The structure of the middle ear and diseases affecting the organ. What is the purpose of the auditory tube and methods for its diagnosis

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 subjected to inflammatory diseases. It is located behind the eardrum, not reaching the 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 bone ear 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 that is covered bottom surface stirrups. 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. Middle is the largest part, the space between the top and lower limit. 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 articular cartilage, serves to articulate the anvil and 2 legs - one straight, and the second 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 minor sound waves allow you 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. On the 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 bone structure. And the part adjacent to the nasopharynx has cartilaginous walls. In the normal state, 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 by an 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 blood pressure may change and the heartbeat may accelerate.
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 thanks to it it is observed 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 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 of the auditory organ. But it is very sensitive, so it should be protected from negative impacts . Otherwise there may appear various diseases leading to hearing impairment.

The Eustachian tube is a small canal that connects the ear to the nose. The patency of the Eustachian tube can be impaired due to colds and allergies. Serious cases require observation by an otolaryngologist. WITH mild cases can be managed at home with home remedies, over-the-counter medications, and prescription solutions.

Steps

Treating ear plugs at home

Symptoms Colds, allergies, infections and swelling lead to disruption of the passage of air through eustachian tube. Due to changes in pressure, fluid accumulates in the inner ear, causing following symptoms:

Movements of the lower jaw. This is very simple technique called the Edmonds maneuver. Push your lower jaw forward and move it from side to side. If the ear is not severely blocked, this method will effectively restore normal air flow.

Use the Valsalva technique. This method forces air flow through the blocked passage, so it must be done carefully. A strong flow of air when exhaling can cause rapid change blood pressure and heart rate.

Try Toynbee's method. Like the Valsalva technique, the Toynbee technique is designed to relieve ear congestion. But instead of changing air pressure when breathing, Toynbee's method uses changing air pressure when swallowing. To perform the Toynbee method, do the following:

pinch your nostrils;
take a sip of water;
swallow;
Repeat the process until you feel the ear congestion go away.

Blow up the balloons with your nose. It sounds ridiculous, but this method effectively equalizes the pressure in the ears. Unfortunately, a special device for this technique (Otovent) is not sold in Russia, but you can order it online or make it yourself. It is a ball with an attachment for the nostril. You may already have attachments for a nasal aspirator at home - in this case, making such a device yourself will not be difficult.

Swallow with your nose pinched. This is the Lowry method. Before simply swallowing, you need to increase the pressure, as if straining. When you hold your breath and strain, you will feel the air trying to escape through all the passages. This can be difficult for some people to swallow. Be patient and you will feel a click in your ears.

Apply a heating pad or warm towel to your ear. This will relieve pain and may relieve ear congestion. The heat from the compress can relieve swelling and increase the patency of the Eustachian tube. If you are using a heating pad, place a cloth between your skin and the heating pad to avoid getting burned.

Use vasoconstrictors for the nose. Ear drops will not help with congestion in the ears because the connection between the ear and nose is located in a place inaccessible to the drops. Therefore, in such cases they use vasoconstrictor sprays for the nose. Place the spray dispenser in one nostril almost perpendicular to your face. Inhale forcefully after spraying - this must be done so strongly that the liquid gets into the back throat, but not enough to swallow it or put it in your mouth.
- Try any of the above methods after using the drops - they may be more effective after using the spray.
Accept antihistamine if congestion is associated with allergies. Although antihistamines are not intended to treat ear congestion, they may be effective in relieving allergic swelling. Consult with an allergist to prescribe the most effective drug.
- Please note that antihistamines are not recommended for people with ear problems.
Medical solution to the problem
1. Therapeutic nasal sprays. Regular over-the-counter medications can be used, however the greatest effect have prescription vasoconstrictors. If you suffer from allergies, ask your doctor to prescribe steroid and/or antihistamine nasal sprays.
  
