Clinical anatomy of the inner ear. Blood supply to the outer ear

The human ear consists of three sections: external, middle and internal(Fig. 5.1). First of all, already in the 4th week of intrauterine development, the formation of the rudiment begins inner ear. Initially, it appears as a limited thickening of the ectoderm in the region of the rhombencephalon. By the 9th week of fetal development, the inner ear is already formed, but the growth of the labyrinth basically ends by the end of the first year of life. There are two types of receptors in the inner ear - cochlear (cochlear) and vestibular (statokinetic), Accordingly, the cochlear and vestibular parts of the inner ear are distinguished. Phylogenetically, the vestibular part of the inner ear is more ancient, the cochlear part develops later. The outer and middle ears begin to develop at the 5th week of intrauterine development from the 1st and 2nd gill slits. By the time of birth, the fetus already has a fully formed tympanic cavity with six walls. Its lumen is filled with myxoid tissue, which usually resolves only after 6 months and can be a good breeding ground for the development of infection.

5.1.1. Clinical anatomy of the external ear

The external ear is represented by the auricle and the external ear canal.

Auricle (auricula)(Fig. 5.2) is located between the temporomandibular joint in front and the mastoid process in the back. It is based on a plate of elastic cartilage 0.5-1 mm thick, covered on both sides with perichondrium and skin. Only

Rice. 5.1. Scheme of the structure of the peripheral auditory department: 1 - chorda tympanum (Chorda tympani);2- auditory ossicles; 3 - cells of the mastoid process (Cellula mastoidalis);4- tympanic cavity (Cavum tympani); 5 - external auditory canal (Meatus acusticus externus);6- eardrum (Membrana tympani);7- internal jugular vein (V Jugularis interna); 8 - semicircular canals (Canalis semicircularis); 9 - facial nerve (N. facialis); 10 - vestibulocochlear nerve (N. Vestibulocochlearis); 11 - snail (Cochlea); 12 - internal carotid artery (A. carotis interna); 13 - muscle that strains the velum palatine (M. tensor veli palatini); 14 - Eustachian tube (Tuba auditiva); 15 - muscle levator velum palatine (M. levator veli palatine). Blue indicates the outer ear, green indicates the middle ear, and yellow indicates the inner ear.

Rice. 5.2. Auricle: 1 - lobe; 2 - curl; 3 - stem of the helix; 4 - external auditory canal; 5 - antihelix; 6 - rook; 7 - cavity of the auricle; 8 - tragus; 9 - antitragus

lower part of the auricle - lobulus- lacks a cartilaginous skeleton and is formed by fatty tissue covered with skin. The outer surface of the auricle is concave, the skin on it is tightly fused with the perichondrium. The inner surface of the shell is convex; here the connective tissue between the skin and the perichondrium is more developed. The free edge of the auricle is presented in the form of a rounded roller - curl (helix), which begins with its crus helices above the entrance to external auditory canal (porus acusticus externus) and stretches upward, then backward and downward. Inside and parallel to the curl in the form of a roller is located antihelix (anthelix). There is a longitudinal recess between them - rook (scapha). Anterior to the antihelix there is a depression, which is designated as cavity of the auricle (cavum conchae), deepening in a funnel shape, it leads to the entrance to the external auditory canal. In front there is a protruding part of the outer ear canal - tragus, and behind there is another ledge - antitragus, below between them there is a deep tenderloin (incisura intertragica).

The human auricle is attached by ligaments and muscles to the scales of the temporal bone, mastoid and zygomatic processes,

Rice. 5.3. External ear of an adult (a) and a newborn (b): c - frontal section of the ear; 1 - external auditory canal; 2 - eardrum; 3 - tympanic cavity with auditory ossicles; 4 - auditory tube; 5 - snail; 6 - vestibule sacs; 7 - ampulla of the semicircular canal; 8 - vestibulocochlear nerve

The muscular apparatus of the shell in humans is rudimentary. Around the entrance to the external auditory canal, the skin is covered with hair (especially noticeable in older people) and contains sebaceous glands.

Direct continuation of the shell cavity (cavum conchae) is external auditory canal(Fig. 5.3 a-c), the length of which in adults is about 2.5 cm, the lumen of a round or elliptical shape has a diameter of approximately 0.7-0.9 cm. The external auditory canal in humans consists of two sections: the external membranous-cartilaginous and internal bone It ends at the eardrum, which separates the outer and middle ears. The membranous-cartilaginous section makes up two-thirds of the length of the external auditory canal, and the bony section makes up one third. The basis of the membranous-cartilaginous section is the continuation of the cartilage of the auricle, and this cartilage has the appearance of a groove, open posteriorly and upward. Its membranous part is formed by dense connective tissue, rich in elastic fibers. The cartilaginous skeleton along its length is interrupted by vertically running Santorini cracks (incisurae Santorini), covered with fibrous tissue. In the area of ​​the Santorini fissures, the auditory meatus borders below with the parotid salivary gland, and this determines the possibility of the inflammatory process transferring from the outer ear to the parotid gland and vice versa.

The membranous-cartilaginous section is connected to the bony part of the external auditory canal by dense fibrous tissue. Approximately in the middle of the bony section is the narrowest part of the external auditory canal - isthmus (isthmus). The auditory canal is somewhat curved in the horizontal and frontal planes, therefore, to examine the bone and eardrum, it is straightened by pulling the auricle backwards and upwards along with the outer part of the auditory canal. In children, during examination, the auricle is pulled back and down.

The skin in the membranous-cartilaginous section is 1-2 mm thick and contains hair, greasy and sulfur(cerumenal) glands. The latter are modified sebaceous glands. The secret of sulfur and sebaceous glands, as well as scales of rejected epidermis form earwax, which falls out of the ear canal when the walls of the membranous-cartilaginous section vibrate

at the moment of chewing. Excess sulfur and disruption of its normal evacuation leads to the formation of sulfur plug. In the bone section, the skin is devoid of hair and glands, is closely connected with the periosteum, gradually thins to 0.1 mm and passes to the eardrum in the form of epidermis.

Front wall The external auditory canal borders the joint of the lower jaw, and the movements of the jaw are transmitted to the membranous-cartilaginous part of the canal. In the presence of an inflammatory process in the area of ​​the anterior wall, chewing is accompanied by severe pain. A fall and a blow to the chin can lead to a fracture of the anterior bone wall of the ear canal.

Upper bone wall separates the external auditory canal from the middle cranial fossa. A fracture of the base of the skull in this area may be accompanied by bleeding and liquorrhea from the ear canal.

Back wall The external auditory canal separates it from the cells of the mastoid process; the facial nerve passes through the base of this wall. The superomedial section of this wall borders the anterior wall of the mastoid cave. With mastoiditis, the posterior and upper walls of the ear canal near the eardrum are involved in the process, which is manifested by their “overhang.”

Bottom wall separates the external auditory canal from the parotid salivary gland. In the bone section, the lower wall is elongated by 4-5 mm compared to the upper one.

In a newborn and in the first months of life, the external auditory canal is presented in the form of a gap due to the fact that the bone part is not developed and the upper wall is almost closely adjacent to the lower one. The eardrum of children in the first year of life forms an acute angle with the axis of the auditory canal and is located almost horizontally (Fig. 5.3 b).

Blood supply the external ear is carried out from the external carotid artery system. The auricle is supplied with blood from a. auricularis posterior u a. temporalis superficialis. These same vessels, as well as a. auricularis profunda (branch of a. maxillaries interna), supplying blood to the deeper sections and the eardrum, forming a plexus around the external auditory canal. Nutrition of the cartilage is provided from the vessels of the perichondrium.

