The structure of the human middle ear. The structure of the human ear. Structure of the middle and inner ear

The human ear is a unique organ, the structure of which has a rather complex structure. However, at the same time it works very simply. Hearing organ a person is able to receive sound signals, can amplify them and convert them from simple vibrations of a mechanical nature into nervous ones electrical impulses.

The human ear includes a large number of complex parts, the study of which is a whole science. Today you will see photos of diagrams of its structure, learn how the outer, middle and inner ears differ from each other and how the auricle works.

Auricle: structure

It is known that the human ear is paired organ, which is located in the temporal part of the human skull. However, we cannot study the structure of the auricle ourselves, since our auditory canal is located too deep. We can only see the ears with our own eyes. The ear has the ability to perceive sound waves with a length of 20 m or 20 thousand mechanical vibrations per unit of time.

The ear is an organ that is responsible for a person’s ability to hear. And so that it can correctly perform this function, the following parts of it are used:

Also the ear includes the following parts:

• lobe;
• tragus;
• antitragus;
• antihelix;
• curl.

The auricle is attached to the temple with the help of special muscles, which are called vestigial.

Such a structure of this organ exposes it to many negative influences from the outside, also the ear is susceptible to inflammation or otohematomas. There are pathological conditions, some of which are congenital in nature and may be reflected in the underdevelopment of the auricle.

Outer ear: structure

The outer part of the human ear is formed by the pinna and the outer ear canal. The shell has the appearance of dense elastic cartilage, which is covered with skin on top. At the bottom there is a lobe - this is a single fold of skin and fatty tissue. This structure of the auricle is such that it is not very stable and is very sensitive to even minimal mechanical damage. Quite often you can find professional athletes who have acute ear deformities.

This part of the ear is the so-called receiver of mechanical sound waves, as well as the frequencies around us. It is the concha that is responsible for relaying signals from the outside into the ear canal.

It is equipped with folds that can accept and handle frequency distortion. All this is necessary so that the brain is able to perceive the required information for orientation on the ground, i.e. performs a navigation function. Also, this part of the ear is capable of creating surround stereo sound in the ear canal.

It can pick up sounds within a radius of 20 meters, this is due to the fact that the shell connects directly to the ear canal. And then the passing cartilage passes into bone tissue.

The ear canal includes cerumen glands, which are responsible for the formation of wax, which will be needed to protect the ear from the negative effects of bacteria. The sound waves that the sink receives then enter the passage and then they are removed against the membrane. And so that it does not burst when elevated level noise, it is recommended to open your mouth at this moment, this repels the sound wave from the membrane. From the auricle, all vibrations of sound and noise pass to the middle ear.

Structure of the middle ear

The clinical form of the middle ear has the appearance of a tympanic cavity. It is located next to the temporal bone and is a vacuum space. The auditory bones are located here:

• stapes;
• hammer;
• anvil.

They all convert noise to the side inner ear from the outside.

If you look in detail at the structure of the auditory ossicles, you can note that they resemble a connected chain, transmitting sound vibrations. The handle of the malleus is closely located near the eardrum, then the head of the malleus is attached to the incus, which, in turn, is already connected to the stapes. If the operation of one of these parts of the circuit is disrupted, the person may experience hearing problems.

Anatomically, the middle ear is connected to the nasopharynx. The Eustachian tube is used as a connecting link; it regulates the pressure of the air that enters from the outside. When the ambient pressure sharply decreases or increases, the person complains of blocked ears. Therefore, a change in weather affects your well-being.

Indicates active protection of the brain from damage strong headache turning into migraine. When external pressure changes, the body reacts to it by yawning. To get rid of this, you need to swallow saliva a couple of times or blow sharply into your pinched nose.

Unlike the outer and middle ear, the inner ear has the most complex structure; otolaryngologists call it a labyrinth. This part of the ear includes:

• vestibule;
• snails;
• semicircular tubules.

Then the division occurs according to the anatomical forms of the labyrinth.

In anticipation of the cochlea, sac and queen join to form the endolymphatic duct. Here it is clinical form receptor fields. Next are the semicircular canals:

• front;
• rear;
• lateral.

Each of these canals has a pedicle and an ampullary end.

The inner ear has the shape of a cochlea, its parts are:

• staircase vestibule;
• duct;
• scala tympani;
• organ of Corti.

Pillar cells are located in the organ of Corti.

Physiological characteristics of human ears

Our hearing organ in the body has two key purposes:

• forms and maintains balance human body;
• receives and converts noise and vibrations into sound forms.

In order for us to be in balance even during rest, and not just when moving, the vestibular apparatus must work constantly. But not everyone knows that our ability to walk on two legs in a straight line lies in the structural features of the inner ear. This mechanism is based on the principle of communicating vessels, which have the shape of an auditory organ.

This organ includes the semicircular canals, which maintain fluid pressure in our body. When a person changes body position (changes rest for movement and vice versa), but the clinical structure of the hearing organ is able to adapt to one or another physiological state and regulates intracranial pressure.