  Take antibiotics for an ear infection. Often, a blocked eustachian tube is not harmful to health and does not last long, but it can sometimes lead to an ear infection. If the blockage does not go away for a long time, contact your otolaryngologist to prescribe treatment. The doctor will prescribe antibiotics for temperatures over 39°C for more than two days.
  - Take your medications as directed. Drink it full course antibiotics, even if you feel better.
2. Discuss the possibility of a myringotomy with your doctor. In severe cases, your doctor may recommend surgical solution Problems. There are two surgeries, and myringotomy is the quickest option. During this operation, the surgeon makes a thin incision in the eardrum and removes excess liquid from the middle ear. It may seem counterintuitive, but it is necessary for the incision to heal. slowly. If the incision is left open for a long enough period of time, the swelling of the eustachian tube may subside. If the ear heals quickly (in less than 3 days), fluid will again accumulate in the middle ear and symptoms will return.
3. Consider other pressure equalization methods. Another surgical method getting rid of congestion in the ear is used for advanced processes. Just as with a myringotomy, the doctor makes an incision in the eardrum and suctions out the fluid that has accumulated in the middle ear. A small tube is inserted into the incision to assess the condition of the middle ear during the healing period. The tube is removed on its own after 6–12 months. This method is used in patients with chronic diseases of the Eustachian tube.
  - Be sure to protect your ears from water if you have tubes in your eardrums. Use earplugs or cotton balls when swimming and showering.
  - If water gets through the tube into the middle ear, it can cause inflammation.
4. Treat the cause. A blocked eustachian tube usually indicates another medical condition, accompanied by mucus discharge and swelling. The most common illnesses include colds, flu, sinus infections and allergies. Do not start these diseases to prevent ear inflammation. Treat colds and flu at the first symptoms, and consult your doctor for allergies and sinus infections.
  - If you know you have fluid in your ears, do not use ear removers. earwax. They can cause infection because they are liquid and not wax.
  - If you have ear pain, do not lie horizontally.
  - Don't drink cold water, but some warm drink, for example, tea.
  - Try dissolving a few in your mouth chewable tablets papaya. Papayotine, the main ingredient in unripe papaya, is an excellent mucus dissolver.
  - You can also try fenugreek.
  - Place an extra pillow under your head to help drain fluid from your nose while you sleep.
  - For pain caused by blocked ears, ask your doctor to prescribe pain-relieving drops. To relieve pain, you can also try over-the-counter medications such as ibuprofen, paracetamol, or naproxen.
  - Wear a hat that covers your ears to keep your head cool.

Tests

892-01. The auditory tube of the middle ear provides
A) equalization of pressure on opposite sides of the eardrum
B) protection against microorganisms entering the middle ear cavity
B) transmission of sound vibrations from the eardrum to the auditory ossicles of the middle ear
D) fluid vibrations in the cochlea of the inner ear

Answer

892-02. The human inner ear is located in a bone cavity
A) parietal
B) temporal
B) occipital
D) frontal

Answer

892-03. The figure shows a diagram of the hearing organ. What letter on it indicates the cavity in which the auditory ossicles are located?

Answer

892-04. Determine the name of the ear structure from its description: “A spiral bone canal, coiled like a shell into 2.5 turns, into which a membranous labyrinth is inserted.”
A) vestibular apparatus
B) middle ear with a system of auditory ossicles
B) auricle
D) snail

Answer

892-05. Sound energy in nerve impulses transform
A) eardrum
B) external auditory canal
B) auditory ossicles
D) hair cells of the cochlea

Answer

892-06. When loud sound balancing the pressure on eardrum from the side of the middle ear cavity it is provided by the nasopharynx and
A) the auditory ossicular system
B) auditory tube
B) vestibular apparatus
D) snail

Answer

892-07. Receptors that perceive sound signals, are situated in
A) eardrum
B) cerebral cortex
B) snail
D) external auditory canal

Answer

892-08. Which sensory system is the organ depicted part of?

A) sense of smell
B) touch
B) hearing
D) taste

Answer

892-09. The auditory tube connects
A) nasopharynx with middle ear cavity
B) outer ear with middle ear
B) middle ear with inner
D) hammer and anvil

US President Donald Trump, during a working trip to Nevada, where the famous American nuclear test site has been located since 1950, confirmed Washington's intention to withdraw from the Intermediate-Range Nuclear Forces Treaty (INF), as previously reported by the New York Times. This cornerstone agreement in the field of nuclear safety was signed in December 1987 in Washington by the presidents of the USSR and the USA, Mikhail Gorbachev and Ronald Reagan. For the first time in history, the treaty contributed to the elimination of an entire class of heavy weapons - the destruction of American and Soviet ground-launched ballistic and cruise missiles with a flight range of 500 to 5,500 kilometers.

By 1991, almost 2,700 short- and medium-range missiles had been destroyed. The agreement prevents the United States and Russia from possessing, producing or testing ground-launched cruise missiles with a certain range.

However, Trump left himself “room for maneuver”, stipulating that the United States could remain in the Treaty if Russia and China sit down at the negotiating table with Washington and are ready to conclude a new agreement with the Americans. Otherwise, the United States reserves the right to begin developing new types of weapons.