Venous drainage- anteriorly in v. facialis posterior and posteriorly in v. auricularis posterior.

Lymph from the outer ear it flows towards the nodes located anterior to the tragus, on the mastoid process and under the lower wall of the external auditory canal. Next, the lymph enters the deep cervical lymph nodes, which, when the external auditory canal is inflamed, enlarge and become painful on palpation.

Innervation external ear is carried out by branches of the trigeminal nerve (n. auriculotemporalis - branch of n. mandibularis) and cervical plexus, as well as the auricular branch of the vagus nerve (r. auricularis n. vagi). Due to the vagal reflex, when the posterior and inferior walls of the external auditory canal are irritated, some people experience a cough. The motor innervation of the rudimentary muscles of the auricle, the functional role of which is negligible, is provided by the posterior auricular nerve - a branch of the facial nerve.

Eardrum (membrana tympani, myrinx) separates the outer and middle ear. This is a durable fibrous translucent plate, shaped like an oval, elongated from top to bottom. The vertical size of the eardrum is approximately 10 mm, width - 8-9 mm, thickness 0.1 mm, area about 55-60 mm2. In children, the size of the eardrum is almost the same as in adults, but it has a more rounded shape and is much thicker due to the thickness of the skin and mucous membrane. In relation to the axis of the external auditory canal, the eardrum is located obliquely, forming an acute angle of about 30° with the lower and anterior walls. In addition, the tympanic membrane is funnel-shaped and retracted into the tympanic cavity, so that its central section is navel (umbo)- corresponds to the place of greatest retraction. IN different areas The eardrum is unequally spaced from the inner wall of the tympanic cavity: in the center - by 1-1.5 mm, in the anterior-inferior section - by 4-5 mm, in the posterior-inferior - up to 6 mm (Fig. 5.4 a, b).

The tympanic membrane is enclosed in a groove of the fibrocartilaginous drum ring (annulus tympanicus). However, there is no groove at the top, and it is attached directly to the scales of the temporal bone in tympanic notch (incisura tympanica s. Rivini). The part of the eardrum fixed in the tympanic ring, occupying more than 90% of its area, is designated as taut her part (pars tensa), and a small area located in the region of the Rivinian notch is called loose part, or shrapnel membrane (pars flacida, s. membrana Shrapnelli).

Rice. 5.4. Microscopic structure of the eardrum (a); projection of the elements of the middle ear onto the eardrum (b)

The stretched part of the eardrum consists of three layers: outdoor- cutaneous (epidermal), internal- epithelial, which is a continuation of the mucous membrane of the tympanic cavity, and average connective tissue, represented by radial and circular fibrous fibers. The handle of the malleus is attached to the tympanic membrane by radial fibers, tightly fused with its inner and middle layers. The lower end of the hammer handle just below the middle of the eardrum forms a funnel-shaped depression - navel (umbo). The handle of the malleus continues upward and somewhat anteriorly and forms in the upper third visible from the outside short process (processus brevis), from which the anterior and posterior folds extend anteriorly and posteriorly, respectively, separating the tense and loose parts of the tympanic membrane.

Under artificial light, the eardrum has a pearlescent gray color; a number of identification points can be distinguished on its surface:

Handle;

Short shoot;

Front and back folds;

A cone of light formed by the reflection of light incident on the surface of the eardrum.

For convenience of describing the changes revealed during otoscopy, the eardrum is conventionally divided into four quadrants, formed by the intersection of a line passing along the handle of the hammer through the navel, and a perpendicular to it, also passing through the navel. Distinguish anterosuperior, posterosuperior, anterioinferior And posteroinferior quadrants. The light cone, shaped like a shiny isosceles triangle, is located in the anterior inferior quadrant.

Blood supply the eardrum comes from the side of the outer ear from a. auricularisprofunda (from a. maxillaris) and from the side of the middle ear from a. tympanica. The vessels of the tympanic membrane are located in the form of two networks: an external one, connected with the vessels of the outer ear and branching in the skin layer, and an internal one, branching in the mucous membrane of the eardrum. The vessels of the outer and inner surfaces of the eardrum anastomose with each other. Veins of the outer surface of the eardrum

They flow into the external jugular vein, the veins of the inner surface - into the plexus around the auditory tube, the transverse sinus and into the veins of the dura mater.

Lymphatic drainage carried out to the preauricular, retroauricular and posterior cervical lymph nodes. Innervation the eardrum comes from the auricular branch of the vagus nerve (r. auricularis n. vagi), as well as the tympanic branch of the glossopharyngeal nerve and n. auriculotemporal.

5.1.2. Clinical anatomy of the middle ear

The middle ear is a system of communicating air cavities:

Tympanic cavity;

Eustachian tube (tuba auditiva);

cave entrance (aditus ad antrum);

cave (antrum) and associated cells of the mastoid process (cellulae mastoidea).

The central position, both in its topographical position and in its significance in the clinical picture, is occupied by the tympanic cavity. The closed air system of the middle ear is ventilated through the auditory tube connecting the tympanic cavity with the nasopharyngeal cavity.

Tympanic cavity (cavum tympani) represents the space enclosed between the eardrum and the labyrinth. The shape of the tympanic cavity resembles an irregular tetrahedral prism with a volume of about 1 cm3, with the largest upper-lower dimension (height) and the smallest between the outer and inner walls (depth). There are six walls in the tympanic cavity (Fig. 5.5):

External and internal;

Top and bottom;

Front and back.

Outer (lateral) wall is represented by the tympanic membrane, separating the tympanic cavity from the external auditory canal, and the bone sections bordering it above and below (Fig. 5.6). Above the tympanic membrane, a plate participates in the formation of the lateral wall top wall external auditory canal with a width of 3 to 6 mm, to the lower edge of which (incisura Rivini) the eardrum is attached. Below level

Rice. 5.5. Schematic representation of the tympanic cavity (no outer wall): a - inner wall; b - front wall; c - rear wall; g - bottom wall; d - upper wall; 1 - lateral semicircular canal; 2 - facial canal; 3 - roof of the tympanic cavity; 4 - window of the vestibule; 5 - hemicanal of the tensor tympani muscle; 6 - tympanic opening of the auditory tube; 7 - canal of the carotid artery; 8 - cape; 9 - tympanic nerve; 10 - inner bulb jugular vein; 11 - cochlear window; 12 - drum string; 13 - pyramidal elevation; 14 - entrance to the cave

At the attachment of the eardrum there is also a small bone sill.

In accordance with the structural features of the lateral wall, the tympanic cavity is conventionally divided into three sections: upper, middle and lower.

Upper section - epitympanic space, attic, or epitympanum - located above the upper edge of the stretched part of the eardrum. Its lateral wall is the bony plate of the upper wall of the external auditory canal

Rice. 5.6. Lateral (outer) wall of the tympanic cavity: 1 - supratympanic recess; 2 - superior ligament of the malleus; 3 - hammer handle; 4 - eardrum; 5 - tympanic opening of the auditory tube; 6 - knee of the internal carotid artery; 7 - second (vertical) knee of the facial nerve; 8 - drum string; 9 - anvil

And pars flaccida eardrum. In the supratympanic space there is an articulation between the malleus and the incus, which divides it into external and internal sections. In the lower part of the outer section of the attic, between pars flaccida The tympanic membrane and the neck of the malleus are the superior recess of the mucous membrane, or Prussian's space. This narrow space, as well as the anterior and posterior pockets of the tympanic membrane (Treltsch's pouches) located downward and outward from the Prussian space, require mandatory revision during surgery for chronic epitympanitis in order to avoid relapse.

