not fixed and ends with several hairs. From the fixed part of the cells come the fibers of the auditory nerve. Hairs from the other end of the cell are washed by the endolithm and can be combined with the integumentary membrane.

One of the most ancient components of the ears is the cavity, which is adjacent to the scala cochlea and the semicircular canals. It is called the vestibule, on the walls of which there are two small windows: one is covered with a stirrup, and the second resembles a tympanic membrane.

In addition to perceiving sounds, human ears also perform other functions, for example, regulating the position of the human body in a certain position. This is done with the help of the vestibular apparatus. Separately, I would like to mention the semicircular bone canals. They have a similar structure to each other. . Inside each of them there is a channel that repeats its curves. It is these channels and vestibules that are responsible for balance and coordination, helping our body to occupy the necessary position in space.

The semicircular canals and the vestibule are filled with a special fluid. Two small sacs are located on the threshold, they also contain contents inside themselves - the endolithm, which was already mentioned above. In addition to the liquid, the bags contain limestone pebbles. On the walls of these sacs there are many hair-shaped receptor cells.

The semicircular canals are located in several planes and are also filled with fluid. Inside them, as in the vestibule, there are also receptors in the form of small hairs. How does this whole system work?

If the position of the human body begins to change, the fluid that is contained inside the semicircular canals is set in motion. Because of this, the calcareous pebbles inside the sacs also begin to move. Due to this, the receptors of the vestibular apparatus come into a state of irritation. This excitation passes to the fibers of the vestibular nerve, and already from it the cerebral cortex receives a signal.

Thus, a person forms the correct position of the body. In newborns, all these processes are not fully developed, which is why it is so difficult for babies to keep balance, start raising their heads and walking. Gradually, as parents teach the child elementary skills, the process of formation of all parts of the ear goes on, and each time it becomes easier for the child to move and maintain the desired position.

The most common disease of the inner ear is hearing loss. The sound that is in the ear has features such as amplitude and frequency. Amplitude is the force with which sound waves exert a corresponding amount of pressure on the eardrum. The number of vibrations of a sound wave in one second is the frequency. If a person cannot distinguish between sounds and frequencies, hearing loss occurs.

In this case, the disease has several varieties. With sensorineural hearing loss, the functions of the auditory nerve are significantly damaged or there are violations of the sensitivity of the cochlea. Conductive hearing loss occurs when sound is transmitted between the outer and middle ear. In the case of mixed hearing loss, both disorders can be observed.

The structure of the ear in newborns

In a newly born child, the organs of hearing are different from the ears of an adult. Babies have not yet fully formed their ears. Its structure changes and supplements over time. In a newborn child, the auricle is very pliable, the curl and earlobe are formed only by 4 years.

In the ear canal, the bone tissue is not yet formed. Its walls are located almost close to each other. At the same time, the tympanic membrane is in a horizontal position. Despite this, the tympanic membrane is completely formed and practically does not differ in structure and dimensions from the membrane of an adult. In addition, in young children it is noticeably thicker than in an adult, and is covered with a mucous membrane.

There is a gap in the upper part of the tympanic cavity, which overgrows with time. It is through it that an infection can enter the brain of a small child. It occurs during acute otitis media and can form more serious illnesses. Inside the cavity, the mastoid process is not yet formed and is presented as a cavity. Its development begins only by 2 years and is fully formed at the age of 6 years. The auditory tube in newborns is much wider and shorter than in adults and is located horizontally.

As you can see, the structure of the ear is a rather complex device that simultaneously performs 2 functions. Our auditory organ is designed to protect us from various dust, microorganisms and infection. Protects us from too loud sounds and helps to maintain balance. To understand exactly how each mechanism of this complex system works, let's consider how the perception of sound by a person is carried out.