Sources in the American administration in an interview with the New York Times admitted that, according to Trump, the INF Treaty is keeping America from creating a new type of weapon to counter the growing arsenal of Chinese intermediate-range missiles. The head of the White House was literally angry when he found out that Beijing is not obliged to comply with the provisions of the treaty, since it is not a signatory. The PRC, like some other countries, does have missiles prohibited by the agreement. And, according to Americans, they can account for up to 95 percent of China’s missile potential.

However, in Nevada, Trump unexpectedly “switched the arrows from China to Russia,” declaring in a sharp and ultimatum manner that the reason for Washington’s withdrawal from this agreement was Moscow’s position. According to the head of the White House, Russia has allegedly violated this agreement for decades and “abused it.” As usual, Trump did not provide any arguments or facts to support his emotional and harsh statement. And, as Russian experts and diplomats noted, he used rumors and his much-disliked fake news, this time from the “missile sphere,” to blackmail Russia.

The US withdrawal from the INF Treaty could have irreparable consequences for global security

Another loud and pathetic statement by the current owner of the White House is intended to promote his concept of “America First.” It logically fits into the president’s policy of withdrawing from basic legal international agreements and breaking off relations with various world organizations. Trump, having barely settled in at 1600 Pennsylvania Avenue, managed to withdraw from the Paris climate agreement, break with the nuclear deal with Iran, and also indicate the lack of interest of the current US administration in a number of international associations. The latest in this series of “partings” was the decision to terminate membership in the Universal Postal Union.

It is no coincidence that the very tone and ultimatum of the statement from the head of the White House provoked a harsh reaction in Moscow. Deputy Foreign Minister of the Russian Federation Sergei Ryabkov said that Russia condemns the US attempts to resort to blackmail in the matter of the INF Treaty. According to Ryabkov, Russia strictly complies with the provisions of the agreement and has been pointing out violations of this agreement by Washington for many years. As Konstantin Kosachev, Chairman of the Federation Council Committee on International Affairs, emphasized in turn, withdrawal from the agreement will make it possible for the United States to deploy ground-based missiles with a range of up to 5.5 thousand kilometers in close proximity to Russian borders.

Trump's current decision could have irreparable consequences for global security. The last time the United States withdrew from a major arms treaty was in 2001. Then President George W. Bush ended US participation in the Anti-Ballistic Missile Treaty, which freed the Americans to deploy the so-called missile defense shield in Eastern Europe in close proximity to Russia's borders. The actions of the Bush administration caused a sharp reaction from Moscow.

Trump’s decision looks all the more strange against the backdrop of his relatively “peace-loving” statements made at a meeting with Russian President Vladimir Putin in Helsinki that “such a race gives rise to expensive nuclear weapons modernization programs in every state.” Trump called it "very, very bad policy" at the summit.

Meanwhile, as the Guardian reports, Donald Trump made the decision to withdraw from the INF Treaty under pressure from the famous hawk of American foreign policy, his national security adviser John Bolton. Alexandra Bell, a former senior official in the American administration, said that the head of the White House “does everything that Bolton whispers in his ear.” According to the publication, Bolton and Tim Morrison, the chief adviser on arms control at the National Security Council, are blocking any White House negotiations on extending the Strategic Arms Treaty (START-3), which expires in 2021. Moscow has repeatedly made it clear that it intends to extend this basic agreement in the field of ensuring international security. Otherwise, a new and more terrible nuclear arms race could be unleashed. Bolton previously called such treaties “unilateral disarmament,” promoting obsession that Washington signed them allegedly to the detriment of its own national security. Bolton, a longtime opponent of arms control, next week flies to Moscow and it is he who intends to notify Vladimir Putin about the Americans’ withdrawal from the INF Treaty. According to Sergei Ryabkov, during Bolton’s visit, the Russian side will demand clear explanations from him about further steps under the agreement. The leaders of the two countries themselves may meet in Paris on November 11 to celebrate the centenary of the end of the First World War.

Infographics "RG": Anton Perepletchikov / Leonid Kuleshov

Malcolm Chalmers, Deputy Director General of the British Royal Joint Services Institute:

This is the most serious nuclear arms control crisis since the 1980s. If the INF Treaty collapses and the New START Treaty, which expires in 2021, is not renewed, the world could be left without any restrictions on the nuclear arsenals of states possessing such weapons for the first time since 1972.

