The middle ear is a component of the ear. Occupies the space between the external auditory organ and the eardrum. Its structure involves numerous elements that have certain features and functions.
Structural features
The middle ear consists of several important elements. Each of these components has structural features.
Tympanic cavity
This is the middle part of the ear, very vulnerable, often subject to inflammatory diseases. It is located behind the eardrum, not reaching inner ear. Its surface is covered with a thin mucous membrane. It has the shape of a prism with four irregular faces and is filled with air inside. Consists of several walls:
- The outer wall with a membranous structure is formed internal part eardrum, as well as the bone of the auditory canal.
- The inner wall at the top has a recess in which the window of the vestibule is located. It is a small oval hole, which is covered by the lower surface of the stapes. Below it there is a cape along which a furrow runs. Behind it is a funnel-shaped dimple in which the cochlear window is placed. From above it is limited by a bone ridge. Above the window of the cochlea there is a tympanic sinus, which is a small depression.
- The upper wall, which is called the tegmental wall, as it is formed by hard bone substance and protects it. The deepest part of the cavity is called the dome. This wall is necessary to separate the tympanic cavity from the walls of the skull.
- The lower wall is jugular, as it participates in the creation of the jugular fossa. It has an uneven surface because it contains drum cells necessary for air circulation.
- The posterior mastoid wall contains an opening that leads into the mastoid cave.
- The anterior wall has a bone structure and is formed by substance from the carotid artery canal. Therefore, this wall is called the carotid wall.
Conventionally, the tympanic cavity is divided into 3 sections. The lower one is formed by the lower wall of the tympanic cavity. Average is most of, the space between the upper and lower boundaries. Upper section– part of the cavity corresponding to its upper boundary.
Auditory ossicles
They are located in the tympanic cavity and have important, since without them sound perception would be impossible. These are the hammer, anvil and stirrup.
Their name comes from the corresponding shape. They are very small in size and are lined on the outside with mucous membrane.
These elements connect to each other to form real joints. They have limited mobility, but allow you to change the position of the elements. They are connected to each other as follows:
- The hammer has a rounded head connected to the handle.
- The anvil has a rather massive body, as well as 2 processes. One of them is short, rests against the hole, and the second is long, directed towards the handle of the hammer, thickened at the end.
- The stirrup includes a small head, covered on top with articular cartilage, which serves to articulate the incus and 2 legs - one straight and the other more curved. These legs are attached to the oval plate contained in the fenestra vestibule.
The main function of these elements is the transmission of sound impulses from the membrane to the oval window of the vestibule. In addition, these vibrations are amplified, which makes it possible to transmit them directly to the perilymph of the inner ear. This occurs due to the fact that the auditory ossicles are articulated in a lever manner. In addition, the size of the stapes is many times smaller than the eardrum. Therefore, even small sound waves make it possible to perceive sounds.
Muscles
There are also 2 muscles in the middle ear - they are the smallest in human body. The muscle bellies are located in the secondary cavities. One serves to tension the eardrum and is attached to the handle of the hammer. The second is called the stirrup and is attached to the head of the stapes.
These muscles are necessary to maintain position auditory ossicles, regulate their movements. This provides the ability to perceive sounds of varying strengths.
Eustachian tube
The middle ear connects to the nasal cavity through the Eustachian tube. It is a small canal, about 3-4 cm long. C inside it is covered with a mucous membrane, on the surface of which there is ciliated epithelium. The movement of its cilia is directed towards the nasopharynx.
Conventionally divided into 2 parts. The one that is adjacent to the ear cavity has walls with a bone structure. And the part adjacent to the nasopharynx has cartilaginous walls. IN in good condition the walls are adjacent to each other, but when the jaw moves, they diverge in different directions. Thanks to this, air flows freely from the nasopharynx into the hearing organ, ensuring equal pressure within the organ.
Due to its close proximity to the nasopharynx, the Eustachian tube is susceptible to inflammatory processes, since infection can easily enter it from the nose. Its patency may be impaired due to colds.