Human sound sensations and their nature

Is a person capable of feeling all vibrations in the air? Not really. A person can transform air vibrations only from 16 to thousands of hertz, but we are no longer able to hear infra- and ultrasounds. Thus, infrasounds in nature can appear in the following cases:

• lightning strike;
• earthquake;
• Hurricane;
• storm.

Elephants and whales are especially sensitive creatures to infrasound. They seek shelter when a hurricane or storm approaches. But ultrasounds can be heard by moths, bats and some species of birds. The perception of this type of vibration in nature called echolocation. It is used in such areas as:

• cosmetology;
• medicine;
• different types production

So, we have learned that the structure of the ear includes three main parts:

• external;
• average;
• internal.

Each part has its own anatomical features, which determine their functions. The outer part includes the auricle and the external meatus, the middle part includes the auditory ossicles, and the inner part contains sensitive hairs, respectively. Together, their work is ensured by the ear entry into sound vibration receptors, converting them into nerve impulses, then they are transmitted through neural processes to the central part of the human sensory system.

It is very important to include ear care in your daily hygiene, because if its functional levers are impaired, this can cause hearing loss or a number of diseases related to problems of the middle, inner or outer ear.

Hearing loss leads a person to partial isolation from the outside world, naturally, which is not the same as with vision loss, but the psychological component here is also very strong. Therefore, regularly taking care of your hearing organs and consulting a doctor if something bothers you in this regard is very important for each of us.

The ear is a complex organ in humans and animals, through which sound vibrations are perceived and transmitted to the main nerve center of the brain. The ear also performs the function of maintaining balance.

As everyone knows, the human ear is a paired organ located deep in the temporal bone of the skull. Externally, the ear is limited by the auricle. It is the direct receiver and conductor of all sounds.

The human hearing aid can perceive sound vibrations whose frequency exceeds 16 Hertz. The maximum sensitivity threshold of the ear is 20,000 Hz.

Structure of the human ear

The human hearing system includes:

1. External part
2. middle part
3. Interior

In order to understand the functions performed by certain components, it is necessary to know the structure of each of them. Enough complex mechanisms Sound transmissions allow a person to hear sounds in the form in which they come from the outside.

• Inner ear. It is the most complex component of the hearing aid. The anatomy of the inner ear is quite complex, which is why it is often called the membranous labyrinth. It is also located in the temporal bone, or more precisely, in its petrous part.
  The inner ear is connected to the middle ear through oval and round windows. The membranous labyrinth includes the vestibule, cochlea, and semicircular canals filled with two types of fluid: endolymph and perilymph. Also in the inner ear is vestibular system, responsible for a person’s balance and his ability to accelerate in space. The vibrations that arise in the oval window are transferred to the liquid. With its help, the receptors located in the cochlea are irritated, which leads to the formation of nerve impulses.

The vestibular apparatus contains receptors that are located on the cristae of the canals. They come in two types: cylinder and flask. The hairs are opposite each other. Stereocilia during displacement cause excitation, and kinocilia, on the contrary, contribute to inhibition.

For a more accurate understanding of the topic, we bring to your attention a photo diagram of the structure of the human ear, which shows the complete anatomy of the human ear:

As you can see, the human hearing system is a rather complex system of various formations that perform a number of important, irreplaceable functions. As for the structure of the outer part of the ear, each person may have individual characteristics that do not harm the main function.

Hearing aid care is an integral part of human hygiene, because as a result functional disorders There may be hearing loss, as well as other diseases associated with the outer, middle or inner ear.

According to scientific research, a person is more difficult to tolerate vision loss than hearing loss, because he loses the ability to communicate with environment, that is, it becomes isolated.

And morphologists call this structure organelukha and balance (organum vestibulo-cochleare). It has three sections:

• external ear (external auditory canal, auricle with muscles and ligaments);
• middle ear (tympanic cavity, mastoid appendages, auditory tube)
• (membranous labyrinth located in the bony labyrinth inside the bone pyramid).

1. The outer ear concentrates sound vibrations and directs them to the external auditory opening.

2. The auditory canal conducts sound vibrations to the eardrum

3. The eardrum is a membrane that vibrates under the influence of sound.

4. The malleus with its handle is attached to the center of the eardrum with the help of ligaments, and its head is connected to the incus (5), which, in turn, is attached to the stapes (6).

Tiny muscles help transmit sound by regulating the movement of these ossicles.

7. The Eustachian (or auditory) tube connects the middle ear to the nasopharynx. When the ambient air pressure changes, the pressure on both sides of the eardrum is equalized through the auditory tube.

The organ of Corti consists of a number of sensory, hair-bearing cells (12) that cover the basilar membrane (13). Sound waves are picked up by hair cells and converted into electrical impulses. These electrical impulses are then transmitted along the auditory nerve (11) to the brain. The auditory nerve consists of thousands of tiny nerve fibers. Each fiber starts from a specific part of the cochlea and transmits a specific sound frequency. Low-frequency sounds are transmitted through fibers emanating from the apex of the cochlea (14), and high-frequency sounds are transmitted through fibers connected to its base. Thus, the function of the inner ear is to convert mechanical vibrations into electrical ones, since the brain can only perceive electrical signals.

