The middle ear cavity fills. Functional anatomy of the outer, middle and inner ear. How is sound perception

The human hearing system is a complex system that has three main elements: external, middle and internal. It is the middle ear that plays the main function and thanks to it, a person can hear sounds. All diseases that occur in it pose a direct threat to human life and health.

The middle ear is located deep in the temporal bone. It consists of several organs, each of which is represented in the form of a system:

The tympanic cavity. It is located in it, thanks to which a person can hear music, voices and other sounds.
Auditory tube. A stream of air passes through it, which causes the eardrums to vibrate.
Mastoid. Separates the posterior cranial fossa and antrum.

The middle ear consists of several cavities, in the center of which is the tympanic. In appearance it resembles a tambourine or a prism. It is separated from the skull by a wall.The cavity contains the auditory ossicles, which perform the function of transmitting sound vibrations. Allocate stirrup, incus and malleus. The mechanism of their interaction resembles a system of levers.

One of the important elements of the middle ear is also the auditory tube, which connects the tympanic cavity with the external environment.

In newborns, it is much shorter and wider, which is very dangerous. Against the background of this feature, babies are most susceptible to the development of diseases of the middle ear.

The mastoid process is located behind the temporal bone. Inside it there are cavities that are interconnected by narrow slits. This increases the acoustic properties by several times.

Muscles are also located in the middle ear. Their main task is to strain the tympanic membrane and stirrup. They also help keep the bones in weight and regulate them. Thanks to them, a person can hear loud and quiet sounds.The middle ear plays an important role not only in transmission, but also in amplification of the signal. In his absence, a person would not have the ability to hear.

Classification of diseases

There are many different conditions that affect the middle ear. In medicine, it is customary to divide them into three broad categories:

Congenital. They are associated with the physiological and anatomical structure. Often they are hereditary, but may be the result of fetal developmental disorders. This type includes hearing loss, microtia.
Traumatic. The cause of development is injuries as a result of an accident, traffic accident, blows to the temple area, work injury. A rupture of the tympanic membrane can be observed after the strongest sharp noise, when the muscles did not have time to respond correctly. Injuries are often the cause of improper ear cleaning.
Infectious. They are accompanied by an inflammatory process. Viruses, bacteria, fungi become the cause of its development. It penetrates from the side of the external auditory canal, as well as along with the blood.

Each disease is dangerous to the life and health of the patient. This is because the middle ear is located in close proximity to the brain. This can cause inflammation of the membranes and cause the development of serious violations of its work.

Depending on the nature of the course of the disease, there are:

Sharp. Symptoms are growing rapidly, always pronounced. Lack of therapy at this stage leads to the transformation of the disease into a chronic form, which is difficult to treat.
Chronic. They are characterized by the presence of alternating periods of remission and exacerbation. They have the ability to pass for a long time without symptoms.

Only the attending physician can correctly diagnose the type and nature of the course of middle ear disease based on the results of the diagnosis.

Major diseases and their symptoms

Ear diseases are one of the most unpleasant pathologies, regardless of the reasons for their occurrence. They pose a threat to the patient's health and, if not treated promptly, cause not only hearing loss.

Often, inflammatory diseases are diagnosed, the causes of which are bacteria, infections:

... The symptoms are always pronounced. Patients complain of painful sensations of a shooting character, a decrease in the quality of hearing and the presence of purulent discharge from the ear canal. In the absence of therapy, the disease goes into a chronic stage, which is difficult to cure.
Mesotympanitis. The cause is inflammation of the membrane of the tympanic membrane. The main signs are hearing loss and purulent discharge. Often confused with purulent otitis media.
Epitympanitis. It is characterized by ingrowth of tissues of the external auditory canal into the cavity of the tympanic membrane. The danger of pathology is that there is a risk of disruption of the bone structure. The main symptom is hearing loss.
Cicatricial otitis media. It occurs against the background of limiting the mobility of the auditory ossicles. As a result, dense connective tissue begins to form. Patients complain of hearing impairment.