In this case, the person will experience congestion, which brings some discomfort. To deal with it, you can do the following:
- Examine the ear. An unpleasant symptom may be caused ear plug. You can remove it yourself. To do this, drop a few drops of peroxide into the ear canal. After 10-15 minutes, the sulfur will soften, so it can be easily removed.
- Move your lower jaw. This method helps with mild congestion. Needs to be extended lower jaw forward and move it from side to side.
- Apply the Valsalva technique. Suitable in cases where ear congestion does not go away for a long time. It is necessary to close your ears and nostrils and take a deep breath. You should try to exhale it with your nose closed. The procedure should be carried out very carefully, as during it the arterial pressure and increase your heart rate.
- Use Toynbee's method. You need to fill your mouth with water, close your ears and nostrils, and take a sip.
The Eustachian tube is very important because it maintains normal pressure in the ear. And when it is blocked by various reasons this pressure is disturbed, the patient complains of tinnitus.
If after carrying out the above manipulations the symptom does not go away, you should consult a doctor. Otherwise, complications may develop.
Mastoid
It's small bone formation, convex above the surface and shaped like a papilla. Located behind the ear. It is filled with numerous cavities - cells connected to each other by narrow slits. The mastoid process is necessary to improve the acoustic properties of the ear.
Main functions
You can select following functions middle ear:
- Sound conduction. With its help, sound is sent to the middle ear. The outer part picks up sound vibrations, then they pass through the auditory canal, reaching the membrane. This leads to its vibration, which affects the auditory ossicles. Through them, vibrations are transmitted to the inner ear through a special membrane.
- Even distribution of pressure in the ear. When the atmospheric pressure is very different from that in the middle ear, it is equalized through the Eustachian tube. Therefore, when flying or when immersed in water, the ears temporarily become blocked, as they adapt to new pressure conditions.
- Safety function. middle part The ear is equipped with special muscles that protect the organ from injury. With very strong sounds, these muscles reduce the mobility of the auditory ossicles to a minimum level. Therefore, the membranes do not rupture. However, if the strong sounds are very sharp and sudden, the muscles may not have time to perform their functions. Therefore, it is important to protect yourself from such situations, otherwise you may partially or completely lose your hearing.
Thus, the middle ear performs very important functions and is an integral part auditory organ. But it is very sensitive, so it should be protected from negative impacts . Otherwise, various diseases may appear that lead to hearing impairment.
Not everyone knows what otitis media is. This is a disease that affects the human ear. It lies in acute inflammation tissues that make up this important sensory organ. Thousands of people get sick with otitis media every year. different ages. And it is well known that otitis media cannot be called a harmless disease.
What is otitis media
To understand the principle of the occurrence of otitis, you need to remember what it is - the ear, what it is needed for and how it works. In fact, the ear is far from just the pinna, as some might think. The ear has a hidden inside complex system on transformation sound waves in a form that is convenient for perception by the human brain. However, picking up sounds is not the only function of the ears. They also perform a vestibular function and serve as an organ that allows a person to maintain balance.
The three main sections of the ear are the middle, outer and inner. The outer ear is the pinna itself, as well as the auditory canal leading to the eardrum. Behind the eardrum is an air-filled tympanic cavity containing three auditory ossicles, the purpose of which is to transmit and amplify sound vibrations. This area makes up the middle ear. From the middle ear vibrations enter special area, which is located in temporal bone and it's called a labyrinth. It contains the organ of Corti - a cluster of nerve receptors that convert vibrations into nerve impulses. This area is called the inner ear. Also noteworthy is the Eustachian tube, the entrance of which is located behind palatine tonsils and which leads into the tympanic cavity. Its purpose is to ventilate the tympanic cavity, as well as to adjust the pressure in the tympanic cavity atmospheric pressure. The Eustachian tube is usually referred to as the middle ear.
It should be noted that otitis media can affect all three ear sections. Accordingly, if the disease affects the outer ear, then we talk about external otitis, if it is middle, then about otitis media, if the inner ear, then about internal. As a rule, we are talking only about one-sided lesions, however, with otitis media caused by infections of the upper respiratory tract, the disease can develop on both sides of the head.