Sound perception mechanism

Sound vibrations enter the ear through the external passage, hit the tympanic membrane and, with the help of the auditory ossicles, through the membrane of the oval window are transmitted to the endolithm and perilythm. Vibrations inside them cause irritation of sensitive fibers of different lengths. At this point, the hair cells invade the membrane. This excitement is directed towards auditory nerve. During such processes, mechanical energy is transformed into electrical energy.

Receptors of various lengths can be excited, it all depends on the length of the sound wave. Vibration of high fibers causes higher tones, while long fibers vibrate from low tones. The assessment of the perceived sound is made in the temporal part of the forebrain cortex.

To do this, you need to follow simple rules. Wash your ears regularly with warm water and soap. In the outer part of the ear, along with sulfur, dust and various microorganisms accumulate. It is impossible for this content to accumulate for a long time in the outer passage. Infra-low and ultra-high frequencies, constant noise indoors and outdoors, very unpleasant and loud sound can have a traumatic effect on the auditory analyzer. As a result, you can reduce or completely lose your hearing.

In order to overcome these negative impacts and protect the hearing organs, a number of protective measures are taken at the workplace. To do this, employees are given special protective headphones that have anti-noise properties. In addition, a certain decoration of the room can be used - wall cladding that absorbs sound.

Do not forget to treat diseases of the nasopharynx in a timely manner. Through the nasal tube, dangerous microorganisms and infection can enter the tympanic cavity, which will then cause an inflammatory process in the organ of hearing.

Hearing circulatory system

Special attention should be paid to these functions, especially for those who want to study in detail how the ear functions, the circulatory device, which, by the way, is provided with the help of the trigeminal nerve and the cervical plexus. The auricular nerves provide blood supply to the pinna muscle. The main blood supply is carried out using the external carotid artery.

The structure of the ear is a unique and complex mechanism. Thanks to him, we can perceive various sounds, hear the interlocutor, sing, write music and much more. The organ of hearing helps us communicate, correctly forms our speech. In addition, it is with its help that we can maintain a certain position and maintain balance. Do not forget to monitor this important organ, carry out hygiene procedures, protect yourself from negative external factors and consult a doctor in time for help.

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Everyone knows that the human ear has a complex structure: the outer, middle and inner ear. The middle ear plays an important role in the entire auditory process, as it performs a sound-conducting function. Diseases occurring in the middle ear pose a direct threat to human life. Therefore, to study the structure, functions and methods of protecting the middle ear from infections is a very urgent task.

Organ structure

The middle ear is located deep in the temporal bone and is represented by the following organs:

• tympanic cavity;
• auditory tube;
• mastoid.

The middle ear is arranged as a collection of air cavities. Its central part is the tympanic cavity - the area between the inner ear and the tympanic membrane. It has a mucous surface and resembles a prism or a tambourine. The tympanic cavity is separated from the skull by the upper wall.

The anatomy of the middle ear provides for the separation of its bone wall from the inner ear. There are 2 holes in this wall: round and oval. Each opening, or window, is protected by an elastic membrane.

The middle ear cavity also contains the auditory ossicles, which transmit sound vibrations. These bones include: hammer, anvil and stirrup. The names of the bones arose in connection with the peculiarities of their structure. The mechanism of interaction of the auditory ossicles resembles a system of levers. The hammer, anvil and stirrup are connected by joints and ligaments. In the center of the tympanic membrane is the handle of the malleus, its head is connected to the anvil, and it is connected by a long process to the head of the stirrup. The stirrup enters the foramen ovale, behind which is the vestibule, the fluid-filled part of the inner ear. All bones are covered with a mucous membrane.

An important element of the middle ear is the auditory tube. It connects the tympanic cavity with the external environment. The mouth of the tube is located at the level of the hard palate and opens into the nasopharynx. The mouth of the auditory tube is closed when there are no sucking or swallowing movements. There is one feature of the structure of the tube in newborns: it is wider and shorter than in an adult. This fact facilitates the penetration of viruses.

The mastoid process is a process of the temporal bone, which is located behind it. The structure of the process is cavitary, since it contains cavities filled with air. The cavities communicate with each other through narrow gaps, which allows the middle ear to improve its acoustic properties.