Middle section of the tympanic cavity - mesotympanum - largest in size, corresponds to the projection pars tensa eardrum.

Lower section (hypotympanum)- a depression below the level of attachment of the eardrum.

Medial (internal, labyrinthine, promontorial) the wall of the tympanic cavity separates the middle and inner ear (Fig. 5.7). In the central section of this wall there is a protrusion - a promontory, or promontorium, formed by the lateral wall of the main curl of the cochlea. The tympanic plexus is located on the surface of the promontorium (plexus tympanicus). The tympanic (or Jacobson) nerve participates in the formation of the tympanic plexus (n. tympanicus - branch n. glossopharyngeus), nn. trigeminus, facialis, as well as sympathetic fibers from plexus caroticus internus.

Behind and above the cape is vestibule window niche (fenestra vestibuli), shaped like an oval, elongated in the anteroposterior direction, measuring 3 by 1.5 mm. The vestibule window is closed base of the stirrup (basis stapedis), attached to the edges of the window

Rice. 5.7. The medial wall of the tympanic cavity and the auditory tube: 1 - promontory; 2 - stirrup in the niche of the window of the vestibule; 3 - cochlear window; 4 - first knee of the facial nerve; 5 - ampulla of the lateral (horizontal) semicircular canal; 6 - drum string; 7 - stapedius nerve; 8 - jugular vein; 9 - internal carotid artery; 10 - auditory tube

by using annular ligament (lig. annulare stapedis). In the area of ​​the posterior-inferior edge of the promontory there is snail window niche (fenestra Cochleae), protracted secondary eardrum (membrana tympani secundaria). The window niche of the cochlea faces the posterior wall of the tympanic cavity and is partially covered by the projection of the posteroinferior slope of the promontorium.

Directly above the window of the vestibule in the bony fallopian canal there passes the horizontal knee of the facial nerve, and above and posteriorly there is a protrusion of the ampulla of the horizontal semicircular canal.

Topography facial nerve (n. facialis, VII cranial nerve) has important practical significance. Joining with n. statoacousticus And n. intermedius into the internal auditory canal, the facial nerve passes along its bottom, in the labyrinth it is located between the vestibule and the cochlea. In the labyrinthine section, it departs from the secretory portion of the facial nerve greater stony nerve (n. petrosus major), innervating the lacrimal gland, as well as the mucous glands of the nasal cavity. Before exiting into the tympanic cavity, above the upper edge of the window of the vestibule there is geniculate ganglion (ganglion geniculi), in which the taste sensory fibers of the intermediate nerve are interrupted. The transition of the labyrinthine section to the tympanic section is designated as first genus of the facial nerve. The facial nerve, having reached the protrusion of the horizontal semicircular canal on inner wall, at the level pyramidal eminence (eminentia pyramidalis) changes its direction to vertical (second knee) passes through the stylomastoid canal and through the foramen of the same name (for. stylomastoideum) extends to the base of the skull. In the immediate vicinity of the pyramidal eminence, the facial nerve gives off a branch to stapedius muscle (m. stapedius), here it departs from the trunk of the facial nerve drum string (chorda tympani). It passes between the malleus and the incus through the entire tympanic cavity from above the eardrum and exits through fissura petrotympanica (s. Glaseri), giving taste fibers to the anterior 2/3 of the tongue on its side, secretory fibers to the salivary gland and fibers to the choroid plexuses. The wall of the facial nerve canal in the tympanic cavity is very thin and often has dehiscence, which determines the possibility of inflammation spreading from the middle ear to the nerve and the development of paresis or even paralysis of the facial nerve. Various locations of the facial nerve in the tympanic and mastoid

its departments should be taken into account by the otosurgeon so as not to injure the nerve during the operation.

Located anteriorly and above the window of the vestibule snail-shaped protrusion - proc. cochleariformis, through which the tendon of the tensor tympani muscle bends.

Front wall tympanic cavity - tubal or carotid (paries tubaria s. caroticus). The upper half of this wall is occupied by two openings, the larger of which is the tympanic opening of the auditory tube. (ostium tympanicum tubae auditivae), above which the hemicanal of the tensor tympani muscle opens (m. tensor tympani). In the lower section, the anterior wall is formed by a thin bone plate separating the trunk of the internal carotid artery, passing in the canal of the same name. This wall is penetrated by thin tubules through which vessels and nerves pass into the tympanic cavity, and the inflammatory process can move from the tympanic cavity to the carotid artery.

Posterior wall of the tympanic cavity- mastoid (paries mastoideus). In its upper section there is a wide passage (aditus ad antrum), through which the epitympanic space communicates with cave (antrum mastoideum)- permanent cell of the mastoid process. Below the entrance to the cave, at the level of the lower edge of the window of the vestibule, on the back wall of the cavity there is pyramidal eminence (eminentia pyramidalis), containing m. stapedius the tendon of which protrudes from the top of this elevation and is directed to the head of the stapes. Outside the pyramidal eminence there is a small hole from which the drum string emerges.

The upper wall is the roof of the tympanic cavity (tegmen tympani). This is a bone plate with a thickness of 1 to 6 mm, separating the tympanic cavity from the middle cranial fossa. Sometimes there are dehiscences in this plate, due to which the dura mater of the middle cranial fossa is in direct contact with the mucous membrane of the tympanic cavity. This may contribute to the development of intracranial complications in otitis media. In children of the first years of life, at the border of the stony and scaly parts of the temporal bone in the area of ​​the roof of the tympanic cavity there is an unfused fissura petrosquamosa, which makes it possible for brain symptoms (meningismus) to occur in acute otitis media. Subsequently, a seam is formed at the site of this gap - sutura petrosquamosa.

The lower wall of the tympanic cavity- jugular (paries jugularis)- borders on the underlying bulb of the jugular vein (bulbus venae juggle). The bottom of the cavity is located 2.5-3 mm below the edge of the eardrum. The more the jugular vein bulb protrudes into the tympanic cavity, the more convex the bottom is and the thinner it is. Sometimes bone defects are observed here - dehiscence, then the bulb of the jugular vein protrudes into the tympanic cavity and can be injured when performing paracentesis.

The mucous membrane of the tympanic cavity is a continuation of the mucous membrane of the nasopharynx and is represented by a single-layer squamous and transitional ciliated epithelium with a few goblet cells. Covering the auditory ossicles and ligaments, the mucous membrane forms many communicating pockets and sinuses. The two most significant clinically are the tympanic and facial sinuses. The tympanic sinus lies beneath the pyramidal eminence and extends to the jugular bulb and fenestra cochlea. The facial sinus is limited by the medial canal of the facial nerve, posteriorly by the pyramidal eminence, and anteriorly by the promontory.

The tympanic cavity contains three auditory ossicles and two intraauricular muscles. The chain of auditory ossicles (Fig. 5.8) are interconnected joints:

Rice. 5.8. Auditory ossicles:

1 - hammer; 2 - anvil; 3 - stirrup

* malleus (malleus);

* anvil (incus);

* stirrup (stapes).

The handle of the malleus is woven into the fibrous layer of the tympanic membrane, the base of the stapes is fixed in the niche of the window of the vestibule. The main array of auditory ossicles - the head and neck of the malleus, the body of the incus - are located in the supratympanic space. The malleus is distinguished by a handle, neck and head, as well as anterior and lateral processes. The manubrium and lateral process are visible when examining the tympanic membrane. The mass of the hammer is about 30 mg. The anvil consists of a body, short and long processes. A short process is located at the entrance to the cave. Through a long process, the incus is articulated with the head of the stapes. The mass of the anvil is 27 mg. The stirrup has a base, two legs, a neck and a head. The annular ligament, with the help of which the base of the stapes is attached to the edge of the window of the vestibule, is quite elastic and provides good mobility mainly of the anterior sections of the base of the stapes. The mass of the stapes is about 2.5 mg, the base area is 3-3.5 mm2. The auditory ossicles are connected to each other through joints that ensure their mobility; There are a number of ligaments that support the entire chain of auditory ossicles.