Ear otitis is also divided into three types depending on the cause - viral, bacterial or traumatic. External otitis can also be fungal. Most common bacterial form diseases.
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How does the ear work?Otitis externa - symptoms, treatment
Otitis externa occurs as a result of infection of the surface of the skin auricle bacteria or fungi. According to statistics, approximately 10% of the world's population has suffered from external otitis at least once in their lives.
Factors contributing to otitis in adults are:
- hypothermia of the auricle, for example, during walks in the cold;
- mechanical damage to the auricle;
- removal of wax from the ear canal;
- entry of water, especially dirty water, into the ear canal.
Bacteria and fungi “love” the ear canal because it is damp, dark and quite humid. It provides an ideal place for their breeding. And, probably, everyone would have otitis externa, if not for such a protective feature of the body as the formation of earwax. Yes, earwax is not at all a useless substance that clogs the ear canal, as many people think. It performs important bactericidal functions, and therefore its removal from the ear canal can lead to otitis media. The only exception is when too much sulfur is released and it affects the perception of sounds.
Inflammation of the external auditory canal usually refers to a type skin diseases– dermatitis, candidiasis, furunculosis. Accordingly, the disease is caused by bacteria, streptococci and staphylococci, fungi of the genus Candida. In the case of furunculosis, inflammation occurs sebaceous glands. The main symptom of external otitis is, as a rule, pain, especially aggravated by pressure. Elevated temperature with external otitis it usually does not occur. Hearing loss rarely occurs with external otitis, except in cases where the process affects the eardrum or the ear canal is completely closed with pus. However, after recovery from otitis media, hearing is completely restored.
Diagnosis of external otitis in adults is quite simple. As a rule, a visual examination by a doctor is sufficient. A more detailed method of diagnosing otitis involves the use of an otoscope, a device that allows you to see the far end of the ear canal and the eardrum. Treatment of otitis media consists of eliminating the cause of ear inflammation. When treating otitis externa in adults, antibiotics or antifungal drugs. The type of antibacterial therapy should be determined by the doctor. As a rule, in the case of external otitis, they are used ear drops, not pills. When external tissues of the auricle not located in the area of the auditory canal are affected, ointments are used. Frequent complication external otitis – the transition of the inflammatory process to the middle ear through the eardrum.
Otitis media
Otitis media is an inflammation of the middle part of the hearing organ. This kind of ear inflammation is one of the most common diseases on Earth. Hundreds of millions of people suffer from ear infections every year. According to various data, from 25% to 60% of people have suffered from otitis media at least once in their lives.
Causes
In most cases inflammatory process the middle ear is not primary disease. As a rule, it is a complication of external otitis or infectious diseases of the upper respiratory tract - tonsillitis, rhinitis, sinusitis, as well as acute viral diseases- flu, scarlet fever.
How does an infection from the respiratory tract get into the ear? The fact is that she has a direct path there - this is the Eustachian tube. When you have respiratory symptoms such as sneezing or coughing, particles of mucus or phlegm may be pushed up the tube into your ear. In this case, both inflammation of the Eustachian tube itself (eustachitis) and inflammation of the middle ear can occur. When the Eustachian tube is blocked in the tympanic cavity, which is deprived of ventilation, stagnation processes can occur and fluid can accumulate, which leads to the proliferation of bacteria and the occurrence of disease.
Mastoiditis can also be the cause of otitis media, allergic reactions, causing swelling mucous membranes.
Otitis ear has several varieties. First of all, a distinction is made between chronic and acute otitis media. According to the degree of development, otitis of the middle ear is divided into exudative, purulent and catarrhal. Exudative otitis media is characterized by the accumulation of fluid in the tympanic cavity. At purulent otitis The appearance of pus and its accumulation is noted in the middle ear.