The structure of the middle ear also suggests the presence of muscles. The tensor tympanic membrane and the stirrup are the smallest muscles in the entire body. With their help, the auditory ossicles are supported by weight, regulated. In addition, the muscles of the middle ear provide accommodation of the organ to sounds of different height and strength.

Purpose and functions

The functioning of the organ of hearing without this element is impossible. The middle ear contains the most important components, which together perform the function of sound conduction. Without the middle ear, this function could not be realized and the person would not be able to hear.

The auditory ossicles provide bone conduction of sound and mechanical transmission of vibrations to the oval window of the vestibule. 2 small muscles perform a number of important tasks for hearing:

• maintain the tone of the tympanic membrane and the mechanism of the auditory ossicles;
• protect the inner ear from strong sound irritations;
• provide accommodation of the sound-conducting apparatus to sounds of different strength and height.

Based on the functions that the middle ear performs with all its components, we can conclude that without it, the auditory function would be unfamiliar to a person.

Diseases of the middle ear

Ear diseases are one of the most unpleasant ailments for a person. They carry a great danger not only to health, but also to human life. The middle ear, as the most important part of the auditory organ, is subject to various diseases. Leaving the disease of the middle ear untreated, a person runs the risk of becoming hard of hearing and significantly reduce the quality of his life.

Among inflammatory diseases meet:

1. Purulent otitis media refers to complex inflammatory processes. It is characterized by pronounced symptoms: shooting pains, purulent-bloody discharge from the ear, significant hearing loss. With this disease, the eardrum is affected, so it is extremely dangerous to delay treatment of purulent otitis media. The disease can go into a chronic stage.
2. Epitympanitis occurs when the tissue of the outer ear grows into the cavity of the tympanic membrane. This process is dangerous because the bone structure of the inner and middle ear can be broken. On good quality hearing in this case is not worth counting.
3. Mesotympanitis develops when the mucous membrane of the central part of the eardrum is inflamed. The patient suffers from a decrease in the quality of hearing and frequent purulent discharge.
4. Cicatricial otitis media - restriction of mobility of the mechanism of the auditory ossicles. With such otitis, a very dense connective tissue is formed. The main function of the bones - the conduction of sound - is significantly deteriorating.

Some diseases may lead to dangerous complications. For example, epitympanitis is able to destroy the upper wall of the tympanic cavity and expose a solid meninges. Purulent chronic otitis media is dangerous because complications can not only affect the region of the temporal bone, but also penetrate deep into the cranial cavity.

The hallmark of middle ear infections is that it is much harder to get to because the middle ear is deep. In addition, conditions are very favorable for infection, so treatment cannot be delayed. If you experience any strange, unpleasant sensations in the ear, you must urgently contact an otolaryngologist to eliminate the risk of danger to life and health. Doctors categorically do not recommend self-medication. Treatment of hearing diseases without qualified help can adversely affect the entire auditory process.

Disease protection measures

Reduced immunity becomes the main source for the appearance and development of infections. To reduce the risk of middle ear infections, it is necessary to take vitamins, to exclude hypothermia. It is necessary to do everything so that the immune system provides maximum resistance to any diseases. It is useful to use decoctions from medicinal herbs for the prevention of inflammatory diseases.

Regular visits to a specialist will identify any changes in the structure of the auditory organ and prevent the development of certain diseases. To examine the condition of the middle ear, the doctor uses a special device - an otoscope. It is impossible to penetrate the middle ear with the help of improvised means, therefore any unskilled intervention in the ear is dangerous - there is a risk of mechanical damage.

The disease must be cured until it disappears completely. Otherwise, even ordinary otitis media can lead to dangerous complications.

In general, otitis media responds effectively fast treatment, the main thing is to consult a doctor in time, do not self-medicate and monitor the general state of your health.