Outer ear is a sound-collecting device. The external auditory canal conducts sound vibrations to the eardrum. The eardrum, which separates the outer ear from the tympanic cavity, or middle ear, is a thin (0.1 mm) partition shaped like an inward funnel. The membrane vibrates under the action of sound vibrations coming to it through the external auditory canal.

Sound vibrations are picked up by the ears (in animals they can turn towards the sound source) and transmitted through the external auditory canal to the eardrum, which separates the outer ear from the middle ear. Catching sound and the entire process of listening with two ears - so-called binaural hearing - is important for determining the direction of sound. Sound vibrations coming from the side reach the nearest ear a few ten-thousandths of a second (0.0006 s) earlier than the other. This insignificant difference in the time of arrival of sound to both ears is enough to determine its direction.

Middle ear is a sound-conducting device. It is an air cavity that connects through the auditory (Eustachian) tube to the cavity of the nasopharynx. Vibrations from the eardrum through the middle ear are transmitted by 3 auditory ossicles connected to each other - the hammer, incus and stapes, and the latter, through the membrane of the oval window, transmits these vibrations to the fluid located in the inner ear - perilymph.

Due to the peculiarities of the geometry of the auditory ossicles, vibrations of the eardrum of reduced amplitude but increased strength are transmitted to the stapes. In addition, the surface of the stapes is 22 times smaller than the eardrum, which increases its pressure on the oval window membrane by the same amount. As a result of this, even weak sound waves acting on the eardrum can overcome the resistance of the membrane of the oval window of the vestibule and lead to vibrations of the fluid in the cochlea.

During strong sounds, special muscles reduce the mobility of the eardrum and auditory ossicles, adapting the hearing aid to such changes in the stimulus and protecting the inner ear from destruction.

Thanks to the connection through the auditory tube of the air cavity of the middle ear with the cavity of the nasopharynx, it becomes possible to equalize the pressure on both sides of the eardrum, which prevents its rupture during significant changes in pressure in the external environment - when diving under water, climbing to a height, shooting, etc. This is the barofunction of the ear .

There are two muscles in the middle ear: the tensor tympani and the stapedius. The first of them, contracting, increases the tension of the eardrum and thereby limits the amplitude of its vibrations during strong sounds, and the second fixes the stapes and thereby limits its movements. The reflex contraction of these muscles occurs 10 ms after the onset of a strong sound and depends on its amplitude. This automatically protects the inner ear from overload. In case of instantaneous strong irritations (impacts, explosions, etc.), this protective mechanism does not have time to work, which can lead to hearing impairment (for example, among bombers and artillerymen).

Inner ear is a sound-perceiving apparatus. It is located in the pyramid of the temporal bone and contains the cochlea, which in humans forms 2.5 spiral turns. The cochlear canal is divided by two partitions, the main membrane and the vestibular membrane into 3 narrow passages: upper (scala vestibular), middle (membranous canal) and lower (scala tympani). At the top of the cochlea there is an opening that connects the upper and lower canals into a single one, going from the oval window to the top of the cochlea and then to the round window. Its cavity is filled with fluid - peri-lymph, and the cavity of the middle membranous canal is filled with a fluid of a different composition - endolymph. In the middle channel there is a sound-perceiving apparatus - the organ of Corti, in which there are mechanoreceptors of sound vibrations - hair cells.

The main route of delivery of sounds to the ear is airborne. The approaching sound vibrates the eardrum, and then through the chain of auditory ossicles the vibrations are transmitted to the oval window. At the same time, vibrations of the air in the tympanic cavity also occur, which are transmitted to the membrane of the round window.

Another way of delivering sounds to the cochlea is fabric or bone conduction . In this case, the sound directly acts on the surface of the skull, causing it to vibrate. Bone pathway for sound transmission acquires great importance if a vibrating object (for example, the stem of a tuning fork) comes into contact with the skull, as well as in diseases of the middle ear system, when the transmission of sounds through the chain of auditory ossicles is disrupted. In addition to the air path for conducting sound waves, there is a tissue, or bone, path.

Under the influence of airborne sound vibrations, as well as when vibrators (for example, a bone telephone or a bone tuning fork) come into contact with the integument of the head, the bones of the skull begin to vibrate (the bone labyrinth also begins to vibrate). Based on the latest data (Bekesy and others), it can be assumed that sounds propagating along the bones of the skull only excite the organ of Corti if, similar to air waves, they cause arching of a certain section of the main membrane.

The ability of the skull bones to conduct sound explains why to the person himself his voice, recorded on tape, seems foreign when the recording is played back, while others easily recognize it. The fact is that the tape recording does not reproduce your entire voice. Usually, when talking, you hear not only those sounds that your interlocutors also hear (that is, those sounds that are perceived due to air-liquid conduction), but also those low-frequency sounds, the conductor of which is the bones of your skull. However, when listening to a tape recording of your own voice, you hear only what could be recorded - sounds whose conductor is air.