Otitis media, symptoms in adults
Symptoms in adults primarily include ear pain. Pain with otitis media can be acute or shooting. Sometimes pain can be felt in the temple or crown area, it can pulsate, subside or intensify. With exudative otitis media, there may be a sensation of water splashing in the ear. Sometimes there is ear congestion, as well as a feeling of hearing one's own voice (autophony) or just a vague noise in the ear. Tissue swelling, hearing loss, fever, and headaches are often observed. However, an increase in temperature is often not a symptom of otitis media, but only a symptom of the infectious disease that caused it - acute respiratory infections, acute respiratory viral infections or influenza.
The most complex course is observed in the purulent form of otitis media. IN in this case The main symptom of otitis media is the discharge of pus. The tympanic cavity is filled with pus, and the body temperature rises to +38-39ºС. Pus can thin the surface of the eardrum and form a hole in it through which it leaks out. However, this process is generally beneficial, since the pressure in the cavity drops, and as a result the pain becomes less acute. The process of draining pus takes about a week. From this moment, the temperature drops to subfebrile levels and wound healing begins. The total duration of the disease is 2-3 weeks with proper and timely treatment.
The chronic form of the disease is characterized by sluggish infectious process, in which there are seasonal surges, during which the disease becomes acute.
Diagnostics
If you have suspicious symptoms, you should consult a doctor. Diagnosis is carried out by an otolaryngologist. The following diagnostic sign can be used for this. If an otolaryngologist’s patient puffs out his cheeks, then the immobility of the membrane indicates that air does not enter the tympanic cavity from the nasopharynx and, therefore, the Eustachian tube is blocked. Inspection of the eardrum is carried out using an optical device - an otoscope also helps to identify some characteristic features, for example, protrusion of the eardrum and its redness. A blood test can also be used for diagnosis, CT scan, radiography.
Treatment
How to treat the disease? Treatment of otitis media is quite complex compared to treatment of external otitis. However, in most cases conservative treatment is used. First of all, in case of acute otitis media, it makes no sense to instill ear drops with antibacterial drugs, since they will not reach the site of inflammation. However, for inflammation of the middle ear, the focus of which is directly adjacent to the eardrum, anti-inflammatory and analgesic drops can be instilled into the ear. They can be absorbed by the eardrum, and the substance will enter the region of the middle part of the organ of hearing, into the tympanic cavity.
Antibiotics are the main method of treating otitis media in adults and children. Typically, medications are taken in tablet form. However, if the eardrum has ruptured, antibiotic ear drops can also be used. A course of antibiotics must be prescribed by a doctor. He also chooses the type of antibiotics, since many of them have an ototoxic effect. Their use can cause irreversible hearing loss.
The greatest effectiveness for otitis media of the middle ear was demonstrated by a course of treatment with antibiotics penicillin series, amoxicillins, as well as cephalosporins or macrolides. However, cephalosporin has an ototoxic effect, so it is not recommended to inject it directly into the ear through a catheter or instill it into the ear canal in case of damage to the eardrum. Can be used for therapy antiseptics, such as miramistin.
When treating otitis media, it is often necessary to use painkillers. To remove pain syndrome for diseases of the middle part of the hearing organ, drops with painkillers, for example, lidocaine, are used.
In case of membrane perforation, scar stimulants are used to speed up its healing. These include ordinary iodine solution and silver nitrate 40%.
Glucocorticoids (prednisolone, dexomethasone), as well as non-steroidal anti-inflammatory drugs, can be used as anti-inflammatory drugs and agents that can relieve swelling. In the presence of allergic processes or with exudative otitis, they are used antihistamines, for example, suparastin or tavegil.
Also, for exudative otitis media, medications are taken to thin the exudate, for example, carbocisteine. There are also complex preparations, having several types of action, for example, Otipax, Otinum, Otofa, Sofradex. At purulent discharge You should regularly clean the ear canal of pus and rinse it with a weak stream of water.
Is it possible to warm your ear? It depends on the type of disease. In some cases, heat can speed up healing, while in others, on the contrary, it can aggravate the disease. In the purulent form of middle ear disease, heat is contraindicated, and in the catarrhal stage, heat promotes blood flow to the affected area and speeds up the patient’s recovery. Also, warmth is one of the effective ways reducing pain from otitis media. However, only a doctor can give permission to use heat; self-medication is unacceptable. If heat is contraindicated, it can be replaced with physiotherapeutic procedures (UHF, electrophoresis).