The ear has two main functions: the organ of hearing and the organ of balance. The organ of hearing is the main of the information systems that take part in the formation of the speech function, and therefore, the mental activity of a person. Distinguish between outer, middle and inner ear.

Outer ear - auricle, external auditory meatus

Middle ear - tympanic cavity, auditory tube, mastoid process

Inner ear (labyrinth) - cochlea, vestibule and semicircular canals.

The outer and middle ear provide sound conduction, and the receptors for both auditory and vestibular analyzers are located in the inner ear.

Outer ear. The auricle is a curved plate of elastic cartilage, covered on both sides with perichondrium and skin. The auricle is a funnel that provides optimal perception of sounds in a certain direction of sound signals. It also has significant cosmetic value. Such anomalies of the auricle are known as macro- and microotia, aplasia, protrusion, etc. Disfigurement of the auricle is possible with perichondritis (trauma, frostbite, etc.). Its lower part - the lobe - is devoid of a cartilaginous base and contains adipose tissue. In the auricle, a curl (helix), an antihelix (anthelix), a tragus (tragus), an antitragus (antitragus) are distinguished. The curl is part of the external auditory meatus. The external auditory meatus in an adult consists of two sections: the external one is membranous-cartilaginous, equipped with hairs, sebaceous glands and their modifications - earwax glands (1/3); internal - bone, not containing hair and glands (2/3).

Topographic and anatomical ratios of the parts of the ear canal have clinical significance. front wall - borders on the articular bag of the lower jaw (important for external otitis media and injuries). Bottom - the parotid gland is adjacent to the cartilaginous part. The anterior and lower walls are pierced with vertical fissures (santorini fissures) in the amount of 2 to 4, through which suppuration can pass from the parotid gland to the auditory canal, as well as in the opposite direction. rear – borders on the mastoid process. In the depths of this wall is the descending part of the facial nerve (radical surgery). Upper – borders on the middle cranial fossa. Upper back – is the anterior wall of the antrum. Its omission indicates purulent inflammation of the cells of the mastoid process.

The outer ear is supplied with blood from the external carotid artery system due to the superficial temporal (a. temporalis superficialis), occipital (a. occipitalis), posterior auricular and deep ear arteries (a. auricularis posterior et profunda). Venous outflow is carried out in the superficial temporal (v. temporalis superficialis), external jugular (v. jugularis ext.) and maxillary (v. maxillaris) veins. Lymph is drained to the lymph nodes located on the mastoid process and anterior to the auricle. Innervation is carried out by branches of the trigeminal and vagus nerve, as well as from the ear nerve from the superior cervical plexus. Due to the vagal reflex with sulfur plugs, foreign bodies, cardialgic phenomena, cough are possible.

The boundary between the outer and middle ear is the tympanic membrane. The tympanic membrane (Fig. 1) is approximately 9 mm in diameter and 0.1 mm thick. The tympanic membrane serves as one of the walls of the middle ear, tilted forward and down. In an adult, it is oval in shape. B / p consists of three layers:

external - epidermal, is a continuation of the skin of the external auditory canal,

internal - mucous lining the tympanic cavity,

the fibrous layer itself, located between the mucous membrane and the epidermis and consisting of two layers of fibrous fibers - radial and circular.

The fibrous layer is poor in elastic fibers, so the tympanic membrane is not very elastic and can rupture with sharp pressure fluctuations or very strong sounds. Usually, after such injuries, a scar subsequently forms due to the regeneration of the skin and mucous membrane, the fibrous layer does not regenerate.

In b / p, two parts are distinguished: stretched (pars tensa) and loose (pars flaccida). The stretched part is inserted into the bony tympanic ring and has a middle fibrous layer. Loose or relaxed attached to a small notch of the lower edge of the scales of the temporal bone, this part does not have a fibrous layer.

On otoscopic examination, the color is b / n pearly or pearl gray with a slight sheen. For the convenience of clinical otoscopy, the b/p is mentally divided into four segments (antero-superior, anterior-inferior, posterior-superior, posterior-inferior) by two lines: one is a continuation of the malleus handle to the lower edge of the b/p, and the second passes perpendicular to the first through the navel b/p.