Diseases of the middle ear, regardless of the cause of their occurrence, have one distinguishing feature. It is quite difficult to get to the focus of infection or inflammation, since it is located deep. The environmental conditions in the ear are favorable for the growth of bacteria, and they quickly attack healthy areas. Therefore, when the first symptoms occur, you should consult a doctor. It is strictly forbidden to use the folk method of treatment.

Treatment methods

In the case when an infection has become the cause of painful sensations and other unpleasant symptoms, therapy is required to destroy the pathogenic flora.

For this, antibiotics are prescribed in the form of tablets or ointments. Symptomatic therapy consists in prescribing:

Pain relievers. The drugs of the NSAID group are used. They not only relieve pain, but also eliminate inflammation. The most effective is "".
Antiviral. Helps reduce virus activity. Appointed "Arbidol", "Kagocel", "".
Anti-inflammatory. Contribute to the relief of the inflammatory process. The use of "Diclofenac" or "Ketoprofen" is shown.
Antihistamines. Necessary for the removal of intoxication, which develops against the background of the vital activity of pathogenic microorganisms. Relieve nausea. Eliminate weakness, apathy and headache will help "Suprastin", "Erius".

If there is an accumulation of purulent masses in the middle ear cavity, a procedure is prescribed to force it out. It is called paracentesis and is performed by incising the tympanic membrane. The patient's condition improves significantly after the purulent masses come out. After the procedure, the ear cavity is treated with an antiseptic solution.

More information about the structure and function of the ear can be found in the video:

Advanced Middle Ear Diseases Can Cause Hearing Loss

The middle ear is located in close proximity to the brain. The inflammatory process that develops in the cavities can spread to the meninges.

The consequences of untimely treatment or its absence are:

Sepsis.
Inflammation of the facial nerve.
A ruptured eardrum.
Complete or partial hearing loss.

Against the background of brain inflammation, a decrease in the quality of vision, mental activity and the ability to perceive information in various volumes may occur.

The middle ear is a complex mechanism made up of many elements. EIts function is to convert air currents into sound. It is thanks to him that a person is able to hear sharp, strong, quiet dull and sonorous sounds. A minor disturbance in the operation of the mechanism affects the quality of hearing. It can be completely or partially lost. In certain cases, it cannot be restored.

There are many diseases that affect the ear. Infections, viruses become the cause. Pain can also occur against the background of an injury. When symptoms appear, you should consult a specialist to determine the exact cause of the unpleasant symptoms. Self-medication and lack of therapy in this case can lead to sad consequences.

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

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

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

Anatomical structure of the organ of hearing

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

Interesting. When a person needs to hear something, he "exposes" the right ear closer, and for good reason. Scientists have shown that the hearing acuity of the right ear is slightly higher than that of the left.

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

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

Middle ear structure

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

The tympanic cavity.
The system of the cavities of the mastoid process.

Detailed anatomical structure of the middle section of the hearing organ

Tympanic cavity- an important element of this department. It contains the auditory ossicles: malleus, incus, stapes. Their names come from the peculiarity of their structure and functioning. The system of mutual work of these bones is similar to the mechanism of levers.

All 3 ossicles are connected to each other. The tiny handle of the hammer is centered in the tympanic membrane and the head is connected to the incus. She, in turn, connects with the stirrup. The latter is connected to the inner ear through the oval window.

Reference. Such a device of bones determines not only the transmission, but also the amplification of sound. It amplifies approximately 60-70 times.

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

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

The location of the mastoid airway system

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

The anatomy of this section provides for the presence of muscle fibers. In this situation, there are only two of them - the stapes muscle and the muscle that strains the eardrum. They are responsible for the function of maintaining and regulating the auditory ossicles.

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

Where is the middle ear

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

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

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

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

What is the middle ear cavity filled with?