Often resort to surgical method treatment of the middle ear, especially in the case of a purulent variant of the disease and its rapid development, threatening severe complications. This operation is called paracentesis and is aimed at removing pus from the tympanic cavity. For mastoiditis, surgery can also be performed to drain the internal areas of the mastoid process.
Special catheters are also used to blow and clean the Eustachian tube. Medicines can also be administered through them.
Folk remedies for the treatment of middle ear inflammation in adults can only be used in relatively mild forms of the disease and with the permission of the attending physician. Here are some recipes suitable for treating otitis media.
Cotton wool is moistened with propolis infusion and inserted into the area of the external auditory canal. This composition has wound healing and antimicrobial properties. The tampon must be changed several times a day. Plantain juice, instilled into the ear in the amount of 2-3 drops per day, has a similar effect. To get rid of infections of the nasopharynx and larynx, which provoke middle ear infections, you can use rinses based on chamomile, sage, and St. John's wort.
Complications
With proper therapy, otitis media can go away without leaving any long-term consequences. However, inflammation of the middle ear can cause several types of complications. First of all, the infection can spread to inner ear and cause internal otitis - labyrinthitis. It can also cause permanent or transient hearing loss or complete deafness in one ear.
Perforation of the eardrum also leads to hearing loss. Although, contrary to popular belief, the membrane can become overgrown, even after it is overgrown, hearing sensitivity will be permanently reduced.
Mastoiditis is accompanied acute pain in the parotid space. It is also dangerous due to its complications - the breakthrough of pus on the membranes of the brain with the appearance of meningitis or in the neck area.
Labyrinthitis
Labyrinthitis is an inflammation of the inner ear. Of all types of otitis, labyrinthitis represents greatest danger. With inner ear inflammation, typical symptoms include hearing loss, vestibular disturbances and pain. Treatment of internal otitis is carried out only with antibiotics, no folk remedies in this case will not help.
Labyrinthitis is dangerous due to hearing loss as a result of the death of the auditory nerve. Also, with internal otitis, complications such as brain abscess are possible, which can lead to death.
Otitis ear in children
Otitis media in adults is much less common than this disease in children. This is due, firstly, to more weak immunity child's body. Therefore, children are more likely to have infectious diseases of the upper respiratory tract. In addition, the structural features auditory tube in children they contribute to stagnant processes in it. It has a straight profile, and the expanded lumen at its entrance facilitates the entry of mucus and even pieces of food or vomit (in infants).
Thorough treatment of otitis media childhood very important. If carried out incorrect treatment, then the disease can become chronic and make itself felt already in adulthood with chronic outbreaks. In addition, if otitis media is not cured in infancy, this may result in partial hearing loss, and this, in turn, leads to a delay mental development child.
Prevention of otitis media
Prevention includes preventing situations such as hypothermia of the body, primarily the ear area, getting dirty water into the ear canal area. Needs timely treatment inflammatory diseases upper respiratory tract, such as sinusitis, sinusitis, and pharyngitis. It is recommended to use a cap while swimming, and after being in the water, you should completely clear the ear canal of water. During the cold and damp seasons, it is recommended to wear a hat when going outside.
Table of contents of the topic "Anatomy of the ear":1. Vestibulocochlear organ, organum vestibulocochleare. The structure of the balance organ (pre-cochlear organ).
2. Embryogenesis of the organ of hearing and gravity (balance) in humans.
3. External ear, auris externa. Auricle, auricula. External auditory canal, meatus acusticus externus.
4. Eardrum, membrana tympani. Vessels and nerves of the external ear. Blood supply to the external ear.
5.
6. Auditory ossicles: Hammer, malleus; Anvil, incus; Stirrup, stapes. Functions of the bones.
7. Muscle tensor tympani, m. tensor tympani. Stapedius muscle, m. stapedius Functions of the muscles of the middle ear.
8. Auditory tube, or Eustachian tube, tuba auditiva. Vessels and nerves of the middle ear. Blood supply to the middle ear.