Middle ear. The tympanic cavity is a prismatic space in the thickness of the base of the pyramid of the temporal bone with a volume of 1-2 cm³. It is lined with a mucous membrane that covers all six walls and passes behind into the mucous membrane of the cells of the mastoid process, and in front into the mucous membrane of the auditory tube. It is represented by a single-layer squamous epithelium, with the exception of the mouth of the auditory tube and the bottom of the tympanic cavity, where it is covered with ciliated cylindrical epithelium, the movement of the cilia of which is directed towards the nasopharynx.

External (webbed) the wall of the tympanic cavity for a greater extent is formed by the inner surface of the b / n, and above it - by the upper wall of the bone part of the auditory canal.

Internal (labyrinth) the wall is also the outer wall of the inner ear. In its upper section there is a vestibule window, closed by the base of the stirrup. Above the window of the vestibule is a protrusion of the facial canal, below the window of the vestibule - a round-shaped elevation, called the cape (promontorium), corresponds to the protrusion of the first whorl of the cochlea. Below and behind the cape is a snail window, closed by a secondary b/p.

Upper (tire) the wall is a rather thin bony plate. This wall separates the middle cranial fossa from the tympanic cavity. Dehiscences are often found in this wall.

Inferior (jugular) wall - formed by the stony part of the temporal bone and is located 2-4.5 mm below the b / p. It borders on the bulb of the jugular vein. Often there are numerous small cells in the jugular wall that separate the bulb of the jugular vein from the tympanic cavity, sometimes dehiscences are observed in this wall, which facilitates the penetration of infection.

Anterior (sleepy) the wall in the upper half is occupied by the tympanic mouth of the auditory tube. Its lower part borders on the canal of the internal carotid artery. Above the auditory tube is a semi-channel of the muscle that strains the eardrum (m. tensoris tympani). The bone plate separating the internal carotid artery from the mucous membrane of the tympanic cavity is permeated with thin tubules and often has dehiscences.

Posterior (mastoid) the wall borders on the mastoid process. The entrance to the cave opens in the upper section of its back wall. In the depths of the posterior wall, the canal of the facial nerve passes, from this wall the stirrup muscle begins.

Clinically, the tympanic cavity is conditionally divided into three sections: the lower (hypotympanum), middle (mesotympanum), upper or attic (epitympanum).

The auditory ossicles involved in sound conduction are located in the tympanic cavity. The auditory ossicles - hammer, anvil, stirrup - are a closely connected chain that is located between the tympanic membrane and the vestibule window. And through the vestibule window, the auditory ossicles transmit sound waves to the fluid of the inner ear.

Hammer - it distinguishes the head, neck, short process and handle. The handle of the malleus is fused with the b/p, the short process protrudes outwards the upper section of the b/p, and the head articulates with the body of the anvil.

Anvil - it distinguishes the body and two legs: short and long. The short leg is placed at the entrance to the cave. The long leg is connected to the stirrup.

stirrup - it distinguishes head, anterior and posterior legs, interconnected by a plate (base). The base covers the window of the vestibule and is strengthened with the window with the help of an annular ligament, due to which the stirrup is movable. And this provides a constant transmission of sound waves to the fluid of the inner ear.

Muscles of the middle ear. Tensing muscle b / n (m. tensor tympani), innervated trigeminal nerve. The stirrup muscle (m. stapedius) is innervated by a branch of the facial nerve (n. stapedius). The muscles of the middle ear are completely hidden in the bone canals, only their tendons pass into the tympanic cavity. They are antagonists, they contract reflexively, protecting the inner ear from excessive amplitude of sound vibrations. Sensory innervation the tympanic cavity is provided by the tympanic plexus.