The Eustachian tube evens out the pressure in the middle ear, otherwise we would constantly feel congestion in our ears

Most interested people ask the question: "What is the cavity of the middle ear of a person filled with?" It would seem a very simple question, the answer to which comes by itself, if only to think logically.

But no, for some reason this issue generates a lot of controversy on the forums. This is because some people argue hotly, believing that the middle ear is filled with some kind of liquid. We will not even give the names here, because there are a huge number of options. And all are unfaithful!

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

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

If there was no such device and air communication, then we would constantly feel a feeling of stuffiness in our ears.

Middle ear functions

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

The main function of the middle ear is sound conduction.

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

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

Important. However, such protection is powerless in the presence of sudden deafening sounds. For example, an explosion can damage an acoustic device because the muscle contractions in the middle ear are slightly late. It takes about 10 ms for them to react.

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

Dust and moisture.
Mechanical stress.
The penetration of pathogens.
Jumps in atmospheric pressure indicators.

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

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

The human ear has a very complex anatomical design, which allows you to capture sound waves, determine the direction of the sound source and correctly identify it. It consists of three main sections: the outer, middle and inner ear. Each of which has strictly defined functions and special structure. The human middle ear primarily converts sound waves into nerve impulses. This is its main, but not the only function.

General structure and principle of operation

The middle ear begins just behind the eardrum, which is located at the end of the ear canal and separates it from the outer ear. There are three main elements in the middle ear:

tympanic cavity;
mastoid processes;
auditory tube.

The eardrum is a small piece of thin connective tissue that is directly involved in the transformation of sound waves captured by the outer ear.

The tympanic cavity of the middle ear is located in the notch of the temporal bone. Inside it, in the immediate vicinity, are the three smallest bones of the human skeleton: the hammer, the stirrup and the incus. Acoustic waves cause the eardrum to vibrate, and these vibrations are transmitted to the bones. And the stapes through the oval window sends a signal to the liquid that fills the inner ear - perilymph.

Interestingly, the design of the ossicles allows not only transmitting, but also significantly amplifying sound. The surface of the stapes is an order of magnitude smaller than the area of the eardrum, which means that it hits the oval window much harder, giving a person the opportunity to hear even very quiet sounds.

Protective functions of the middle ear

The function of the middle ear is not limited to sound conduction. It is also a reliable protective barrier that protects the delicate inner ear from:

ingress of moisture, particles of dust and dirt;
penetration and reproduction of pathogenic microorganisms;
too intense exposure to a sound wave;
sudden changes in atmospheric pressure;
mechanical stress.

The middle ear cavity is filled with air and is connected to the nasopharynx via the Eustachian tube. Under normal conditions, the air pressure is the same on both sides of the tympanic membrane. But if the atmospheric pressure changes sharply in either direction, then this stretches the eardrum and can lead to its rupture.

This phenomenon is called barotrauma. The same thing occurs when a sharp dive to great depths. To prevent barotrauma, diving should be done slowly. And when taking off or landing an airplane - open your mouth or make swallowing movements often.

The anatomy of the middle ear can partially compensate for loud sounds. It houses two very small muscles, one of which controls the tension of the tympanic membrane, and the other controls the amplitude of the stapes. The protective mechanism laid down by nature ensures a reflex contraction of these muscles when sounds are too loud. The movement of the stapes is limited and the ear's sensitivity is temporarily reduced. It takes about 10 ms to trigger it. Therefore, during explosions, shots and other impetuous sounds, it does not have time to compensate for the noise.

Diseases of the middle ear

The structure of the middle ear is such that in case of its diseases, the normal conduction of sound suffers first of all and the threshold of auditory sensitivity is sharply reduced. The causes of inner ear disease are most often trauma, hypothermia, or exposure to pathogenic microorganisms.