Day in history

“In these days of early December 1987, the capital of the United States at first glance looked as usual: in comparison with New York or Chicago, relatively unfussy, somewhat prim... But the ordinariness of the usual environment was only apparent. What was happening then in Washington, will certainly be included in the textbooks from which our children and grandchildren will learn, learning how humanity managed to take the first step from the centuries-long accumulation of ever new and more destructive mountains of weapons to the elimination of deadly arsenals,” with these words TV journalist Valentin Zorin began the story about Mikhail’s historic visit Gorbachev to America. His chronicle is shown in documentary film"December, 1987." On the evening of December 7, a plane with the Soviet Secretary General on board landed at the Andrews Air Force Base. The delegation from the USSR was met by Republican Secretary of State George Shultz. And the very next day, the main celebrations took place on the south lawn of the White House, filled with politicians and diplomats. In honor of the arrival of the Moscow guests, whom the crowd greeted with applause and shouts of approval, the guard of the “Old Guard Regiment” marched. Stars and stripes interspersed with Soviet standards. Ronald Reagan and the first lady came out to meet a car with red flags, in which Mikhail Gorbachev and his wife arrived. Accompanied by artillery salvoes, the American Marine Corps Band performed the anthem of the USSR and then the USA. The main result of the visit was the signing of the INF Treaty. In the afternoon, Washington time, Gorbachev and Reagan followed the red carpet to the East Room of the White House, where the texts of the treaty were waiting for them on the table. As the leader of the USSR said then, its signing gives the powers “a chance to take the road leading away from the impending catastrophe.” With smiles and again to applause, Mikhail Gorbachev and Ronald Reagan signed the document and also exchanged hands at the initiative of the Soviet leader.

Mikhail Gorbachev and Ronald Reagan sign the Intermediate-Range Nuclear Forces Treaty at the White House. December 8, 1987. Photo: Lizunov Yuri, Chumichev Alexander / TASS Photo Chronicle

It is known that the Intermediate-Range Nuclear Forces (INF) Treaty, which entered into force in 1988, prohibits the signatories from producing, testing and deploying ground-launched ballistic and cruise missiles with a maximum flight range of 500 to 5,500 kilometers.

According to Russian diplomats, representatives of the Ministry of Defense and experts, there are at least four points on which Russia has claims against the United States in terms of fulfilling the obligations of the agreement signed more than three decades ago.

The first point concerns American missile defense facilities in Poland and Romania, which, according to Pentagon plans, will be equipped with Mk 41 universal launchers. It is no secret that, if necessary, these launchers can easily be converted to launch BGM-109 Tomahawk cruise missiles with a range of from 1250 to 2500 kilometers. Experts say: in a few hours, part of the software in the Mk 41 control system can be replaced, and the complex will be ready to fire Tomahawks.

In addition, five years ago the United States began test launches from the ground of the AGM-158B aircraft cruise missile with a range of a thousand kilometers. And last December, Trump signed a defense bill, which, among other things, contains a $25 million program to develop a new cruise missile of this type.

There was information that such ammunition would make it possible to destroy important civilian and military targets within 12-15 minutes, while sea-based cruise missiles allowed by the treaty would fly to targets several times longer. Finally, do not forget about the long-range attack drones available to the US military. When the INF Treaty was signed in 1987, there were no drones in the armies of the two countries yet.

Therefore, formally they do not fall under the restrictive clause of the agreements. But in fact, attack drones are in many ways reminiscent of cruise missiles, and, unlike ammunition, they can be used repeatedly. For example, the same American MQ-1 Predator and the more modern MQ-9 Reaper are capable of flying 1100 and 1852 kilometers, respectively. Not just fly by, but strike with anti-tank guided missiles or adjustable aerial bombs. It turns out that the United States, with its attack drones, simply “bypassed” the INF Treaty.

In the US, many politicians criticized Trump's decision. Republican Senator Rand Paul opposed the White House's plans to withdraw from the INF Treaty. In his opinion, Trump adviser John Bolton should not be allowed within easy reach of a cannon shot. foreign policy USA.

"This destroys decades of bipartisan work on arms control since Ronald Reagan," Paul tweeted. "We shouldn't do this. We need to solve the treaty problem and move forward." As Democratic Senator Ed Markey recalled, the reason for concluding the INF Treaty was the understanding that “a nuclear war cannot be won and should never be started.” He called the White House's decision a "betrayal of NATO" because it frees Russia's hands.

