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MIDDLE EAR

The middle ear, auris media, includes the tympanic cavity with its contents, the airways of the mastoid process and the auditory tube. The tympanic cavity is separated from the external auditory meatus by the eardrum. There are auditory ossicles in it, transmitting sound vibrations to the ear labyrinth, and the muscles that regulate their position. Behind, the tympanic cavity opens into the antrum, the permanent large cell of the mastoid process, associated with its numerous small cells. A closed middle ear air system is ventilated by periodically opening the auditory tube connecting the tympanic cavity with the nasopharynx.

The eardrum, membrana tympani (Fig. 1.1.2), separates the outer ear from the middle one. This is a fairly strong fibrous translucent rounded plate with a diameter of 9-11 mm and a thickness of 0.1 mm. On 3/4 of its circumference, the membrane is fixed by a fibro-cartilaginous ring, annulus fibrocartilagineus or annulus tympanicus, in the tympanic sulcus, sulcus tympanicus, the tympanic part of the temporal bone. In the upper section, the tympanic membrane is devoid of a fibrous ring and attaches directly to the temporal bone scales in the tympanic incisura tympanica (Rivini). Most of the tympanic membrane, having anulus tympanicus, is stretched, pars tensa, and the upper part, corresponding to the tympanum, without anulus tympanicus, is relaxed, pars flaccida, or shrapnel membrane, membrana shrapnelli.

Fig. 1.1.2

The eardrum in an adult in relation to the axis of the ear canal is oblique. It is formed by a horizontal plane with an angle of 450, open to the lateral side, and with a median plane, an angle of the same size, open to the rear. In connection with this position, the membrane is a continuation of the upper wall of the external auditory canal. Approximately in the center, it is pulled into the tympanic cavity up to 2 mm. In this place, a depression forms, the so-called navel - umbo membranae tympani. With otoscopy in the form of a cone emanating from the navel of the eardrum anteriorly and downward, a reflection of the light beam incident perpendicular to the eardrum is noticeable. This light flare was called the light cone or light reflex. Shortening, moving or disappearing it indicates retraction, protrusion, cicatricial changes or inflammation of the eardrum.

The eardrum consists of three layers. Its fibrous base is represented by two layers of fibers: the outer one with the radial orientation of the beams, and the inner one with their circular arrangement. Circular fibers at the periphery pass into the fibrous-cartilage ring, annulus tympanicus, inserted into the tympanic sulcus, sulcus tympanicus. Radial connective tissue fibers attached to the membrane of the handle of the hammer. The unstretched part of the tympanic membrane does not have a fibrous layer. The outer layer of the eardrum is a continuation of the skin of the ear canal, covered with the epidermis. From the inside, the membrane is lined with a mucous membrane with a flat epithelium.

For convenience, describing the localization of pathological changes in the eardrum, it is conditionally divided into four quadrants by two mutually perpendicular lines passing through the navel. One of the lines is located along the handle of the malleus. These quadrants were named according to their localization: front-top, front-bottom, back-top, back-bottom (Fig. 1.1.2A).

The tympanic cavity, cavum tympani, is the space located between the eardrum, the external auditory canal and the labyrinth. It contains a movable chain of miniature auditory ossicles, including a malleus, anvil, stirrup and their ligamentous apparatus. In addition, in the tympanic cavity are the aural muscles, blood vessels and nerves. The walls of the tympanic cavity and the ligaments contained in it, the muscles are covered with a mucous membrane with a flat epithelium. The volume of the tympanic cavity is 1-2 cm3. Its sizes vary. The distance between the medial and lateral walls of the tympanum in the anteroposterior region is approximately 3 mm. In the back, it ranges from 5.5-6.5 mm. This is of practical importance: it is recommended that paracentesis be performed in the posterior lower quadrant of the eardrum, where there is less risk for damage to the wall of the labyrinth.

Six walls are distinguished in the tympanic cavity, schematically depicted in Fig. 1.1.3.

Fig. 1.1.3

The lateral wall of the tympanum is membranous, paries membranaceus, consists of the tympanic membrane and the bones of the external auditory canal framing it.