Two intraauricular muscles carry out movements of the auditory ossicles, providing accommodation and protective functions. The tendon of the tensor tympani muscle is attached to the neck of the malleus - m. tensor tympani. This muscle begins in the bony hemicanal above the tympanic opening of the auditory tube. Its tendon is initially directed from front to back, then bends at a right angle through the cochlear-shaped protrusion, crosses the tympanic cavity in the lateral direction and attaches to the malleus. M. tensor tympani innervated by the mandibular branch of the trigeminal nerve.

Stapedius muscle located in the bony sheath of the pyramidal eminence, from the opening of which at the apex the muscle tendon emerges, in the form of a short trunk it goes anteriorly and is attached to the head of the stapes. Innervated by a branch of the facial nerve - n. stapedius

Auditory (Eustachian) tube (tuba auditiva)(see Fig. 5.1) provides communication between the tympanic cavity and the external environment. Auditory

the tube is 3.5 cm long in adults; in children it is shorter, wider and more horizontal. It consists of two sections - short bone (pars ossea) and longer membranous-cartilaginous (pars cartilaginea), where the cartilage is presented in the form of a groove covered with mucous membrane. The sections of the auditory tube form an obtuse angle between themselves, open downwards. At the point of transition of the cartilaginous part of the tube into the bone, the narrowest place is located - isthmus (isthmus)

1-1.5 mm in diameter. The tympanic orifice of the auditory tube with a diameter of 4-5 mm is located in the upper part of the anterior wall of the tympanic cavity. The pharyngeal opening of the auditory tube lies 1-2.5 cm below the tympanic, opens on the lateral wall of the nasopharynx, at the level of the posterior end of the inferior turbinate. In the area of ​​the pharyngeal opening of the auditory tube there is an accumulation of lymphoid tissue

- tubal tonsil (tonsilla tubaria).

Under normal conditions, the walls in the membranous-cartilaginous region are adjacent to each other. The tube opens during chewing, yawning and during swallowing movements. The opening of the lumen of the tube occurs with muscle contraction - straining the velum palatine (m. tensor veli palatini) And levator soft palate (m. levator veli palatini). The fibers of these muscles are woven into the thickness of the wall of the membranous-cartilaginous section of the tube.

The mucous membrane of the auditory tube is lined with ciliated epithelium and contains a large number of mucous glands. The movement of the cilia is directed towards the pharyngeal mouth, and this provides a protective function.

Blood supply The tympanic cavity comes from the system of the external and internal carotid arteries. The basin of the external carotid artery includes a. stylomastoidea- branch a. auricularis posterior, a. tympanica anterior - branch a. maxillaris. Branches extend from the internal carotid artery to the anterior parts of the tympanic cavity. Venous drainage carried out mainly in plexus pterygoideus, plexus caroticus, bulbus v. jugularis. Lymphatic drainage from the tympanic cavity goes to the retropharyngeal and deep cervical lymph nodes.

Innervation mucous membrane of the tympanic cavity is due mainly to the tympanic nerve (n. tympanicus), originating from the system n. glossopharyngeus, anastomosing with branches of the facial, trigeminal nerves and sympathetic plexus internal carotid artery.

Mastoid. The posterior part of the middle ear is represented by the mastoid process (processes mastoideus), in which there are numerous air cells connected to the tympanic cavity through antrum and aditus ad antrum in the superior posterior part of the supratympanic space. In newborns, the mastoid process is not developed and is present in the form of a small elevation near the tympanic ring above and behind, containing only one cavity - the antrum. The development of the mastoid process begins in the 2nd year of life and is completed mainly by the end of the 6th - beginning of the 7th year of life.

The mastoid process of an adult resembles a cone, with its apex turned down. Upper limit serves linea temporalis, which is a continuation of the zygomatic process and approximately corresponds to the level of the bottom of the middle cranial fossa. The anterior border of the mastoid process is the posterior wall of the external auditory canal, at the posterosuperior edge of which there is a protrusion -spina suprameatum(ridge of Henle). This protrusion is located slightly below and in front of the projection caves(antrum), located at a depth of approximately 2-2.5 cm from the surface of the bone.

The mastoid cave is a rounded congenital air cell that is constantly present in the mastoid process, regardless of its shape and structure. It is the most reliable anatomical landmark in almost all ear surgeries.

In infants, it is located above the ear canal and rather superficially (at a depth of 2-4 mm), then gradually moves posteriorly and downward. Cave roof (tegmen antri)- a bone plate that separates it from the dura mater of the middle cranial fossa.

The structure of the mastoid process varies depending on the number of air cavities in it, their size and location. The formation of these cavities occurs by replacing bone marrow tissue with ingrown mucoperiosteum. As the bone grows, the number of air cells communicating with the cave increases all the time. According to the nature of pneumatization, they distinguish pneumatic, diploetic and sclerotic types of structure of the mastoid process (Fig. 5.9).

Rice. 5.U. Types of mastoid structure:

a - pneumatic; b - diploetic; c - sclerotic

At pneumatic type of structure, air cells fill almost the entire process and sometimes even extend to the scales of the temporal bone, the zygomatic process, and the pyramid. Usually a zone of smaller cells forms near the cave; towards the periphery they become increasingly larger, often with a large apical cell.

Diploetic(spongy, spongy) type of structure is characterized by a small number of air cells. They are located mainly around the cave and are small cavities bounded by trabeculae.

Sclerotic(compact) type of process structure is a consequence of metabolic disorders or the result of previous general or local inflammatory diseases. In this case, the mastoid process is formed by dense bone tissue with the absence of cells or their minimal number.

Adjacent to the posterior surface of the mastoid process sigmoid sinus (sinus sigmoideus)- venous sinus through which blood flows from the brain to the jugular vein system. Under the bottom of the tympanic cavity, the sigmoid sinus forms an extension - the bulb of the jugular vein. The sinus is a duplicate of the dura mater and is delimited from the cellular system of the mastoid process by a thin but fairly dense bone plate (lamina vitrea). The destructive-inflammatory process in the mastoid process in diseases of the middle ear can cause

lead to the destruction of this plate and the penetration of infection into the venous sinus.

The presentation of the sinus, when it is located close to the posterior wall of the ear canal, or lateroposition (superficial location), pose a risk of injury during operations on

On the inner surface of the apex of the mastoid process there is a deep furrow (incisura mastoidea), where the digastric muscle attaches. Through this groove, pus sometimes breaks out from the cells of the process under the neck muscles.

Blood supply mastoid region is carried out from the external carotid artery system through a. auricularis posterior, venous outflow - into the vein of the same name, which flows into v. jugularis externa. Innervated mastoid area with sensory nerves from the upper cervical plexus: n. auricularis magnus And n. occipitalis minor.

5.1.3. Clinical anatomy of the inner ear

The inner ear, or labyrinth, is located in the thickness of the pyramid of the temporal bone and consists of a bone capsule and a membranous formation included in it, the shape of which follows the structure of the bone labyrinth (Fig. 5.10). There are three sections of the bony labyrinth:

Middle - vestibule (vestibulum);

anterior - cochlea (cochlea);

posterior - system of three semicircular canals (canalis semicircularis).