Binaural hearing . Humans and animals have spatial hearing, that is, the ability to determine the position of a sound source in space. This property is based on the presence of binaural hearing, or listening with two ears. It is also important for him to have two symmetrical halves at all levels. The acuity of binaural hearing in humans is very high: the position of the sound source is determined with an accuracy of 1 angular degree. The basis for this is the ability of the neurons of the auditory system to evaluate interaural (interaural) differences in the time of sound arrival on the right and left ear and sound intensity in each ear. If the sound source is located away from the midline of the head, the sound wave arrives at one ear slightly earlier and has greater strength than at the other ear. Assessing the distance of a sound source from the body is associated with a weakening of the sound and a change in its timbre.

When the right and left ears are stimulated separately via headphones, a delay between sounds of as little as 11 μs or a 1 dB difference in the intensity of the two sounds results in an apparent shift in the localization of the sound source from the midline towards an earlier or stronger sound. The auditory centers are acutely attuned to a certain range of interaural differences in time and intensity. Cells have also been found that respond only to a certain direction of movement of a sound source in space.

EAR
organ of hearing and balance; its functions include the perception of sound waves and head movements. The perceptive apparatus of the ear is represented by a complex structure enclosed inside the hardest bone of the body - the temporal bone. The outer ear only concentrates sound waves and conducts them to internal structures. In the dense bone of the inner ear there are two extremely sensitive formations: the cochlea, the organ of hearing itself, and the membranous labyrinth inserted into it - one of the sources of nerve signals in the central nervous system, thanks to which the balance of the body is maintained. This article is devoted to the human ear. ABOUT hearing aid and hearing characteristics of animals - see BIRDS,
INSECTS ,
MAMMALS,
as well as articles on certain species animals.
ANATOMY OF THE EAR
Anatomically, the ear is divided into three parts: the outer, middle and inner ear.

Outer ear. The protruding part of the outer ear is called the auricle; it is based on semi-rigid supporting tissue - cartilage. The opening of the external auditory canal is located in the front of the auricle, and the passage itself is directed inward and slightly forward. The auricle concentrates sound vibrations and directs them to the external auditory opening. Earwax is a waxy secretion of the sebaceous and sulfur glands of the external auditory canal. Its function is to protect the skin of this passage from bacterial infection and foreign particles, such as insects, that may get into the ear. The amount of sulfur varies from person to person. A dense lump of earwax (cerumen plug) can lead to impaired sound conduction and hearing loss.
Middle ear, which includes the tympanic cavity and the auditory (Eustachian) tube, refers to the sound-conducting apparatus. A thin, flat membrane called the eardrum separates the inner end of the external auditory canal from the tympanic cavity, a flattened, rectangular space filled with air. In this cavity of the middle ear there is a chain of three movably articulated miniature bones (ossicles), which transmit vibrations from the eardrum to the inner ear. According to their shape, the bones are called the malleus, incus and stirrup. The malleus, with its handle, is attached to the center of the eardrum by means of ligaments, and its head is connected to the incus, which, in turn, is attached to the stapes. The base of the stapes is inserted into the oval window, an opening in the bony wall of the inner ear. Tiny muscles help transmit sound by regulating the movement of these ossicles. The optimal condition for vibration of the eardrum is equal air pressure on both sides. This happens due to the fact that the tympanic cavity communicates with the external environment through the nasopharynx and the auditory tube, which opens into the lower anterior corner of the cavity. When swallowing and yawning, air enters the tube, and from there into the tympanic cavity, which allows it to maintain pressure equal to atmospheric pressure. The facial nerve passes through the middle ear cavity on its way to the facial muscles. It is enclosed in a bony canal above the inner wall of the tympanic cavity, goes back, down and exits under the ear. Inside the ear it gives a twig, the so-called. drum string. Its name is due to the fact that it runs along the inner surface of the eardrum. Then the nerve goes forward and down under the lower jaw, where branches extend from it to the taste buds of the tongue. The mastoid process is located posterior to the external auditory canal and the tympanic cavity. The process contains bone cells various shapes and quantities filled with air. All cells communicate with a central space known as the cave (antrum), which in turn communicates with the cavity of the middle ear.
Inner ear. The bony cavity of the inner ear, containing a large number of chambers and passages between them, is called the labyrinth. It consists of two parts: the bony labyrinth and the membranous labyrinth. The bony labyrinth is a series of cavities located in the dense part of the temporal bone; three components are distinguished in it: semicircular canals - one of the sources of nerve impulses reflecting the position of the body in space; vestibule; and the cochlea - the organ of hearing. The membranous labyrinth is enclosed within the bony labyrinth. It is filled with a fluid, endolymph, and is surrounded by another fluid, perilymph, which separates it from the bony labyrinth. The membranous labyrinth, like the bony labyrinth, consists of three main parts. The first corresponds in configuration to the three semicircular canals. The second divides the bony vestibule into two sections: the utricle and the saccule. The elongated third part forms the middle (cochlear) scala (spiral canal), repeating the bends of the cochlea (see section COCHALE below).
Semicircular canals. There are only six of them - three in each ear. They have an arched shape and begin and end in the uterus. The three semicircular canals of each ear are located at right angles to each other, one horizontally and two vertically. Each channel has an extension at one end - an ampoule. The six channels are arranged in such a way that for each there is an opposite channel in the same plane, but in a different ear, but their ampoules are located at mutually opposite ends.
Cochlea and organ of Corti. The name of the snail is determined by its spirally convoluted shape. This is a bone canal that forms two and a half turns of a spiral and is filled with fluid. Inside, on one wall of the spiral canal along its entire length there is a bony protrusion. Two flat membranes extend from this protrusion to the opposite wall so that the cochlea is divided along its entire length into three parallel channels. The two external ones are called the scala vestibuli and the scala tympani; they communicate with each other at the apex of the cochlea. Central, so-called the spiral canal of the cochlea ends blindly, and its beginning communicates with the sac. The spiral canal is filled with endolymph, the scala vestibule and scala tympani are filled with perilymph. Perilymph has a high concentration of sodium ions, while endolymph has a high concentration of potassium ions. The most important function endolymph, which is positively charged in relation to perilymph, is the creation of an electrical potential on the membrane separating them, which provides energy for the process of amplifying incoming sound signals.