9. Inner ear, labyrinth. Bone labyrinth, labyrinthus osseus. vestibule, vestibulum.
10. Bone semicircular canals, canales semicirculares ossei. Snail, cochlea.
11. Membranous labyrinth, labyrinthus membranaceus.
12. Structure of the auditory analyzer. Spiral organ, organon spirale. Helmholtz's theory.
13. Vessels of the inner ear (labyrinth). Blood supply to the inner ear (labyrinth).
Middle ear, auris media. Tympanic cavity, cavitas tympanica. Walls of the tympanic cavity.
Middle ear, auris media, comprises tympanic cavity And auditory tube connecting the tympanic cavity with the nasopharynx.
Tympanic cavity, cavitas tympanica, lies at the base of the pyramid of the temporal bone between the outer ear canal and the labyrinth (inner ear). It contains a chain of three small bones that transmit sound vibrations from the eardrum to the labyrinth.
Tympanic cavity has a very small size (volume about 1 cm 3) and resembles a tambourine placed on its edge, strongly inclined towards the external auditory canal. There are six walls in the tympanic cavity:
1. Lateral wall of the tympanic cavity, paries membranaceus, formed by the eardrum and the bony plate of the external auditory canal. The upper dome-shaped expanded part of the tympanic cavity, recessus membranae tympani superior, contains two auditory ossicles; the head of the malleus and the incus. In case of illness pathological changes The middle ear is most pronounced in this recessus.
2. Medial wall of the tympanic cavity adjacent to the labyrinth, and therefore is called labyrinthine, paries labyrinthicus. It has two windows: round, snail window - fenestra cochleae, leading into the cochlea and tightened membrana tympani secundaria, And oval, window of the vestibule - fenestra vestibuli, opening in vestibulum labyrinthi. The base of the third auditory ossicle, the stapes, is inserted into the last hole.
3. Posterior wall of the tympanic cavity, paries mastoideus, carries eminence, eminentia pyramidalis, for premises m. stapedius. Recessus membranae tympani superior continues posteriorly into the mastoid cave, antrum mastoideum, where the airways open cells of the latter, cellulae mastoideae.
Antrum mastoideum is a small cavity protruding towards the mastoid process, from the outer surface of which it is separated by a layer of bone bordering the posterior wall of the auditory canal immediately behind the spina suprameatica, where the cave is usually opened during suppuration in the mastoid process.
4. Anterior wall of the tympanic cavity is called paries caroticus, since the inner one is close to it carotid artery. At the top of this wall is internal opening of the auditory tube, ostium tympanicum tubae auditivae, which in newborns and children early age gapes widely, which explains the frequent penetration of infection from the nasopharynx into the middle ear cavity and further into the skull.
Middle ear is a system of air cavities in the thickness of the temporal bone and consists of the tympanic cavity, the auditory tube and the mastoid process with its bone cells (Fig. 3.)
Rice. 3. Middle ear cavities:
1 - auditory tube;
2- tympanic cavity;
3- cave;
4 - cells of the mastoid process
Tympanic cavity is the central part of this system and is a narrow space in the thickness of the temporal bone with a volume of about 1 cm 3. There are six walls in the tympanic cavity. Outer wall along most of its length is the eardrum. The remaining walls are bone. Inner wall separates the tympanic cavity from the inner ear. There are two openings in this wall called windows: oval, or window vestibule(long diameter 3-4 mm) and round, or cochlear window (diameter 1-2 mm). IN oval window the footplate of the stapes is inserted, as if into a frame, attached to the edges of the oval window by means of annular ligament. The round window is covered with an elastic thin membrane, which is called secondary tympanic membrane. Upper wall, or roof of the tympanic cavity, separates
tympanic cavity from the cranial cavity. Bottom wall borders on a large blood vessel - the bulb jugular vein. IN back wall below there is an opening connecting the tympanic cavity with the mastoid cave.