Laterally, the labyrinth is the medial wall of the tympanic cavity, into which the windows of the vestibule and cochlea face, medially it borders on the posterior cranial fossa, with which it is connected by the internal auditory canal (meatus acusticus internus), vestibule water supply (aquaeductus vestibuli) and snail aqueduct (aquaeductus cochleae).

Snail (cochlea) is a bony spiral canal that has approximately two and a half turns around in humans bone rod (modiolus), from which it extends into the canal bony spiral plate (lamina spiralis ossea). The cochlea in section has the appearance of a flattened cone with a base width of 9 mm and a height of 5 mm, the length of the spiral bone canal is about 32 mm. Bone spiral-

nal plate together with the membranous basilar plate, which is its continuation, and vestibule (Reisner's) membrane (membrana vestibuli) form an independent canal inside the cochlea (ductus cochlearis), which divides the cochlear canal into two spiral corridors - upper and lower. Upper section of the canal - staircase vestibule (scala vestibuli), lower - scala tympani (scala tympani). The staircases are isolated from each other along their entire length, only in the area of ​​the apex of the cochlea they communicate with each other through a hole (helicotrema). The scala vestibule communicates with the vestibule, the scala tympani borders the tympanic cavity through the window of the cochlea and does not communicate with the vestibule. At the base of the spiral plate there is a channel in which the spiral ganglion of the cochlea (gangl. spirale cochleae)- here are the cells of the first bipolar neuron of the auditory tract. The bony labyrinth is filled with perilymph, and the membranous labyrinth located in it is filled with endolymph.

vestibule (vestibulum) - the central part of the labyrinth, phylogenetically the most ancient. This is a small cavity, inside of which there are two pockets: spherical (recessus sphericus) And elliptical (recessus ellipticus). In the first, closer to the cochlea, there is spherical sac (sacculus), in the second, adjacent to the semicircular canals - utricle (utriculus). The anterior part of the vestibule communicates with the cochlea through the scala vestibule, and the posterior part communicates with the semicircular canals.

Semicircular canals (canalis semicircularis). The three semicircular canals are located in three mutually perpendicular planes: lateral or horizontal (canalis semicircularis lateralis) is at an angle of 30° to the horizontal plane; anterior or frontal vertical canal (canalis semicircularis anterior)- in the frontal plane; posterior or sagittal vertical semicircular canal (canalis semicircularis posterior) located in the sagittal plane. Each channel has an extended ampullary and smooth knee, facing the elliptical recess of the vestibule. The smooth bends of the vertical canals - frontal and sagittal - are merged into one common bend. Thus, the semicircular canals are connected to the elliptical recess of the vestibule by five openings. The ampulla of the lateral semicircular canal comes close to aditus ad antrum, forming its medial wall.

Rice. 5.10. Bone labyrinth:

1 - window of the vestibule; 2 - cochlear window; 3 - lateral (horizontal) semicircular canal; 4 - anterior semicircular canal; 5 - posterior semicircular canal; 6 - snail

Membranous labyrinth is a closed system of cavities and canals, basically repeating the shape of the bone labyrinth (Fig. 5.10). The space between the membranous and bony labyrinth is filled with perilymph. This space is very small in the area of ​​the semicircular canals and expands somewhat in the vestibule and cochlea. The membranous labyrinth is suspended within the perilymphatic space by connective tissue cords. The cavities of the membranous labyrinth are filled with endolymph. Perilymph and endolymph represent the humoral system of the ear labyrinth and are functionally closely related. Perilymph in its ionic composition resembles cerebrospinal fluid and blood plasma, endolymph - intracellular fluid. The biochemical difference concerns primarily the content of potassium and sodium ions: in the endolymph there is a lot of potassium and little sodium, in the perilymph the ratio is the opposite. The perilymphatic space communicates with the subarachnoid space through the cochlear aqueduct; the endolymph is located in the closed system of the membranous labyrinth and has no communication with brain fluids.

It is believed that endolymph is produced by the stria vascularis and is reabsorbed in the endolymphatic sac. Excessive production of endolymph by the stria vascularis and

Rice. 5.11. Relationship between the bony and membranous labyrinths: 1 - lateral semicircular canal; 2 - anterior and posterior semicircular canals; 3 - elliptical pouch; 4 - endolymphatic sac; 5 - spherical bag; 6 - snail

disruption of its absorption can lead to increased intralabyrinthine pressure.

From anatomical and functional points of view, two receptor apparatuses are distinguished in the inner ear:

The auditory organ is located in the membranous cochlea (ductus cochlearis);

vestibular, in vestibular sacs (sacculus and utriculus) and in three ampoules of the membranous semicircular canals.

webbed snail, or cochlear duct (ductus cochlearis) located in the cochlea between the scala vestibule and scala tympani (Fig. 5.12). In a cross-section, the cochlear duct has a triangular shape: it is formed by the vestibular, tympanic and outer walls (Fig. 5.13). The upper wall faces the scala vestibule and is formed by a thin wall consisting of two layers of flat epithelial cells vestibular (Reisner's) membrane (membrana vestibularis).

The bottom of the cochlear duct is formed by a basilar membrane, separating it from the scala tympani. The edge of the bony spiral plate is connected through the basilar membrane to the anti-

Rice. 5.12. Frontal section of the cochlea:

1 - staircase vestibule; 2 - cochlear staircase; 3 - cochlear duct; 4 - spiral knot; 5 - cochlear part of the vestibulocochlear nerve

on the opposite wall of the bony cochlea, where the cochlear duct is located spiral ligament (lig. spirale), the upper part of which, rich in blood vessels, is called vascular strip (stria vascularis). The basilar membrane has an extensive network of capillary blood vessels and is a formation consisting of transversely located elastic fibers, the length and thickness of which increases in the direction from the main curl to the apex. On the basilar membrane, located spirally along the entire cochlear duct, lies spiral organ of Corti- peripheral receptor of the auditory analyzer (Fig. 5.14).

Rice. 5.13. Location of the cochlear duct in the basal curl of the cochlea: 1 - scala vestibule; 2 - scala tympani; 3 - cochlear duct

The spiral organ consists of neuroepithelial inner and outer hair cells, supporting and nourishing cells (Deiters, Hensen, Claudius), outer and inner pillar cells forming the arches of Corti. Inward from the inner pillar cells there is a number of inner hair cells (about 3500 of them); Outside the outer pillar cells are about 20,000 outer hair cells. Hair cells synapse with peripheral nerve fibers emanating from the bipolar cells of the spiral ganglion. The supporting cells of the organ of Corti perform supporting and trophic functions. Between the cells of the organ of Corti there are intraepithelial spaces filled with fluid called cortilymph. Cortilymph is quite similar in chemical composition to endolymph, but it also has significant differences.

Above the hair cells of the organ of Corti is located covering membrane (membrana tectoria), which, just like the basic

Rice. 5.14. Spiral organ of Corti:

1 - vestibule (Reisner's) membrane; 2 - hair cells; 3 - spiral knot; 4 - nerve fibers to hair cells; 5 - supporting cells; 6 - cover membrane; 7 - vascular strip

The polar membrane extends from the edge of the bony spiral plate and hangs over the basilar membrane, since its outer edge is free. The covering membrane consists of protofibrils, having a longitudinal and radial direction, the hairs of neuroepithelial outer hair cells are woven into it. When the basilar membrane vibrates, the distance between these membranes also changes, tension and compression of the hairs of neuroepithelial cells occurs, which leads to the conversion of the mechanical energy of vibrations of the stapes and the fluids of the inner ear into the energy of a nerve impulse. In the organ of Corti, only one terminal nerve fiber approaches each sensory hair cell, which does not give branches to neighboring cells, so degeneration of the nerve fiber leads to the death of the corresponding cell.