Equilibrium.
Balance when moving. When the head turns in one of three planes corresponding to the location of the semicircular canals, the fluid in one of the canals moves towards the ampulla, and in the opposite (in the other ear) - away from the ampulla. A change in fluid pressure in the ampoule stimulates a group of sensory cells connected to nerve fibers, which, in turn, transmit signals about changes in body position to the brain. Vertical channels are stimulated by jumping or falling, and horizontal channels are stimulated by turning or spinning.
Balance at rest. The semicircular canals are involved in maintaining the balance of the body during movement, and the utricle and sac are sensitive to the static position of the head relative to gravity. Inside the sac and utricle are small groups of cells with short, protruding hairs; above them there is a gelatinous layer containing crystals of calcium carbonate - otoliths. The gelatinous layer (otolithic membrane) is quite heavy and rests only on hairs. In one position of the head, some hairs bend, in another, others. Information from these hair cells travels to the brain through the vestibular nerve (vestibular branch of the vestibulocochlear nerve).
Reflex (automatic) maintenance of balance. Everyday experience shows that a person does not think about maintaining balance or about his position relative to gravity. This happens because the corresponding adaptive reactions are automatic. A number of complex reflexes that control the tone of skeletal muscles are associated with the semicircular canals and the uterus. Reflexes are closed at the level of brain stem structures or in spinal cord, i.e. without the participation of higher centers and consciousness (see REFLEX). Another set of reflexes connects signals coming from the semicircular canals with oculomotor reactions, due to which, when the eyes move, they automatically keep a certain area of ​​​​space in the field of vision.
EAR DISEASES
The ear and surrounding structures contain a variety of tissue types, each of which can serve as a source of disease; therefore ear diseases include wide range pathological conditions. Any disease of the skin, cartilage, bones, mucous membranes, nerves or blood vessels may be localized in or around the ear. Eczema and skin infections - quite frequent illnesses outer ear. The external auditory canal is especially susceptible to them due to the fact that it is dark, warm and moist. Eczema is difficult to treat. Its main symptoms are peeling and cracking of the skin, accompanied by itching, burning and sometimes discharge. Infectious inflammation external ear subjectively causes a lot of trouble, since the hard wall of the canal and the proximity of the bone cause compression of the irritated skin in the event of a boil or other inflammatory process; as a result, even a very small boil that would be barely noticeable in soft tissues, can be extremely painful in the ear. Fungal infections of the external auditory canal are also common.
Infectious diseases of the middle ear. The infection causes inflammation of the middle ear ( otitis media); it enters the tympanic cavity from the nasopharynx through the canal connecting them - the auditory tube. The eardrum becomes red, tense and painful. Pus may accumulate in the middle ear cavity. In severe cases, a myringotomy is performed, i.e. the eardrum is incised to allow drainage of pus; under the pressure of accumulated pus, it can rupture spontaneously. Usually, otitis media responds well to treatment with antibiotics, but sometimes the disease progresses and mastoiditis (inflammation of the mastoid process of the temporal bone), meningitis, brain abscess, or other severe infectious complications, which may require urgent surgical intervention. Acute infectious inflammation of the middle ear and mastoid process can become chronic, which, despite mild symptoms, continues to threaten the patient. The introduction of plastic drains and ventilation tubes into the cavity reduces the likelihood of relapse of an acute condition. The most important complication of middle ear diseases is hearing loss caused by impaired sound conduction. The patient appears fully recovered after treatment with penicillin or other antibiotics, but a small amount of fluid remains inside the tympanic cavity, and this is enough to cause hearing loss, accompanied by tension, fatigue and poor understanding of speech. This condition - secretory otitis media - can lead to a decrease in the child's performance at school. The paucity of symptoms does not allow a quick diagnosis, but treatment is simple - a small incision is made in the eardrum and