The upper and lower walls of the tympanic cavity are often very thin, and often, especially in early childhood, there are holes in these walls. Then the mucous membrane of the tympanic cavity is adjacent directly to the meninges or to the bulb of the jugular vein, which poses a significant danger in the sense of the possible transition of the inflammatory process from the tympanic cavity to the meninges or to the walls of the jugular vein. In the thickness of the inner and posterior walls of the tympanic cavity there is a canal of the facial nerve. Due to the close anatomical proximity between this canal and the tympanic cavity facial nerve may be involved in the inflammatory process developing in the middle ear, and during operations on the middle ear there is a risk of injury to the facial nerve.
A chain is placed in the tympanic cavity auditory ossicles(Fig. 4), consisting of malleus, incus And stirrups. The hammer has a head, a handle and two processes (short and long).
The anvil consists of a body, short and long processes. The stirrup consists of two arches, a head and a foot plate. The handle of the hammer is rotated into the fibrous layer of the tympanic membrane, and the lower end of the handle forms a protrusion in the center of the tympanic membrane - the navel, and short shoot forms a protrusion in the anterior-superior part. These protrusions determine the characteristic appearance, which has an eardrum upon examination. The head of the malleus articulates with the body of the incus, and with its long process it articulates with the head of the stapes. The footplate of the stapes, as has been said, enters the oval window, which connects the middle ear with the inner ear. A certain tension of the eardrum and the chain of auditory ossicles is provided by two muscles - the tensor tympanic membrane and the stapedius. The first of them is attached to the handle of the malleus, and the second to the head of the stirrup.
Auditory, or Eustakhieva, the tube is a canal 3.5 cm long (in adults) connecting the tympanic cavity to the nasopharynx. The tympanic orifice of the Eustachian tube is located in the anterior wall of the tympanic cavity, and the nasopharyngeal orifice is located in the lateral wall of the nasopharynx. The part of the Eustachian tube that is adjacent to the tympanic cavity is bone, and the part facing the nasopharynx has cartilaginous walls. The entire Eustachian tube is lined with ciliated epithelium: the movement of its hairs is directed towards the nasopharynx. The walls of the cartilaginous part of the Eustachian tube, usually in contact with each other, diverge at the moment of swallowing (due to the contraction of the pharyngeal muscles), allowing air from the nasopharynx into the tympanic cavity. In young children, the Eustachian tube is shorter and its lumen is wider than in older children and adults.
Mastoid is a bone formation similar in shape to the nipple, which is where its name comes from. This is a process of the temporal bone located behind the auricle. In the thickness of the mastoid process there are cells that communicate with each other through narrow slits. The shape, size and number of these cells are very variable, but one of them, the largest, bears the name caves(antrum), always present. The cave communicates with the tympanic cavity through an opening in the rear wall of the latter. The cave is separated from the cranial cavity by a bone plate, sometimes very thin. The cells of the mastoid process sometimes reach the large venous sinus of the brain (transverse sinus) and are also separated from it only by a thin layer of bone.
In children under about two years of age, the mastoid process is not yet developed and looks like a bony tubercle. However, the cave already exists in a newborn child.
All cavities of the middle ear (tympanic cavity, Eustachian tube and mastoid cells) are filled with air, and their walls are lined with the thinnest mucous membrane, which is a continuation of the mucous membrane of the nasopharynx. The exchange of air in the middle ear occurs through the Eustachian tube: during swallowing movements, air from the nasopharynx enters the Eustachian tube, and from there into the tympanic cavity and partly into the cells of the mastoid process.
There is nothing surprising in the fact that humans are considered to have the most perfect sensory organ hearing aid. It contains the highest concentration nerve cells(over 30,000 sensors).
Human hearing aid
The structure of this apparatus is very complex. People understand the mechanism by which sounds are perceived, but scientists do not yet fully understand the sensation of hearing, the essence of signal transformation.
The structure of the ear consists of the following main parts:
- external;
- average;
- internal.
Each of the above areas is responsible for performing a specific job. The outer part is considered a receiver, which perceives sounds from the external environment, the middle part is an amplifier, and the inner part is a transmitter.
Structure of the human ear
The main components of this part:
- ear canal;
- auricle.