It should be noted that there is afferent and efferent innervation of the sensory cells of the organ of Corti, which carries out centripetal and centrifugal flow. 95% of afferent (centripetal) innervation falls on the inner hair cells. On the contrary, the main efferent flow is directed to the outer hair cells.

Membranous semicircular canals are located in the bone canals, repeat their configuration, but are smaller in diameter, with the exception of the ampullary sections, which are almost completely

bone ampoules are removed (Fig. 5.15 a). The membranous canals are suspended from the endosteum of the bone walls by connective tissue cords in which the feeding vessels pass. The inner surface of the canal is lined with endothelium; in the ampoules of each of the semicircular canals there are ampullary receptors, representing a small circular protrusion - crest (crista ampullaris), on which supporting and sensitive receptor cells are located, which are peripheral receptors of the vestibular nerve. Among the receptor hair cells, thinner and shorter immobile hairs are distinguished - stereocilia, the number of which reaches 50-100 on each sensitive cell, and one long and thick mobile hair - kinocilium, located on the periphery of the apical surface of the cell. The processes of excitation of the vestibular apparatus are associated with the hair apparatus of receptor cells. The movement of endolymph during angular acceleration towards the ampulla or smooth knee of the semicircular canal leads to irritation of neuroepithelial cells. It is assumed, in particular, that a change in the distance between the kinocilium and stereocilia leads to hypo or hyperpolarization, which results in an increase or decrease in the flow of impulses from the receptor cell.

In the vestibule of the labyrinth there are two membranous sacs - elliptical and spherical (utriculus et sacculus), in the cavity of which are located otolith receptors. IN utriculus semicircular canals open sacculus connects the rheunia duct with the cochlear duct. According to the sacs, the receptors are called macula utriculi And macula sacculi and represent small elevations on the inner surface of both sacs, lined with neuroepithelium (Fig. 5.15 b). This receptor apparatus also consists of supporting and sensory cells. The hairs of sensitive cells, intertwining their ends, form a network, which is immersed in a jelly-like mass containing a large number of calcium carbonate crystals in the shape of octahedrons. The hairs of sensitive cells, together with otoliths and a jelly-like mass, form otolith membrane. Among the hairs of sensory cells, as well as in the ampullary receptors, kinocilia and stereocilia are distinguished. The pressure of otoliths on the hairs of sensitive cells, as well as the displacement of hairs during linear accelerations, is the moment of transformation of mechanical energy into electrical energy.

Rice. 5.15. Scheme of vestibular receptors:

a - ampullary receptor: 1 - lumen of the ampulla of the semicircular duct; 2 - ampullary comb; 3 - lumen of the elliptical sac; 4 - statoconia membrane; 5 - connective tissue cords; 6 - kinocilium; b - statoconia receptor: 1 - statoconia membrane; 2 - receptor cells

ical in neuroepithelial hair cells. The elliptical and spherical sacs are connected to each other by means of a thin tubule - ductus utriculosaccularis, which has a branch

nie - endolymphatic duct (ductus endolymphaticus). Passing through the aqueduct of the vestibule, the endolymphatic duct emerges onto the posterior surface of the pyramid and there blindly ends with the endolymphatic sac (saccus endolymphaticus), representing an expansion formed by duplication of the dura mater.

Thus, the vestibular sensory cells are located in five receptor areas: one in each ampulla of the three semicircular canals and one in the two sacs of the vestibule of each ear. In the nerve receptors of the vestibule and semicircular canals, not one (as in the cochlea), but several nerve fibers approach each sensitive cell, so the death of one of these fibers does not entail the death of the cell.

Blood supply to the inner ear carried out through the labyrinthine artery (a. labyrinthi), which is a branch of the basilar artery (a. basilaris) or its branches from the anterior inferior cerebellar artery (Fig. 5.16). In the internal auditory canal, the labyrinthine artery is divided into three branches: vestibular (a. vestibularis), vestibulocochlear (a. vestibulocochlearis) and cochlear (a. cochlearis).

Rice.5 .16. Blood supply of the labyrinth:

1 - vertebral artery; 2 - basilar artery; 3 - anterior inferior cerebellar artery; 4 - artery of the labyrinth

Features of the blood supply to the labyrinth are that the branches of the labyrinthine artery do not have anastomoses with the vascular system of the middle ear, the Reissner membrane is devoid of capillaries, and in the area of ​​the ampullary and otolith receptors the subepithelial capillary network is in direct contact with neuroepithelial cells. Blood vessels do not approach the neuroepithelial hair cells of the spiral organ; their nutrition is carried out indirectly through the trophic cells adjacent to them.

Venous drainage from internal ear goes along three routes: the veins of the cochlear aqueduct, the veins of the vestibular aqueduct and the veins of the internal auditory canal.

INNERVATION OF THE INNER EAR

Hearing analyzer(Fig. 5.17). Hair cells of the organ of Corti synapse with peripheral processes of bipolar cells spiral ganglion (ganglion spirale), located at the base of the spiral plate of the cochlea. The central processes of the bipolar neurons of the spiral ganglion are fibers of the auditory (cochlear) portion of the VIII nerve (n. cochleovestibularis), which passes through the internal auditory canal and enters the pons in the region of the cerebellopontine angle. At the bottom of the fourth ventricle, the VIII nerve divides into two roots: the superior vestibular and inferior cochlear.

The fibers of the cochlear root end in the lateral corner of the rhomboid fossa on the cells of the ventral nucleus (nucl. ventralis) and dorsal cochlear nucleus (nucl. dorsalis). Thus, the spiral ganglion cells, together with the peripheral processes going to the neuroepithelial hair cells of the organ of Corti, and the central processes ending in the pontine nuclei, constitute I neuron of the auditory analyzer. At the level of the cochlear nuclei there are a number of nuclear formations that take part in the formation of further pathways for auditory stimulation: the nucleus of the trapezoid body, the superior olive, the nucleus of the lateral lemniscus. From the ventral and dorsal nuclei begins II neuron of the auditory analyzer. A minority of the fibers of this neuron go along the side of the same name, and the majority in the form striae acusticae cross and pass to the opposite side of the bridge, ending in the olive and trapezoid body. Fibers III neuron as part of the lateral loop they go to the nuclei of the quadrigeminal and medial

Rice. 5.17. Diagram of the pathways of the auditory analyzer: 1 - cortex of the temporal lobe of the brain; 2 - medial geniculate body; 3 - quadrigeminal tubercles; 4 - lateral loop; 5 - cochlear nuclei; 6 - upper olive cores; 7 - spiral knot; 8 - organ of Corti

th geniculate body, where the fibers come from IV neuron after the second partial decussion, they are sent to the temporal lobe of the brain and end in the cortical part of the auditory analyzer, located mainly in Heschl’s transverse temporal gyri.

Conduction of impulses from cochlear receptors on both sides brain stem explains the fact that one-sided

Her hearing impairment occurs only in the case of damage to the middle and inner ear, as well as the cochleovestibular nerve and its nuclei in the bridge. With unilateral damage to the lateral lemniscus, subcortical and cortical auditory centers, impulses from both cochlear receptors are conducted along the unaffected side to one of the hemispheres and there may be no hearing impairment.

The auditory system provides the perception of sound vibrations, conduction of nerve impulses to the auditory nerve centers, and analysis of the information received.