Moreover, viruses and bacteria can enter the ear not only through the external auditory canal, but also from the mouth or nose through the Eustachian tube. That is why ARVI, flu, rubella, tonsillitis are often complicated by otitis media.

Among the most common diseases of the middle ear, doctors note:

acute and chronic otitis media;
barotrauma;
mechanical injury;
congenital pathologies;
hearing loss of 1-4 degrees.

Purulent otitis media is especially dangerous, which in the absence of proper treatment can lead to inflammation of the meninges (meningitis) and even general blood poisoning (sepsis). Pus collects behind the eardrum and presses on it, causing severe pain. Sometimes it is partially perforated, and in some cases, it is completely ruptured, which can lead to partial or complete hearing loss.

Unfortunately, the structure of the middle ear is such that diseases appear already at the stage when the inflammatory process has developed. The main symptoms of the disease of this organ are: a sharp shooting pain, an increase in body temperature, often reddening of the tragus, headache, periodic dizziness.

With otitis media, pus or a yellowish exudate with an unpleasant odor may be discharged from the ear. If these symptoms appear, you should immediately consult a doctor. Delay and improper treatment can lead to very serious consequences.

The ear has 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 formation of the speech function, and consequently, the mental activity of a person. Distinguish between the outer, middle, inner ear.

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 ear provide sound transmission, while the inner ear contains receptors for both auditory and vestibular analyzers.

Outer ear. The auricle is a curved plate of elastic cartilage, covered on both sides by the 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 as macro- and microotia, aplasia, protrusion, etc. are known. Disfigurement of the auricle is possible with perichondritis (trauma, frostbite, etc.). Its lower part - the lobe - is devoid of a cartilaginous basis and contains fatty tissue. In the auricle, a helix, an anthelix, a tragus, an antitragus are distinguished. The curl 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).

Topographic and anatomical relationships of parts of the ear canal are of clinical importance. Front wall - borders on the joint capsule of the lower jaw (it is important for otitis externa and injuries). From below - the parotid gland is adjacent to the cartilaginous part. The anterior and lower walls are pierced with 2 to 4 vertical slits (santorinii slits), through which suppuration can pass from the parotid gland to the auditory meatus, as well as in the opposite direction. Back – bordered by the mastoid process. In the depths of this wall, the descending part of the facial nerve passes (radical surgery). Upper – bordered by the middle cranial fossa. Top-back – is the front wall of the antrum. Its omission indicates purulent inflammation of the cells of the mastoid process.

The external ear is supplied with blood from the external carotid artery system due to the superficial temporal (a. Temporalis superficialis), occipital (a. Occipitalis), posterior ear and deep ear arteries (a. Auricularis posterior et profunda). Venous outflow is carried out in the superficial temporal (v. Temporalis superficialis), external jugular (v. Jugularis ext.) And jaw (v. Maxillaris) veins. Lymph is diverted 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 ear nerve from the superior cervical plexus. Due to the vagal reflex with sulfur congestion, foreign bodies, cardialgic phenomena, cough are possible.

The boundary between the outer and middle ear is the eardrum. The diameter of the tympanic membrane (Fig. 1) is approximately 9 mm, the thickness is 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. The b / p consists of three layers:

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

internal - the 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, therefore the eardrum is not elastic and can rupture with sudden pressure fluctuations or very strong sounds. Usually, after such injuries, a scar is subsequently formed due to the regeneration of the skin and mucous membrane, the fibrous layer does not regenerate.

In the b / p, two parts are distinguished: stretched (pars tensa) and non-stretched (pars flaccida). The stretched 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 temporal bone scales; this part does not have a fibrous layer.

When otoscopic examination, the color is non-pearl or pearl gray with a low sheen. For the convenience of clinical otoscopy, the b / p is mentally divided into four segments (anteroposterior, antero-inferior, posterior superior, posterior inferior) in two lines: one is a continuation of the hammer handle to the lower edge of the b / p, and the second passes perpendicular to the first through the umbilicus b / p.