On the inner surface of the eardrum there are folds and pockets (Fig. 1.1.4). Between the unstretched part of the eardrum and the neck of the malleus is the upper pocket, recessus membranae tympani superior, or the Prussian space. To the top and bottom of the Prussian space are the front and back pockets of the eardrum (Trelcha's pockets). The front pocket, recessus membranae tympani anterior, is the space between the tympanic membrane and the anterior malleus fold. The back pocket, recessus membranae tympani posterior, is the space between the tympanic membrane and the posterior hammer fold. These narrow spaces during surgical interventions require compulsory revision in order to avoid relapse in chronic epithympanitis.

Fig. 1.1.4

The front wall of the tympanic cavity - carotid, paries caroticus, (Fig. 1.1.3) is present only in the lower half of the tympanic cavity. Above it is the tympanic mouth of the auditory tube. In this area there are digestions, the presence of which can lead to injury to the carotid artery with improperly performed paracentesis.

The lower wall of the tympanic cavity - the jugular, paries jugularis, (Fig. 1.1.3; 1.1.4), is the bottom of the tympanic cavity. The bottom of the middle ear cavity is located 2.5-3 mm below the corresponding lower edge of the eardrum. In inflammatory diseases, exudate can accumulate in the deepening of the middle ear cavity, recessus hypotympanicus, without falling into the doctor's field of vision. Under the bone bottom of this depression is the bulb of the internal jugular vein, bulbus venae jugularis internae. Sometimes the bulb is located directly under the mucous membrane of the tympanic cavity and can protrude into the cavity of the middle ear. Digestion of the lower wall is often found, in connection with this, cases of injury to the bulb of the internal jugular vein during paracentesis are described.

The posterior wall of the tympanum is mastoid, paries mastoideus, (Fig. 1.1.3) contains a bone pyramidal elevation, eminentia pyramidalis, inside which the stirrup muscle, m.stapedius, is placed. To the top and bottom of the pyramidal elevation there is a hole through which the drum string, chorda tympani, enters the tympanum. In the depths of the posterior wall of the tympanum behind the pyramidal elevation lies the descending part of the facial nerve, n.facialis. Above in the back wall opens the entrance to the cave, aditus ad antrum.

The medial wall of the tympanic cavity - the labyrinth, paries labyrinticus, (Fig. 1.1.5) separates the middle ear from the inner one.

Figure 1.1.5

The cape is formed by the lateral wall of the main scroll of the cochlea. On the surface of the cape there are grooves, which in a number of places, deepening, create bone channels. The nerves of the tympanic plexus, plexus tympanicus, pass through them. In particular, a thin groove stretches from top to bottom, in which there is a tympanic nerve, n.tympanicus (Jacobsoni), extending from the glossopharyngeal nerve (IX pair).

In the area of ​​the posterior-lower edge of the cape there is a hole leading to the round window of the cochlea, fenestra cochleae. The niche of the round window opens towards the back wall of the tympanic cavity. The posterior-upper part of the cape takes part in the formation of the oval window of the vestibule, fenestra vestibuli. The length of the oval window is 3 mm, the width reaches 1.5 mm. In the oval window with the help of an annular ligament, the base of the stapes is fixed. Directly above the oval window in the osseous fallopian canal, the facial nerve passes, and above and behind the protrusion of the lateral semicircular canal. Anterior to the oval window is the tendon of the muscle straining the eardrum, m.tensoris tympani, bending through the cochlear process, processus cochleariformis.

The upper wall - the roof of the tympanic cavity, paries tegmentalis, (Fig. 1.1.3-1.1.5) delimits the cavity from the bottom of the middle cranial fossa. This is a thin bone plate, which may have digestions, due to which the dura mater is in direct contact with the mucous membrane of the tympanic cavity, which contributes to the development of intracranial complications in otitis media.

The drum cavity is usually divided into three sections (Fig. 1.1.4; 1.1.5).

1. The upper section, epitympanum, is the drum cavity or attic, atticus, (attic - the term is used from architecture).

2. The middle section, mesotympanum, - the tympanic sinus, sinus tympanicus, corresponds to the stretched part of the tympanic membrane.