The auditory or pharyngeal-tympanic tube connects the tympanic cavity with the nasopharynx. The auditory tube consists of bone and membranous-cartilaginous sections, opening into the tympanic cavity and nasopharynx, respectively. The tympanic opening of the auditory tube opens in the upper part of the anterior wall of the tympanic cavity. The pharyngeal opening is located on the side wall of the nasopharynx at the level of the posterior end of the inferior turbinate 1 cm posterior to it. The hole lies in a fossa bounded above and behind by a protrusion of tubal cartilage, behind which there is a depression - Rosenmuller's fossa. The mucous membrane of the tube is covered with multinuclear ciliated epithelium (the movement of cilia is directed from the tympanic cavity to the nasopharynx).

The mastoid process is a bone formation, according to the type of structure of which they distinguish: pneumatic, diploetic (consists of spongy tissue and small cells), sclerotic. The mastoid process through the entrance to the cave (aditus ad antrum) communicates with the upper part of the tympanic cavity - the epitympanum (attic). In the pneumatic type of structure, the following groups of cells are distinguished: threshold, perianthral, ​​angular, zygomatic, perisinus, perifacial, apical, perilabyrinthine, retrolabyrinthine. At the border of the posterior cranial fossa and mastoid cells, there is an S-shaped recess to accommodate the sigmoid sinus, which drains venous blood from the brain to the bulb of the jugular vein. Sometimes the sigmoid sinus is located close to the ear canal or superficially, in this case they speak of sinus presentation. This must be borne in mind during surgical intervention on the mastoid process.

The middle ear is supplied by branches of the external and internal carotid arteries. Venous blood drains into the pharyngeal plexus, bulb of the jugular vein, and middle cerebral vein. Lymphatic vessels carry lymph to the retropharyngeal lymph nodes and deep nodes. The innervation of the middle ear comes from the glossopharyngeal, facial and trigeminal nerves.

Due to the topographic and anatomical proximity facial nerve to the formations of the temporal bone, we trace its course. The trunk of the facial nerve is formed in the region of the cerebellopontine triangle and is sent along with the VIII cranial nerve to the internal auditory meatus. In the thickness of the stony part of the temporal bone, near the labyrinth, its stony ganglion is located. In this zone, a large stony nerve branches off from the trunk of the facial nerve, containing parasympathetic fibers for the lacrimal gland. Further, the main trunk of the facial nerve passes through the thickness of the bone and reaches the medial wall of the tympanic cavity, where it turns posteriorly at a right angle (the first knee). The bone (fallopian) nerve canal (canalis facialis) is located above the window of the vestibule, where the nerve trunk can be damaged during surgical interventions. At the level of the entrance to the cave, the nerve in its bone canal goes steeply down (the second knee) and exits the temporal bone through the stylomastoid foramen (foramen stylomastoideum), splitting fan-shaped into separate branches the so-called goose foot (pes anserinus), innervating the facial muscles. At the level of the second knee, the stirrup departs from the facial nerve, and caudally, almost at the exit of the main trunk from the stylomastoid foramen, there is a tympanic string. The latter passes in a separate tubule, penetrates the tympanic cavity, heading anteriorly between the long leg of the anvil and the handle of the malleus, and leaves the tympanic cavity through the stony-tympanic (glazer) fissure (fissura petrotympanical).

inner ear lies in the thickness of the pyramid of the temporal bone, two parts are distinguished in it: the bone and membranous labyrinth. In the bony labyrinth, the vestibule, cochlea, and three bony semicircular canals are distinguished. The bony labyrinth is filled with fluid - perilymph. The membranous labyrinth contains endolymph.

The vestibule is located between the tympanic cavity and the internal auditory canal and is represented by an oval-shaped cavity. The outer wall of the vestibule is the inner wall of the tympanic cavity. The inner wall of the vestibule forms the bottom of the internal auditory meatus. It has two recesses - spherical and elliptical, separated from each other by a vertically running crest of the vestibule (crista vestibule).