fluid is removed from the cavity. Repeated infection in this area can lead to adhesive (adhesive) otitis with the formation of adhesions in the tympanic cavity or to partial destruction of the eardrum and auditory ossicles. In these cases, correction is carried out using surgical operations, united under the general name of tympanoplasty. A middle ear infection can also cause tinnitus. Tuberculosis and syphilis of the ear are almost always associated with the presence of a focus of the corresponding infection in the body. Ear cancer can occur in any part of the ear, but is rare. Sometimes develop benign tumors requiring surgical intervention. Meniere's disease is a disease of the inner ear, characterized by hearing loss, ringing in the ears and dizziness - from mild dizziness and unsteadiness of gait to severe attacks with complete loss of balance. Eyeballs make involuntary fast rhythmic movements (horizontal, less often vertical or circular), called nystagmus. Many, even quite severe cases, are amenable to therapeutic treatment; if it fails, they resort to surgical destruction of the labyrinth. Otosclerosis is a disease of the bone capsule of the labyrinth, which leads to a decrease in the mobility of the base of the stapes in the oval window of the inner ear and, as a consequence, to impaired sound conduction and hearing loss. In many cases, significant improvement in hearing is achieved through surgery.
EAR SURGERY
Ear surgery specializes in surgical treatment deformations, infectious processes in the ear and surrounding tissues and surgical treatment of deafness. The complexity and fragility of the structures of the inner ear delayed the development of ear surgery until the end of the 19th century, since most attempts at surgical intervention ended in failure. The era of modern ear surgery began in 1885, when German otolaryngologists G. Schwarze and A. Eisell proposed a carefully developed technique for draining and opening the mastoid air cells as a way to treat its chronic inflammation. Tympanoplasty. Since 1950 many have been developed surgical techniques restoration of damaged parts of the middle ear. Recent advances in this area have been made possible largely due to the advent of the operating microscope, which allows surgeons to perform delicate manipulations aimed at restoring the fragile structures of the middle ear. A damaged or scarred eardrum can be replaced by grafting connective tissue from the surface of the nearby temporalis muscle. If the damage extends to the bones of the inner ear, transplantation of the eardrum and the entire chain of auditory ossicles using cadaveric material is possible.
Stirrup prostheses. Deafness caused by impaired sound conduction may be associated with blockage of stapes vibrations in the oval window of the cochlea due to scar formation. In this case, sound vibrations do not reach the cochlear canal. For early stages process, a technique has been developed for stapes remobilization (destruction of scar tissue, replacement of the oval window membrane, or both) and fenestration (creation of a new opening in the cochlear canal). The development of prostheses to replace several or all of the ossicles of the tympanic cavity has simplified operations and significantly improved their results. A stapes prosthesis made of Teflon, tantalum or ceramic helps restore sound transmission from the eardrum to the cochlea.
Cochlear prostheses. In sensorineural (caused by impaired perception of sound) deafness, the hair cells of the organ of Corti are damaged or absent, i.e. sound vibrations are not converted into electrical impulses of the auditory nerve. If the auditory nerve is still functioning, hearing can be partially restored by implanting an electrode into the cochlea and directly stimulating the nerve fibers electric shock. Several devices have been developed that convert sounds picked up by an external microphone into electrical signals that are transmitted through the skin to the cochlea, causing irritation of nearby auditory nerve fibers. These nerve impulses are perceived by the brain as sound, similar to impulses from the hair cells of the organ of Corti. However, the sound quality is still low and even in best cases it is barely enough to partially understand speech.
Plastic surgery of the ear. Methods plastic surgery used to correct congenital or trauma-related ear deformities. For example, appearance If the outer ear has suffered multiple injuries, it can be restored by transplanting cartilage and skin from other parts of the body. Plastic surgery methods can also improve the appearance of patients with protruding ears.
see also DEAFNESS; RUMOR.