3. The lower section, hypotympanum, - the drum recess, recessus hypotympanicus, lies below the level of the eardrum.

In the attic, the head of the malleus and the body of the anvil are fixed on the ligaments. In front, under the attic's roof, through the rocky-tympanic fissure, fissura petrotympanica, passes the drum string, chorda tympani. On the medial wall of the attic there is an elevation of the facial nerve canal and a protrusion formed by the lateral semicircular canal. The mucous membrane, covering the bones and ligaments, forms many communicating pockets. Inflammation in this area causes pronounced morphological changes leading to bone caries. Very often, along with the attic, the antrum is involved in the pathological process, communicating with it through aditus ad antrum.

In the middle and lower parts of the tympanic cavity, two sines are distinguished - the tympanic and facial. The drum sinus is located under the pyramidal elevation and extends to the bulb of the internal jugular vein and the cochlea window. The facial sinus is bounded on the medial side by the channel of the facial nerve, behind the pyramidal elevation and in front of the cape.

The contents of the tympanum are the auditory ossicles, ossicula auditus, and the auricular. muscles (Fig. 1.1.4; 1.1.5).

The malleus, malleus, consists of a handle attached to the eardrum, a neck separated from the membrane by the airspace of Prussac, and a head located in the attic, where it connects to the anvil body. The anterior process, processus anterior, is a thin sharp protrusion from the neck of the malleus. For this process of the malleus, the anterior malleus ligament is attached to the edges of the stony-tympanic fissure. The front and back ligaments of the hammer are, as it were, brushed in a drum tenderloin. These ligaments are the axis of its rotation. From the roof of the tympanic cavity to the head of the malleus is the upper ligament of the malleus. The lateral ligament of the malleus is stretched between the incissura tympanica and the neck of the malleus. The joint between the anvil and the hammer is called the anvil-hammer joint, which has a thin capsule.

Anvil, incus. The body of the anvil is in the drum space. The short process of the anvil, crus breve, is located in the bone cavity, fossa incudis, located below the protrusion of the lateral semicircular canal and is directed to aditus ad antrum. The long process of the anvil, crus longum, extends parallel to the handle of the malleus. Its lower end makes a turn inward, forming an articulation with a stirrup. Anvil-articulation is characterized by a large volume of movements.
The anvil has two ligaments - the posterior one, attached to the short process, and the upper one, which descends from above and attaches to the body of the anvil.

The stirrup, stapes, has a head, caput stapedis, legs, crura stapedis, and a base, basis stapedis. The latter is covered with cartilage, which through an annular ligament connects to the cartilaginous edge of the oval window. The ring-shaped ligament performs a dual function: it closes the gap between the base of the stirrup and the edge of the window and at the same time provides mobility of the stirrup.

The muscle straining the eardrum, m.tensor tympani, begins in the cartilage of the auditory tube. The half-channel of this muscle passes directly above the bone part of the auditory tube, parallel to the last. Both channels are separated by a very thin partition. Upon exiting the semicanal, the tendon of m.tensoris tympani makes a turn around a small hook-shaped protrusion on the cape - the cochlear process, processus cochleariformis. Then the tendon crosses the tympanic cavity in the lateral direction and is attached to the handle of the malleus near the neck.

The stapedius muscle, m.stapedius, lies in the cavity of the bone pyramidal elevation - eminentia pyramidalis, in the posterior wall of the tympanic cavity. Her tendon comes out through the hole in the apex of this protrusion and is attached to the neck of the stapes.

Morphological elements of the walls of the tympanic cavity and its contents are projected onto different quadrants of the tympanic membrane (Figure 1.1.2A), which should be taken into account during otoscopy and manipulations.

The front-upper quadrant corresponds to: the upper segment of the opening of the auditory tube, the closest part of the labyrinth wall of the tympanic cavity, the cochlear process and the part of the facial nerve located behind it.

The front-lower quadrant corresponds to: the lower segment of the tympanic opening of the auditory tube, the adjacent part of the front-lower wall of the tympanic cavity and the front of the cape.

The back-upper quadrant corresponds to: the handle of the malleus, the long process of the anvil, the stirrup with an oval window, a pyramidal elevation and the tendon of the stirrup muscle behind it. Above the junction between the anvil and the stirrup is a drum string.

The back-lower quadrant corresponds to the niche of the round window and the adjacent part of the lower wall of the tympanic cavity. This is the safest place for paracentesis and puncture of the tympanic membrane, since the niche of the round window is covered with a dense bone of the cape.