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

External (webbed) the wall of the tympanic cavity is formed over a greater extent by the inner surface of the b / p, and above it - by the upper wall of the bony part of the ear canal.

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

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

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

Anterior (sleepy) the wall in the upper half is occupied by the tympanic opening of the auditory tube. Its lower part is bordered by the canal of the internal carotid artery. Above the auditory tube is the semicanal of the muscle that strains the tympanic membrane (m. Tensoris tympani). The bone plate separating the internal carotid artery from the mucous membrane of the tympanic cavity is pierced by thin tubules and often has dehiscence.

Back (mastoid) the wall is bordered by the mastoid process. The entrance to the cave opens in the upper part of its back wall. In the depths of the posterior wall, the canal of the facial nerve passes, from this wall the stapes muscle begins.

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

The ear ossicles are located in the tympanic cavity, which are involved in sound conduction. The auditory ossicles - malleus, incus, stirrups - are a closely connected chain that is located between the eardrum 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 spliced with the b / p, the short process protrudes outwardly the upper section of the b / p, and the head articulates with the body of the incus.

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

Stirrup - it distinguishes head, front and back legs, interconnected by a plate (base). The base covers the window of the vestibule and is reinforced with the window using a ring-shaped ligament, making the stirrup movable. And this ensures a constant transmission of sound waves into the inner ear fluid.

Muscles of the middle ear. Muscle straining b / p (m. Tensor tympani), is innervated by the 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 bony canals, only their tendons pass into the tympanic cavity. They are antagonists, contracting 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 pharyngeal-tympanic tube connects the tympanic cavity with the nasopharynx. The auditory tube consists of the bony and membranous-cartilaginous sections, opening into the tympanic cavity and the 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 the fossa, bounded above and behind by the protrusion of the tubal cartilage, behind which there is a depression - the Rosenmüller fossa. The mucous membrane of the tube is covered with multinucleated ciliated epithelium (the movement of cilia is directed from the tympanic cavity to the nasopharynx).

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

The blood supply to the middle ear is carried out by the 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 retropharyngeal lymph nodes and deep nodes. The innervation of the middle ear comes from the glossopharyngeal, facial and trigeminal nerves.

Due to topographic and anatomical proximity facial nerve to the formations of the temporal bone, we will trace its course. 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 stony part of the temporal bone, near the labyrinth, its stony ganglion is located. In this zone, a large petrosal nerve branches off from the trunk of the facial nerve, containing parasympathetic fibers for the lacrimal gland. Further, the main trunk of the facial nerve passes through the thickness of the bone and reaches the medial wall of the tympanic cavity, where it turns posteriorly (first knee) at a right angle. The bony (fallopian) canal of the nerve (canalis facialis) is located above the window of the vestibule, where the nerve trunk can be damaged during surgery. At the level of the entrance to the cave, the nerve in its bony canal is directed steeply downward (second knee) and exits the temporal bone through the styloid opening (foramen stylomastoideum), disintegrating in a fan-like fashion into separate branches, the so-called pes anserinus, which innervate the facial muscles. At the level of the second knee, the stapedius departs from the facial nerve, and caudally, almost at the exit of the main trunk from the styloid opening, the tympanic string. The latter passes in a separate tubule, enters the tympanic cavity, heading anteriorly between the long leg of the incus and the handle of the malleus, and leaves the tympanic cavity through the stony-tympanic (glazer) fissure (fissura petrotympanical).

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

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

Bone semicircular canals are located in the posterior lower part of the bone labyrinth in three mutually perpendicular planes. There are lateral, anterior and posterior semicircular canals. These are arcuate curved tubes in each of which two ends or bony legs are distinguished: expanded or ampullar and unexpanded or simple. Simple bony legs of the anterior and posterior semicircular canals are connected to form a common bony leg. The canals are also filled with perilymph.