Collier's Encyclopedia. - Open Society. 2000 .

See what “EAR” is in other dictionaries:

Ah, plural ears, ears, cf. 1. Organ of hearing. External, middle, internal. (anat.). It's hard to hear in the left ear. I am deaf in one ear. Noise in ears. There is a ringing in the ear (see ringing). “I heard him speak with my own ears.” Pisemsky. “There’s a multilingual buzzing in my ears... ... Dictionary Ushakova

- (1) 1. The organ of hearing in humans and animals: [Ti bo Oleg swords sedition, and sows arrows on the ground. The stirrup steps into gold in the city of Tmutorokan. The same ringing heard the ancient great Yaroslav, and his son Vsevolozh Vladimir ears all morning... ... Dictionary-reference book "The Tale of Igor's Campaign"

EAR- (external) consists of the concha (auricula) and the external auditory canal (meatus auditorius externus); develops from a cushion surrounding the eardrum of the embryo, located initially at the level of the skin. In this education there arises... ... Great Medical Encyclopedia

The ear performs two main functions: the organ of hearing and the organ of balance. The organ of hearing is the main information system that takes part in the development of speech function, and therefore, human mental activity. There are external, middle, and inner ears.

External ear - auricle, external auditory canal

Middle ear – tympanic cavity, auditory tube, mastoid process

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

The outer and middle ears provide sound conduction, and the inner ear contains receptors for both the auditory and vestibular analyzers.

Outer ear. The auricle is a curved plate of elastic cartilage, covered on both sides by 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 cartilage and contains fatty tissue. IN auricle There are helix (helix), antihelix (anthelix), tragus (tragus), antitragus (antitragus). The helix is ​​part of the external auditory canal. The external auditory canal in an adult consists of two sections: the external - membranous-cartilaginous, equipped with hairs, sebaceous glands and their modifications - earwax glands (1/3); internal – bone, not containing hair and glands (2/3).

The topographic-anatomical relationships of the parts of the auditory canal are of clinical importance. Front wall – borders on the articular capsule of the lower jaw (important for external otitis and injuries). From below – The parotid gland is adjacent to the cartilaginous part. The anterior and lower walls are pierced by vertical slits (Santorini slits) in an amount from 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 the mastoid process. The descending part of the facial nerve passes deep into this wall (radical surgery). Upper – borders on the middle cranial fossa. Superior posterior – is the anterior wall of the antrum. Its omission indicates purulent inflammation cells of the mastoid process.

The outer ear is supplied with blood from the external carotid artery due to the superficial temporal (a. temporalis superficialis), occipital (a. occipitalis), posterior auricular and deep auricular arteries (a. auricularis posterior et profunda). Venous outflow is carried out into the superficial temporal (v. temporalis superficialis), external jugular (v. jugularis ext.) and jaw (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 nerves, as well as from the auricular nerve from the upper cervical plexus. Due to the vagal reflex with sulfur plugs and foreign bodies, cardialgic phenomena and cough are possible.

The boundary between the outer and middle ear is the eardrum. The diameter of the eardrum (Fig. 1) is approximately 9 mm, thickness 0.1 mm. The eardrum serves as one of the walls of the middle ear, tilted forward and downward. 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 membrane 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 eardrum is low-elastic and can rupture under sudden 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 the b/p there are two parts: tense (pars tensa) and loose (pars flaccida). The tense part is inserted into the bone tympanic ring and has a middle fibrous layer. Loose or relaxed, it is attached to a small notch of the lower edge of the squama of the temporal bone; this part does not have a fibrous layer.

On otoscopic examination, the color of the b/p is pearlescent or pearl-gray with a slight sheen. For the convenience of clinical otoscopy, the b/p is mentally divided into four segments (anterosuperior, anterioinferior, posterosuperior, posteroinferior) by two lines: one is a continuation of the handle of the hammer to the lower edge of the b/p, and the second runs perpendicular to the first through the navel of the 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 in the back passes into the mucous membrane of the mastoid cells, and in front into the mucous membrane of the auditory tube. It is represented by 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 columnar epithelium, the movement of the cilia is directed towards the nasopharynx.

External (membranous) The wall of the tympanic cavity over a larger extent is formed by the inner surface of the ear canal, and above it - by the upper wall of the bony 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 window of the vestibule, closed by the base of the stapes. Above the window of the vestibule there is a protrusion of the facial canal, below the window of the vestibule there is a round-shaped elevation called the promontory (promontorium), corresponding to the protrusion of the first curl of the cochlea. Below and posterior to the promontory there is a fenestra cochlea, closed by a secondary b/p.

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

Lower (jugular) wall - formed by the petrous 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 in the jugular wall there are numerous small cells that separate the bulb of the jugular vein from the tympanic cavity; sometimes dehiscence is observed in this wall, which facilitates the penetration of infection.

Anterior (sleepy) the wall in the upper half is occupied by the tympanic orifice of the auditory tube. Its lower part borders the canal of the internal carotid artery. Above the auditory tube is the hemicanal of the tensor tympani muscle (m. tensoris tympani). The bone plate separating the internal carotid artery from the mucous membrane of the tympanic cavity is penetrated by thin tubules and often has dehiscence.

Posterior (mastoid) the wall borders the mastoid process. In the upper section of its back wall there is an entrance to the cave. The canal of the facial nerve passes deep into the posterior wall; the stapedius muscle begins from this wall.

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

The auditory ossicles, which are involved in sound conduction, are located in the tympanic cavity. The auditory ossicles - malleus, incus, stapes - are a closely connected chain located between the tympanic membrane and the window of the vestibule. And through the window of the vestibule, the auditory ossicles transmit sound waves to the fluid of the inner ear.

Hammer – it distinguishes between a head, a neck, a short process and a handle. The handle of the malleus is fused with the anvil, a short process protrudes outward from the upper portion of the anvil, and the head articulates with the body of the incus.