The bony semicircular canals are located in the posterior inferior part of the bony labyrinth in three mutually perpendicular planes. There are lateral, anterior and posterior semicircular canals. These are arcuate curved tubes in each of which two ends or bone legs are distinguished: expanded or ampullar and non-expanded or simple. The simple bony pedicles of the anterior and posterior semicircular canals join to form a common bony pedicle. The canals are also filled with perilymph.

The bony cochlea begins in the anteroinferior part of the vestibule with a canal, which spirally bends and forms 2.5 curls, as a result of which it was called the spiral canal of the cochlea. Distinguish between the base and the top of the cochlea. The spiral canal winds around a cone-shaped bone rod and ends blindly in the region of the top of the pyramid. The bone plate does not reach the opposite outer wall of the cochlea. The continuation of the spiral bone plate is the tympanic plate of the cochlear duct (basic membrane), which reaches the opposite wall of the bone canal. The width of the spiral bone plate gradually narrows towards the apex, and the width of the tympanic wall of the cochlear duct increases accordingly. Thus, the shortest fibers of the tympanic wall of the cochlear duct are at the base of the cochlea, and the longest at the apex.

The spiral bone plate and its continuation - the tympanic wall of the cochlear duct divide the cochlear canal into two floors: the upper one is the scala vestibuli and the lower one is the scala tympani. Both scalas contain perilymph and communicate with each other through an opening at the top of the cochlea (helicotrema). The scala vestibuli borders on the vestibule window, closed by the base of the stirrup, the scala tympani borders on the cochlear window, closed by the secondary tympanic membrane. The perilymph of the inner ear communicates with the subarachnoid space through the perilymphatic duct (cochlear aqueduct). In this regard, suppuration of the labyrinth can cause inflammation of the meninges.

The membranous labyrinth is suspended in the perilymph, filling the bony labyrinth. In the membranous labyrinth, two apparatuses are distinguished: vestibular and auditory.

The hearing aid is located in the membranous cochlea. The membranous labyrinth contains endolymph and is a closed system.

The membranous cochlea is a spirally wrapped canal - the cochlear duct, which, like the cochlea, makes 2½ turns. In cross section, the membranous cochlea has a triangular shape. It is located in the upper floor of the bony cochlea. The wall of the membranous cochlea, bordering the scala tympani, is a continuation of the spiral bone plate - the tympanic wall of the cochlear duct. The wall of the cochlear duct, bordering the scala vestibulum - the vestibular plate of the cochlear duct, also departs from the free edge of the bone plate at an angle of 45º. The outer wall of the cochlear duct is part of the outer bony wall of the cochlear canal. A vascular strip is located on the spiral ligament adjacent to this wall. The tympanic wall of the cochlear duct consists of radial fibers arranged in the form of strings. Their number reaches 15000 - 25000, their length at the base of the cochlea is 80 microns, at the top - 500 microns.

The spiral organ (Corti) is located on the tympanic wall of the cochlear duct and consists of highly differentiated hair cells supporting them with columnar and supporting Deiters cells.

The upper ends of the inner and outer rows of columnar cells are inclined towards each other, forming a tunnel. The outer hair cell is equipped with 100 - 120 hairs - stereocilia, which have a thin fibrillar structure. The plexuses of nerve fibers around the hair cells are guided through tunnels to the spiral knot at the base of the spiral bone plate. In total, there are up to 30,000 ganglion cells. The axons of these ganglion cells connect in the internal auditory canal to the cochlear nerve. Above the spiral organ is an integumentary membrane, which begins near the place of discharge of the vestibulum wall of the cochlear duct and covers the entire spiral organ in the form of a canopy. The stereocilia of hair cells penetrate the integumentary membrane, which plays a special role in the process of sound reception.

The internal auditory meatus begins with an internal auditory opening located on the posterior face of the pyramid and ends with the bottom of the internal auditory meatus. It contains the perdoor-cochlear nerve (VIII), consisting of the upper vestibular root and the lower cochlear. Above it is the facial nerve and next to it is the intermediate nerve.