The bony cochlea begins in the antero-inferior part of the vestibule with a canal, which bends spirally and forms 2.5 curls, as a result of which it is called the cochlear spiral canal. Distinguish between the base and the top of the snail. The spiral canal winds around the cone-shaped bone rod and blindly ends at the apex of the pyramid. The bone plate does not reach the opposite outer wall of the bone 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 is the staircase of the vestibule and the lower one is the tympanic staircase. Both ladders contain a perilymph and communicate with each other through a hole at the apex of the cochlea (helicotrema). The staircase of the vestibule is bordered by the window of the vestibule, closed by the base of the stirrup, the tympanic staircase - with 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 pia maze.

The membranous labyrinth is suspended in the perilymph, filling the bony labyrinth. In the membranous labyrinth, two devices 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 spiral-wound canal - the cochlear duct, which, like the cochlea, makes 2½ turns. In cross section, the membranous cochlea has a triangular shape. It is located on the top floor of the bony cochlea. The wall of the membranous cochlea, bordering on the tympanic ladder, is a continuation of the spiral bone plate - the tympanic wall of the cochlear duct. The wall of the cochlear duct, bordering the staircase of the vestibule - the vestibule plate of the cochlear duct, also departs from the free edge of the bone plate at an angle of 45º. The outer wall of the cochlear duct is a part of the outer bony wall of the cochlear canal. A vascular strip is located on the spiral ligament adjacent to this wall. The tympanic wall of the cochlear duct consists of radial fibers arranged in the form of strings. Their number reaches 15,000 - 25,000, their length at the base of the snail is 80 microns, at the top - 500 microns.

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

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 the tunnels to the spiral node at the base of the spiral bone plate. In total, there are up to 30,000 ganglion cells. The axons of these ganglion cells connect in the ear canal to form the cochlear nerve. Above the spiral organ is the integumentary membrane, which begins near the point of origin of the vestibule wall of the cochlear duct and covers the entire spiral organ in the form of a canopy. The stereocilia of hair cells penetrate into 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 face of the pyramid, and ends at the bottom of the internal auditory canal. It contains the perdoor-cochlear nerve (VIII), consisting of the superior vestibular root and the inferior cochlear. Above it is the facial nerve and next to it the intermediate nerve.

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

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

Auditory bones. They represent a stirrup, malleus and anvil. It is these details that help to transmit sounds, and distinguish them in strength and height. The features of the ossicles help protect the hearing aid from harsh and loud sounds.
Auditory tube. This is the passage that connects the nasopharynx with the tympanic cavity. Its mouth is closed when a person swallows or sucks something. Newborn babies have a wider and shorter auditory tube for some time than in adults.
The tympanic cavity. It is this part of the middle ear that contains the ossicles described above. The location of the tympanic cavity is the area between the outer ear and the temporal bone.
Mastoid. This is the convex part of the temporal bone. It contains cavities that are filled with air and communicate with each other through narrow holes.

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

round window;
oval window in the ear.

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

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

Middle ear functions

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

maintaining the efficiency of the tympanic membrane;
transmission of sound vibrations;
protecting the inner ear from harsh and too loud sounds;
ensuring the receptivity of sounds of different strength, height and volume.

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

Diseases of the middle ear

Experts call the following signs and conditions of a person the main symptoms of problems in the middle ear area:

ear pain of varying intensity (mostly very severe);
feeling of congestion;
decreased or complete hearing loss;
discharge of fluid or pus from the ear canal;
increased body temperature;
decreased appetite and poor sleep;
discoloration of the eardrum more red.

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

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

Important! Often, problems with the middle ear can arise against the background of various infectious diseases, for example, tonsillitis, sinusitis, rhinitis, laryngitis, flu. Improper ear and nose care, injuries, water entering the ear canal, hypothermia and drafts are also common causes.

Prevention of middle ear diseases

Wear a hat in winter

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

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

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

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