Vestibular analyzer. Receptor cells of the vestibular analyzer contact the endings of the peripheral processes of bipolar neurons of the vestibular ganglion (gangl. vestibulare), located in the internal auditory canal. The central processes of these neurons form the vestibular portion of the vestibulocochlear (VIII) nerve, which passes through the internal auditory canal, exits into the posterior cranial fossa and, in the region of the cerebellopontine angle, is embedded in the substance of the brain. In the vestibular nuclei of the medulla oblongata, in the floor of the fourth ventricle, it ends I neuron. The vestibular nuclear complex includes four nuclei: lateral, medial, superior and descending. From each nucleus the second neuron comes with a predominant decussation.

The high adaptive capabilities of the vestibular analyzer are due to the presence of many associative pathways of the nuclear vestibular complex(Fig. 5.18). From the standpoint of clinical anatomy, it is important to note five main connections of the vestibular nuclei with various formations of the central and peripheral nervous system.

*Vestibulospinal connections. Starting from the lateral nuclei of the medulla oblongata, as part of the vestibulospinal tract, they pass through the anterior horns of the spinal cord, providing communication between vestibular receptors and muscular system. *Vestibulo-oculomotor connections are made through the system of the posterior longitudinal fasciculus: from the medial and descending nuclei of the medulla oblongata there is a crossed path, and from the superior nucleus there is an uncrossed path to the oculomotor nuclei. *Vestibulo-vegetative connections are made from the medial nucleus to the nuclei of the vagus nerve, reticular pharmacy, and diencephalic region.

Rice. 5.18. Scheme of associative connections of the vestibular analyzer: 1 - labyrinth; 2 - spiral ganglion; 3 - cerebellum; 4 - cerebral cortex; 5 - nuclei of oculomotor nerves; 6 - reticular formation; 7 - vestibular nuclei in the medulla oblongata; 8 - spinal cord

*Vestibulocerebellar the pathways pass in the internal part of the inferior cerebellar peduncle and connect the vestibular nuclei with the cerebellar nuclei.

*Vestibulocortical connections are provided by a system of fibers running from all four nuclei to the visual thalamus. Interrupting in the latter, these fibers then go to the temporal lobe of the brain, where the vestibular analyzer has a diffuse representation. The cortex and cerebellum perform a regulatory function in relation to the vestibular analyzer.

Through these connections, various sensory, autonomic and somatic vestibular reactions are realized.

Blood supply to the inner ear carried out solely through the deep auricular artery (a. auricularis profunda). In cases of circulatory disturbance in the system of this artery, one cannot count on restoring blood supply in the inner ear at the expense of some other artery, since the artery of the inner ear has almost no anastomoses with other vessels. Blood circulation in the inner ear is regulated by the sympathetic nervous system. The artery of the inner ear provides blood supply to:

1) the organ of Corti, in which the mechanical energy of acoustic vibrations is transformed into biochemical energy, resulting in the active electrical potential of the cochlea; with a decrease in the amount of oxygen delivered by the blood to sensitive cells, the intensity of this process sharply decreases; long periods of oxygen deficiency lead to degenerative changes in the sensory cells of the organ of Corti;
2) stria vascularis of the cochlea, the cells of which produce lymph (lympha), which is the liquid medium of the membranous labyrinth, through which the mechanical energy of acoustic vibrations in the inner ear is transmitted.

Endolymph(endolympha) fills the lumen of the membranous labyrinth, and the regulation of endolymph pressure is carried out due to its outflow through the vestibular aqueduct (aquaeductus vestibuli) into the endolymphatic sac (saccus endolymphaticus), where fluid absorption occurs. Increased permeability of the walls of blood vessels stria vascularis and congestion large quantity fluid inside the labyrinth leads to increased pressure if absorption in the endolymphatic sac is insufficient.

Increased amount of endolymph in the membranous labyrinth, and therefore the increased pressure inside it, can also be equalized due to the leakage of fluid into the perilymph surrounding the membranous labyrinth, from where excess fluid is directed through the cochlear aqueduct into the subarachnoid space of the brain. The function of the system that regulates the pressure of the endolymph in the membranous labyrinth may be insufficient, resulting in certain types of disorders. Fluid accumulated inside the membranous labyrinth prevents normal conductivity acoustic irritations to the organ of Corti and, in addition, has an irritating effect on the organ of balance. Conduction deafness occurs. Excessive fluid in the membranous labyrinth for a long time mechanically, due to constant high blood pressure, damages the cells of the organ of Corti, resulting in a violation of sound-radiation.

Due to blood supply to the inner ear is carried out almost exclusively only through the deep auricular artery and its branches; compensation for the disorders described above is carried out at an extremely slow pace.

Etiology of these diseases is very diverse, but their symptoms are very similar: 1) deafness, 2) tinnitus, 3) balance disorders (dizziness, falling). If a circulatory disorder affects only the function of the hearing organ, then conduction deafness or perceptual deafness occurs, or, finally, deafness mixed type, as well as tinnitus; if the blood supply to the balance organ deteriorates, then dizziness and balance disorders are noted.

In otolaryngological practice Doctors most often encounter such patients who simultaneously have damage to both one and the other organ of the inner ear. Balance disorders can be paroxysmal, and hearing loss and tinnitus often appear later. long time after the first symptoms of imbalance.

In some cases, all these symptoms: tinnitus, decreased hearing, severe dizziness, inability to maintain body balance, occur simultaneously and are paroxysmal in nature. In some patients, the symptoms of the disease are very variable and inconsistent, in others they always have the same character. In case of imbalance, the disease has a paroxysmal character; in case of hearing impairment, a gradual increase in deafness is usually observed.

To those described above symptoms dysfunction of the vestibular apparatus is usually associated with mental disorders; feeling of fear, nervous excitement. Labyrinth diseases of different manifestations due to circulatory disorders, depending on the nature of the lesion, can be divided into three types: labyrinthine hydrops (hydrops labyrinthicus), intralabyrinthine hemorrhage (haemorrhagia labyrinthi), vascular spasm (angiospasmus).

I. Dropsy of the labyrinth is the most common cause of the symptoms described above, grouped under common name. Hydropsy of the labyrinth occurs due to an increase in the permeability of the walls of blood vessels and is accompanied by hearing impairment such as conduction deafness due to an increase in the mass (m) through which acoustic vibrations pass, an increase in friction between particles of the eidolymph (g) due to changes in its viscosity and chemical composition; as well as a decrease in mobility (s), caused by fluid retention in a confined space.

Etiological aspects of dropsy labyrinth can be the following:
1) allergic reactions to exo- and endogenous allergens; endogenous, bacterial, allergens are as often the cause of Meniere's syndrome as exogenous allergens,
2) excretory dysfunction endocrine glands,
3) vasomotor disorders,
4) various types of disorders of the regulatory function of the sympathetic nervous system.

II. Disease, caused by intralabyrinthine hemorrhage, was first described by Meniere, and is still called Meniere's disease. The causes of hemorrhage into the labyrinth may be the following: 1) hypertonic disease, 2) hormonal disorders, especially in women, 3) sclerosis of blood vessels, 4) blood diseases characterized by a tendency to hemorrhages, 5) cranial injuries.

III. Vascular spasm(angiospasmus) is associated with changes in the regulatory function of the autonomic nervous system.

In contrast to the first two types lesions, which, as a rule, are unilateral, spasm of blood vessels is observed simultaneously on both sides. This kind of labyrinth disease begins sudden loss hearing and tinnitus. If vascular spasm is not resolved for a long time, then congestion develops in the venous system, the permeability of the walls of blood vessels increases and swelling of the labyrinth occurs. In this case, there is deafness of perception, especially in the initial stages, which distinguishes this disease from the lesions of the inner ear described in points I and P. Balance disorders in this case are less typical than with Meniere's syndrome.