The auricle consists of cartilage (it is characterized by elasticity and elasticity). It is covered on top skin. At the bottom there is a lobe. This area has no cartilage. It includes adipose tissue, skin. The auricle is considered a rather sensitive organ.
Anatomy
The smaller elements of the auricle are:
- curl;
- tragus;
- antihelix;
- helix legs;
- antitragus.
Kosha is a specific covering lining the ear canal. It contains glands that are considered vital. They secrete a secret that protects against many agents (mechanical, thermal, infectious).
The end of the passage is represented by a kind of dead end. This specific barrier (tympanic membrane) is necessary to separate the outer and middle ear. It begins to vibrate when sound waves hit it. After the sound wave hits the wall, the signal is transmitted further, towards the middle part of the ear.
Blood flows to this area through two branches of arteries. The outflow of blood is carried out through the veins (v. auricularis posterior, v. retromandibularis). localized in front, behind the auricle. They also carry out the removal of lymph.
The photo shows the structure of the outer ear
Functions
Let's indicate significant functions, which are attached to the outer part of the ear. She is capable of:
- receive sounds;
- transmit sounds to the middle part of the ear;
- direct the sound wave to the inside of the ear.
Possible pathologies, diseases, injuries
Let us note the most common diseases:
Average
The middle ear plays a huge role in signal amplification. Strengthening is possible thanks to the auditory ossicles.
Structure
Let us indicate the main components of the middle ear:
- tympanic cavity;
- auditory (Eustachian) tube.
The first component (the eardrum) contains a chain inside, which includes small bones. The smallest bones play an important role in transmitting sound vibrations. Eardrum consists of 6 walls. Its cavity contains 3 auditory ossicles:
- hammer. This bone has a rounded head. This is how it is connected to the handle;
- anvil. It includes a body, processes (2 pieces) of different lengths. Its connection with the stirrup is made through a slight oval thickening, which is located at the end of the long process;
- stirrup. Its structure includes a small head bearing the articular surface, an anvil, and legs (2 pcs.).
The arteries go to the tympanic cavity from a. carotis externa, being its branches. Lymphatic vessels directed to the nodes located on the side wall of the pharynx, as well as to those nodes that are localized behind the concha.
Structure of the middle ear
Functions
Bones from the chain are needed for:
- Carrying out sound.
- Transmission of vibrations.
The muscles located in the middle ear area specialize in performing various functions:
- protective. Muscle fibers protect the inner ear from sound irritations;
- tonic. Muscle fibers are necessary to maintain the chain of auditory ossicles and the tone of the eardrum;
- accommodative The sound-conducting apparatus adapts to sounds endowed with different characteristics (strength, height).
Pathologies and diseases, injuries
Among the popular diseases of the middle ear we note:
- (perforative, non-perforative,);
- catarrh of the middle ear.
Acute inflammation can occur with injuries:
- otitis, mastoiditis;
- otitis, mastoiditis;
- , mastoiditis, manifested by wounds of the temporal bone.
It can be complicated or uncomplicated. Among the specific inflammations we indicate:
- syphilis;
- tuberculosis;
- exotic diseases.
Anatomy of the outer, middle, inner ear in our video:
Let us point out the significant importance of the vestibular analyzer. It is necessary to regulate the position of the body in space, as well as to regulate our movements.
Anatomy
The periphery of the vestibular analyzer is considered a part of the inner ear. In its composition we highlight:
- semicircular canals (these parts are located in 3 planes);
- statocyst organs (they are represented by sacs: oval, round).
The planes are called: horizontal, frontal, sagittal. The two sacs represent the vestibule. The round pouch is located near the curl. The oval sac is located closer to the semicircular canals.
Functions
Initially, the analyzer is excited. Then, thanks to the vestibulo-spinal nerve connections, somatic reactions occur. Such reactions are needed to redistribute muscle tone and maintain body balance in space.
The connection between the vestibular nuclei and the cerebellum determines mobile reactions, as well as all reactions to coordinate movements that appear when performing sports and labor exercises. To maintain balance, vision and muscle-articular innervation are very important.
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