The air-bearing cells of the mastoid process, cellulae mastoideae, (Fig. 1.3; 1.4) are formed as it grows. The newborn has no mastoid process, and there is only the mastoid part of the tympanic ring, in which the cave is located, antrum communicating with the tympanic cavity through the cave entrance, aditus ad antrum, in the upper part of its posterior wall. Its volume is up to 1 cm3. In a newborn, the antrum is located above the temporal line, linea temporalis, at a depth of 2-4 mm under the cortical layer. The mastoid process begins to develop towards the end of the first year of life, after the sternocleidis is strengthened and the baby begins to hold its head. The antrum drops below the temporal line, located under the site of the appendix planum mastoideum, at a depth of 1.5-2 cm, and small air cells (cells) of the appendix are formed from it. Pneumatization is mainly completed by 5-7 years. There are pneumatic, diploetic, mixed (normal) and sclerotic (pathological) types of structure of the mastoid process. With severe pneumatization, periantral, apical, perisinous, perilabirint, perifacial, angular, zygomatic, and other groups of cells are distinguished. The topography and development of the cellular structure of the mastoid must be taken into account in the diagnosis of purulent ear diseases and the choice of surgical access to the antrum.

On the inner surface of the mastoid process, facing the posterior cranial fossa, a sigmoid sinus, sinus sigmoideus, is placed. It is a continuation of the transverse sinus, sinus transversus. Coming out of the mastoid part, the sigmoid sinus under the bottom of the tympanum forms an expansion - the bulb of the jugular vein. Presentation of the sinus (close proximity to the auditory meatus) or lateral position (superficial location) pose a risk of injury from an anthrotomy of radical ear surgery.

The auditory tube, tuba auditiva, (Eustachian tube) connects the tympanic cavity with the nasopharynx (Fig. 1.1.2-1.1.4). The tympanic orifice, ostium tympanicum tubae auditivae, 4-5 mm in diameter, occupies the upper half of the anterior wall of the tympanum. The pharyngeal orifice of the auditory tube, ostium pharyngeum tubae auditivae, oval in diameter, 9 mm, is located on the lateral wall of the nasopharynx, at the level of the posterior end of the inferior nasal concha and has an elevated posterior-upper margin - torus tubarius. In the area of ​​the pharyngeal opening of the auditory tube, there is an accumulation of lymphoid tissue called the tonsil, tonsilla tubaria.

In an adult, the tympanic opening is approximately 2 cm above the pharyngeal, as a result of which the auditory tube is directed downward, inward and anteriorly towards the pharynx. The length of the pipe is 3.5 cm. In children, it is wider, straighter, shorter than in adults and is located more horizontally.

The tympanic part of the auditory tube, its component 1/3, is the bone, and the pharyngeal - membranous-cartilaginous. The cartilage has the form of a gutter to which the movable connective tissue membrane fits tightly inside. The walls of the tube in the membranous-cartilaginous part are in a collapsed state. At the junction of the bone part in the membranous-cartilaginous isthmus with a diameter of 2-3 mm.

During swallowing, chewing and yawning, the auditory tube opens due to the contraction of the muscles straining the palate, m.tensoris veli palatini and raising the soft palate, m.levator veli palatini. The muscles are attached to the connective tissue membrane that makes up the lateral wall of the membrano-cartilaginous part of the tube. The tube-pharyngeal muscle, m.salpingopharyngeus, which attaches to the pharyngeal opening of the tube, also participates in the opening of the lumen of the tube. Violation of the patency of the pipe, its gaping, the development of the valve mechanism, etc. leads to persistent functional disorders.

Слизистая оболочка слуховой трубы выстлана мерцательным эпителием и имеет большое количество слизистых желез. Движение ресничек направлено в сторону носоглотки. Все это обеспечивает защитную функцию. Тем не менее, слуховая труба является основным путем инфицирования уха.

Кровоснабжение среднего уха осуществляется из системы наружной и отчасти – внутренней сонной артерий.

К бассейну наружной сонной артерии относятсяся: a.stylomastoidea, a.tympanica anterior из a.maxillaris, a.tympanica inferior a.pharingea ascendens, ramus petrosus и a.tympanica superior – ветви a.meningeae mediae от a.maxillaris. От внутренней сонной артерии ответвляются aacaroticotympanicae.