“For the United States, such a goal is a disaster,” says Daryl Kimball, director of the American Arms Control Association. “This will open the door for Russia to expand its own arsenal.” Since the arrival of Donald Trump The White house The delegations of the two countries held only one meeting to discuss differences over the INF Treaty, and therefore, according to Kimball, “diplomatic options are by no means exhausted.” In his opinion, Washington's actions are an "epic mistake", "increase the risks for Europe", and "open the door to an arms race." Former US permanent representative to NATO Ivo Daalder recalled that the INF Treaty marked the end of the Cold War. “Withdrawing from the agreement now will in no way strengthen US security, and will also worsen relations with NATO,” Daalder believes. Leaving the agreement now is a mistake, commented an expert from the authoritative Brooking Institution and former ambassador USA in Ukraine Steven Pifer. - There are more smart ways solving the problem." He expressed hope that "sensible people in Washington, especially in the Pentagon," will be able to intervene in the decision-making process on the INF Treaty.

In turn, State Minister of the German Foreign Ministry Niels Annen called Trump's decision to withdraw from the INF Treaty "catastrophic." He wrote about this on his Twitter on October 21.

“Trump’s decision can be called catastrophic,” the Minister of State wrote, “but we will continue to work on disarmament.”

As Annen noted, Europe's task now is to prevent the potential of medium- and short-range missiles from being built up.

The opposition in Germany is also extremely disapproving of the American decision. Thus, an expert from the German opposition Left Party, Alexander Neu, said that withdrawal from the INF Treaty means that the likelihood of a nuclear war increases. Green Party parliamentary defense expert Agnieszka Brugger believes Trump is "leaving behind a pile of shrapnel because of his unilateral steps." And the parliamentary representative of the Free Democratic Party, Alexander Count Lambsdorff, believes that it is urgent to convene an extraordinary NATO summit to discuss US steps.

Meanwhile, British Defense Minister Gavin Williamson said that the United Kingdom supports the decision to withdraw from the INF Treaty made in Washington. As the head of the defense department said, London supports its closest ally, the United States, and considers it necessary to make it clear to Moscow that it must “comply with the agreement that it signed.” What exactly Williamson believes is Russia's violation of the treaty remains unclear. At the same time, he emphasized that, in general, “I would like the agreement to continue to operate.”

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

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

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

Between outside and inner ear there is a tympanic cavity. Its volume is about 2 cm3. It is lined with mucous membrane, filled with air and contains a number of important elements. Inside the tympanic cavity there are three auditory ossicles: the malleus, the incus and the stirrup, so named for their resemblance to the indicated objects (Fig. 3). The auditory ossicles are connected to each other by movable joints. The hammer is the beginning of this chain; it is woven into the eardrum. The anvil occupies a middle position and is located between the malleus and stapes. The stapes is the final link in the chain of auditory ossicles. On inside The tympanic cavity has two windows: one is round, leading into the cochlea, covered by a secondary membrane (unlike the already described tympanic membrane), the other is oval, into which a stapes is inserted, as if in a frame. Average weight malleus - 30 mg, incus - 27 mg, and stapes - 2.5 mg. The malleus has a head, a neck, a short process and a handle. The handle of the hammer is woven into the eardrum. The head of the malleus is connected to the incus joint. Both of these bones are suspended by ligaments from the walls of the tympanic cavity and can move in response to vibrations of the eardrum. When examining the tympanic membrane, a short process and the handle of the malleus are visible through it.

Rice. 3. Auditory ossicles.

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

The anvil has a body, short and long processes. With the help of the latter, it is connected to the stirrup. The stirrup has a head, a neck, two legs and a main plate. The handle of the malleus is woven into the eardrum, and the footplate of the stapes is inserted into the oval window, thereby forming a chain of auditory ossicles. Sound vibrations spread from the eardrum to the chain of auditory ossicles, forming a lever mechanism.

There are six walls in the tympanic cavity; The outer wall of the tympanic cavity is mainly the eardrum. But since the tympanic cavity extends upward and downward beyond the tympanic membrane, bone elements, in addition to the tympanic membrane, also participate in the formation of its outer wall.

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

The posterior wall borders the pneumatic system of the mastoid process (antrum and cells of the mastoid process). IN back wall The descending part of the facial nerve passes through the tympanic cavity, from which the auricular string (chorda tympani) departs here.

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

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

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

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

Mastoid temporal bone located behind auricle and external auditory canal.

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

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

The upper border of the mastoid process is the temporal line - a protrusion in the form of a roller, which is like a continuation of the zygomatic process. In most cases, the floor of the middle cranial fossa is located at the level of this line. On inner surface mastoid process, which faces the posterior cranial fossa, there is a grooved depression in which the sigmoid sinus is located, the abducens venous blood from the brain to the bulb of the jugular vein.

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