Anvil – it has a body and two legs: short and long. A short leg is placed at the entrance to the cave. The long leg connects to the stirrup.

Stirrup – it distinguishes head, front and rear legs, connected to each other by a plate (base). The base covers the window of the vestibule and is strengthened with the window using an annular ligament, due to which the stapes is movable. And this ensures the constant transmission of sound waves into the fluid of the inner ear.

Middle ear muscles. Tensor tympani muscle (m. tensor tympani), innervated trigeminal nerve. The stapes 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 and contract reflexively, protecting the inner ear from excessive amplitude of sound vibrations. Sensitive innervation of the tympanic cavity is provided by the tympanic plexus.

The auditory or pharyngotympanic tube connects the tympanic cavity to 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 lateral 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 the tubal cartilage, behind which there is a depression - the Rosenmüllerian fossa. The mucous membrane of the tube is covered with multinucleated ciliated epithelium (the movement of the cilia is directed from the tympanic cavity to the nasopharynx).

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

The blood supply to the middle ear is carried out by branches of the external and internal carotid arteries. Venous blood flows into the pharyngeal plexus, the bulb of the jugular vein and the 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 topographic-anatomical proximity facial nerve Let us trace its course to the formations of the temporal bone. The trunk of the facial nerve is formed in the region of the cerebellopontine triangle and is directed together with the VIII cranial nerve into the internal auditory canal. In the thickness of the petrous part of the temporal bone, near the labyrinth, its petrous ganglion is located. In this area, the greater petrosal nerve branches off from the trunk of the facial nerve, containing parasympathetic fibers for the lacrimal gland. Next, 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 genu). The bony (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 is directed steeply downward (second genu) and exits the temporal bone through the stylomastoid foramen (foramen stylomastoideum), breaking up in a fan shape into separate branches, the so-called crow's foot (pes anserinus), innervating the facial muscles. At the level of the second genu, the stapedius departs from the facial nerve, and more caudally, almost at the exit of the main trunk from the stylomastoid foramen, the chorda tympani. The latter passes in a separate tubule, penetrates the tympanic cavity, moving anteriorly between the long leg of the incus and the handle of the malleus, and leaves the tympanic cavity through the petrotympanic (Glaserian) fissure (fissura petrotympanical).

Inner ear lies in the thickness of the pyramid of the temporal bone, two parts are distinguished in it: the bony and membranous labyrinth. The bony labyrinth includes the vestibule, cochlea, and three bony semicircular canals. 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 floor of the internal auditory canal. There are two depressions on it - spherical and elliptical, separated from each other by a vertically running ridge of the vestibule (crista vestibule).

The bony semicircular canals are located in the posteroinferior part of the bone labyrinth in three mutually perpendicular planes. There are lateral, anterior and posterior semicircular canals. These are arched curved tubes in each of which there are two ends or bone legs: expanded or ampullary and unexpanded 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 section of the vestibule with a canal that bends spirally and forms 2.5 turns, which is why it is called the spiral canal of the cochlea. There is a base and apex of the cochlea. The spiral channel winds around a cone-shaped bone shaft and ends blindly at the apex of the pyramid. The bone plate does not reach the opposite outer wall of the bony cochlea. The continuation of the spiral bone plate is the tympanic plate of the cochlear duct (main 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 located 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, the scala vestibule, and the lower one, the scala tympani. Both scalae contain perilymph and communicate with each other through an opening at the apex of the cochlea (helicotrema). The scala vestibule borders the window of the vestibule, closed by the base of the stapes; the scala tympani borders the window of the cochlea, 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 soft 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 vestibule - the vestibular plate of the cochlear duct, also extends from the free edge of the bony plate at an angle of 45º. The outer wall of the cochlear duct is part of the outer bony wall of the cochlear canal. On the spiral ligament adjacent to this wall there is a vascular strip. The tympanic wall of the cochlear duct consists of radial fibers arranged in the form of strings. Their number reaches 15,000 - 25,000, their length at the base of the cochlea is 80 microns, at the apex - 500 microns.

The spiral organ (Corti) is located on the tympanic wall of the cochlear duct and consists of highly differentiated hair cells, supporting columnar cells 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 directed through tunnels to the spiral ganglion at the base of the spiral bone plate. There are up to 30,000 ganglion cells in total. The axons of these ganglion cells connect in the internal auditory canal to the cochlear nerve. Above the spiral organ is a covering membrane, which begins near the origin of the vestibular wall of the cochlear duct and covers the entire spiral organ in the form of a canopy. Stereocilia of hair cells penetrate the integumentary membrane, which plays a special role in the process of sound reception.

The internal auditory canal begins with the internal auditory opening, located on the posterior edge of the pyramid, and ends with the bottom of the internal auditory canal. It contains the periocochlear nerve (VIII), consisting of the superior vestibular root and the inferior cochlear root. Located above it facial nerve and next to it is the intermediate nerve.