Венозный отток осуществляется в plexus pterigoideus, sinus petrosus superior, v.meningea media, bulbus v.jugularis и plexus caroticus.

Лимфа дренируется в nodi lymphatici retropharyngeales, nodi lymphatici parotidei и nodi lymphatici cervicales profundi.

Иннервация среднего уха. В слизистой оболочке барабанной полости имеется барабанное сплетение, plexus tympanicus, распространяющееся в слизистую оболочку слуховой трубы и сосцевидной пещеры. Это сплетение образовано чувствительными разветвлениями барабанного нерва, n.tympanicus, - ветви языкоглоточного нерва, n.glossopharingeus (IX пара), содержащего так же вегетативные (секреторные) волокна. Последние выходят из барабанной полости под названием малого каменистого нерва, n.petrosus minor, через одноименную расщелину. Они прерываются в ушном узле, ganglion oticum, и иннервируют околоушную слюнную железу. В образовании барабанного сплетения также участвуют соннобарабанные нервы, nncaroticotympanici, отходящие от симпатического сплетения внутренней сонной артерии. M. tensor tympani иннервируется одноименным нервом от третьей ветви тройничного нерва (V пара). Стременная мышца получает иннервацию от лицевого нерва (VII пара).

Лицевой нерв, n. facialis, (VII пара) имеет сложный ход в височной кости (рис. 1.1.3, 1.1.4) и снабжает двигательной иннервацией стременную мышцу и мимическую мускулатуру лица. С ним в височной кости проходит промежуточный нерв, n.intermedius (XIII пара), обеспечивающий вкусовую чувствительность передних 2/3 языка. В мостомозжечковом углу нервы входят во внутренний слуховой проход и следуют до его дна всместе с n. vestibulocochlearis (VIII пара). Далее 3 мм они идут внутри пирамиды височной кости рядом с лабиринтом (лабиринтный отдел). Здесь от секреторной порции лицевого нерва отходит большой каменистый нерв, n.petrosus major, иннервирующий слезную железу, а также слизистые железы полости носа. Перед выходом в барабанную полость имеется коленчатый ганглий, ganglion geniculi, в котором прерываются вкусовые чувствительные волокна промежеточного нерва. Место перехода лабиринтного отдела в барабанный обозначается как первое колено лицевого нерва. В барабанной полости (барабанный отдел) 10-11 мм лицевой нерв вместе с промежуточным следуют в тонкостенном костном фаллопиевом канале сначала горизонтально спереди назад по медиальной стенке барабанной полости, а затем изгибаются вниз к пирамидальному выступу и переходят на заднюю стенку барабанной полости. В этом втором колене нервный ствол лежит непосредственно под нижнемедиальной стенкой входа в пещеру. Здесь он чаще всего травмируется при операциях. Нисходящий участок канала от пирамидального выступа до шилососцевидного отверстия, foramen stylomastoideum (сосцевидный отдел) имеет длину 12-13,5 мм. В пирамидальный выступ к стременной мышце от лицевого нерва отходит n.stapedius, а ниже его в барабанную полость входит барабанная струна. В составе барабанной струны, chorda tympani, идут промежуточный нерв и секреторные парасимпатические волокна лицевого нерва для подчелюстной и подъязычной слюнных желез. После выхода из шилососцевидного отверстия, лицевой нерв распадается на конечные ветви в виде “гусиной лапки”, pes anserinos, и иннервирует мышцы лица.

Знание уровня отходждения веточек лицевого и промежуточного нервов (рис. 1.1.6) позволяет проводить топическую диагностику их поражения. Периферический паралич лицевого нерва отмечается при его патологии ниже уровня отхождения барабанной струны (I). При повреждении барабанной струны (II) нарушается вкус на передних 2/3 языка и уменьшается выделение слюны.Повреждение лицевого нерва над пирамидальным выступом (III) к этим симптомам добавляет слуховую гиперэстезию – гиперакузис. Поражение лабиринтного отдела (IV) дополнительно обусловливает сухость глаза. Сдавление пучка невриномой VIII нерва во внутреннем слуховом проходе (V) наряду со всеми указанными симптомами ведет к снижению слуха и вестибулярным рассторойствам, но без гиперакузиса, так как он не проявляется при пониженном слухе.

Fig. 1.1.6

При центральном надъядерном парезе лицевой мускулатуры в отличие от периферического страдают не все мимические мышцы. Верхние мимические мышцы (m.frontalis, m.orbicularis oculi et m.corrygator supercilii) почти не страдают, так как верхние отделы двигательных ядер лицевого нерва получают двустороннюю корковую иннервацию, а нижние – лишь с противоположного полушария. Следовательно, при центральном параличе страдают нижние мышцы лица и сохраняется функция верхних мышц.
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СРЕДНЕЕ УХО

  1. НАРУЖНОЕ И СРЕДНЕЕ УХО
    Как можно убедиться, в преобразовании звуковых волн в электрические импульсы нет ничего таинственного. Согласно одной из точек зрения, слух - это не что иное, как развитое до совершенства чувство давления. Звуковые волны с определенной периодичностью оказывают давление на предметы, с которыми встречаются на пути своего распространения. Это давление очень мало в обычных условиях, и единичная
  2. INNER EAR
    The inner ear, auris interna, or labyrinth, labirinthus, is located in the depths of the pyramid of the temporal bone and consists of several intricately constructed cavities and channels that communicate with each other. A bone labyrinth or labyrinth capsule and the connective tissue or membranous labyrinth contained in it are isolated. The bony labyrinth, labyrinthus osseus, (Fig. 1.1.7) has walls consisting of
  3. INNER EAR
    On the other side of the oval window, at the foot of the stepladder, there is a vestibule. The vestibule and the formations inside it are filled with a fluid that, in consistency, resembles a cerebrospinal fluid. Here, sound waves are finally transformed from air vibrations to fluid vibrations. The hearing organs of primitive vertebrates were adapted precisely to the liquid medium, and, in fact
  4. НАРУЖНОЕ УХО
    Наружное ухо,auris externa,состоит из ушной раковины и наружного слухового прохода. Ушная раковина, auricula, (рис. 1.1.1), в своей основе имееет сложной формы эластический хрящ-cartilago auriculae, покрытый кожей. В нижней трети хрящ отсутсвует. Складка кожи, заполненная жировой тканью, образует ушную дольку, lobulus auriculae, (мочку). При воспалении хряща ушной раковины
  5. УХО
    УХО
  6. УХО
    УХО
  7. Помощь при попадании инородных тел в ухо, нос, глаза и дыхательные пути
    Инородные тела наружного слухового прохода. Различают два вида инородных тел — живые и неживые. Живые — это насекомые (клопы, тараканы, мошки, мухи и др.), неживые — мелкие предметы (пуговицы, бусины, горох, косточки от ягод, семечки, куски ваты и др.), которые попадают в наружный слуховой проход. Неживые инородные тела, как правило, не вызывают никаких болевых ощущений и нахождение их в ухе
  8. Middle ear inflammation acute
    Cause Penetration of various microorganisms into the middle ear: staphylococci, streptococci, viruses and fungi. Most often, microorganisms penetrate the middle ear through the auditory tube, which can be promoted by inflammatory processes in the nasal passage, paranasal sinuses, and nasopharynx. Infection in the middle ear can get through the external auditory canal when the tympanic membrane ruptures. At
  9. Анатомия среднего уха
    Среднее ухо (auris media) состоит из нескольких сообщающихся между собой воздухоносных полостей: барабанной полости (cavum tympani), слуховой трубы (tuba auditiva), входа в пещеру (aditus ad antrum), пещеры (antrum) и связанных с нею воздухоносных ячеек сосцевидного отростка (cellulae mastoidea). Посредством слуховой трубы среднее ухо сообщается с носоглоткой; в нормальных условиях это
  10. Отит средний
    Воспаление среднего уха — самое частое бактериальное заболевание детей — вызывают пневмококки, гемолитические стрептококки, гемофиль-ная палочка, реже стафилококки, обычно на фоне ОРВИ. В России эти возбудители обычно чувствительны к антибиотикам, но при повторных отитах часто устойчивы к препаратам первого выбора. КЛИНИЧЕСКАЯ КАРТИНА Симптомы: «беспричинное» повышение температуры, боли в ухе,
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