This rather broad group includes diseases varying in severity and course. which are united only by a common etiology. However, this commonality is predominantly formal in nature, since changes in the vessels are not the same. This includes processes ranging from mild hemodynamic changes to severe forms of cerebral atherosclerosis, hemorrhages, thrombosis, embolism, and malignant hypertension.

One of the features pathogenesis of hearing diseases is the possible impact of vascular pathology on the cochlear and vestibular analyzers along their entire length - from the periphery to the center. As is known, blood supply is provided by two interconnected arterial systems: the inner ear and the 1st neuron are supplied from the vertebral artery; conductors and centers - from the internal carotid artery.

Dynamic disturbances in each of these conditions may lead to a disorder of auditory or vestibular function. Damage to nerve conductors in the brain and centers is clinically affected by symptoms of cortical hearing loss, increased fatigue of the hearing organ, and the appearance of central vestibular symptoms. More frequent and important type vascular lesion ear is peripheral, i.e., damage to the cochlea and semicircular canals, which is apparently associated with the conditions of blood circulation and blood supply to the inner ear and the sensitivity of the endings of the vestibular and cochlear nerves located in it.

When narrowing internal auditory artery the nutrition of the organ of Corti, nerve fibers and ganglion cells is disrupted; At the same time, changes occur in the endolymph due to disruption of its production by striae vaseularis cells. Increased vascular permeability associated with diseases of the vascular system can lead to the formation of exudate.

The basis of vascular disorders often lies a slow and gradually developing degenerative-atrophic process in the cells of the organ of Corti, gradually spreading to ganglion cells and nerve fibers. The same process occurs in the vestibular apparatus. In the relatively rare (in non-syphilitic arteriosclerosis) apoplectiform type of the disease, changes may occur in various parts of the inner ear, depending on the location of the blood clot or the extent and location of the hemorrhage.

Out of 100 patients. of those who applied for noise and hearing loss and did not present other complaints, Stein found cardiovascular changes in almost half, including 24 arteriosclerosis. In 16 of these patients, damage to the sound-receiving apparatus was established. Among these patients there were no persons over 56 years of age, and half of them were aged 38-50 years.

Among those complaining about noise in ears. many suffer from organic or functional disorders blood circulation (according to Stein, in 64.4%; including 42.2% had organic diseases of the heart and blood vessels). The noise in some cases is either a consequence of irritation of the nervous tissue in the cochlea, or a slowdown and obstruction of blood flow in the vessels located close to the ear.

What causes pulsation in the ear?

The feeling of pulsation in the ears is a fairly common symptom that accompanies many diseases and conditions. But regardless of the reasons that caused this symptom, it is a very unpleasant and uncomfortable sensation that can in itself greatly complicate a person’s life. In addition to the fact that pulsation significantly reduces hearing acuity, it can provoke extreme irritability, insomnia, loss of appetite and other disorders that - sooner or later - become the cause of new health problems.

Causes of pulsation in the ears

All the reasons why this symptom develops can be divided into four conditional categories:

• cardiovascular disorders;
• traumatic conditions;
• tumor diseases.

Cardiovascular disorders

Any of the following diseases of the heart and blood vessels can provoke a feeling of pulsation:

• hypertension and hypotension disrupt vascular tone, as a result of which the blood pressure in the inner ear insufficiently or excessively fills the capillaries and leads to the sound of “friction” of blood through the vessels - pulsating noise;
• atherosclerosis leads to a decrease in the elasticity of the walls of blood vessels, due to which the vessels are unable to contract in the same rhythm as the heartbeat. The pulsation, which stands out from the general rhythm, becomes audible;
• narrowing of the carotid artery, jugular vein, arteriovenous shunts and other defects in vascular anatomy create a kind of turbulent flow of blood that hits the walls of blood vessels, and in the immediate vicinity of the cells of the inner ear these “beats” of blood are perceived as pulsation.

Diseases of the middle and inner ear

Acoustic signals are processed and transmitted to the brain through a highly complex system that consists of many elements. Certain disorders in the structures of the middle and inner ear can not only distort sound waves or reduce their perception by auditory cells, but also cause the sensation of pulsation.

The following conditions cause fluid drainage problems and can create an “echo effect” in which internal noises, including blood pulsations, are amplified:

• blockage of the ear canal with wax;
• inflammation of the middle ear (otitis) with impaired fluid outflow or formation of pus;
• inflammation in the tympanic cavity and eustachian tube (tubo-otitis);

As a result of inflammation of the bone structure of the inner ear (labyrinth), disruption of the functions of special auditory cells, which are responsible for the transformation of acoustic signals into electrical signals, can occur. Signal distortion can cause the sensation of noise and ringing in the ears, as well as pulsation.

Traumatic conditions

Injuries to any part of the ear, as well as traumatic brain injuries, can cause, among others, the symptom of pulsation in the ears. This is due to a temporary disruption of blood circulation in the injured area and swelling developing in the damaged area.

Tumor diseases

Neoplasms in the auditory nerve, brain, spinal cord, in the neck area can cause persistent pulsation in the ears. As the tumor grows, it affects nearby vessels and if among them there is a large vein or artery supplying blood to the inner ear and/or brain, a pulsation symptom develops.

Other reasons

Pregnancy, as well as age-related changes in the structures of the inner ear and blood vessels, are also a common cause of pulsation in the ears.

In the first case, hormones are responsible for the feeling of pulsation, the changed level of which causes disturbances. water-salt metabolism. As a result, swelling of the mucous membranes develops, including the mucosa of the middle and inner ear.

Age-related changes in blood vessels (atherosclerosis, sclerosis, etc.), as well as a gradual decrease in the functionality of auditory cells, lead to distortion of acoustic signals coming from the outside, and at the same time, the audibility of blood friction against the walls of blood vessels increases.

Another risk factor remains medications. For example, unjustified or uncontrolled use of gentamicin or aspirin can cause damage to the cells of the inner ear and cause various hearing disorders.

Characteristics

Depending on the reason for the sensation of pulsation in the ears, this condition is accompanied by the following symptoms:

Cardiovascular disorders

The pulsation, caused by diseases of the heart and blood vessels, increases in the lying position, when the ear is pressed to the pillow. When bending forward, lifting heavy objects, moving up the stairs, the pulsation may be accompanied by a feeling of heaviness in the head and “collar syndrome” - a feeling of tightness in the neck, as if a tight tie is on it.

With atherosclerosis, the pulse heard in the ears does not coincide in rhythm with the pulse heard on the wrist. In other cardiovascular disorders, pulsation in the ears usually coincides with the heart rhythm.

Diseases of the middle and inner ear

treatment of the disease that caused the pulsation is a kind of prevention of serious psychological health disorders

If any hearing disease is responsible for the feeling of blood pulsating in the ears, the pulsation may be accompanied by:

• sensation of fluid transfusion in the ear;
• feeling of pressure in the ears;
• with a unilateral disease (when one ear is affected by inflammation), pulsation is heard only on the affected side;
• decreased hearing acuity.

Traumatic conditions

Pulsation, caused by damage to any structure of the ear or traumatic brain injury, develops within several hours after the injury and the intensity of the pulsation of blood in the ears will increase as swelling or post-traumatic inflammation increases. As a rule, pulsation becomes more noticeable with head movements, bending, and is accompanied by headaches of various types - dull, pressing, paroxysmal, etc.

Tumor diseases

Pulsation in tumor diseases most often occurs on one side: the tumor compresses blood vessels And nerve endings, providing the functions of only one ear. Much less commonly, pulsation can be caused by a tumor cervical region spine, in this case the sensation of pulsation develops in both ears.

Treatment

Since pulsation in the ears is not an independent disease, but only a symptom, the disease that caused this unpleasant sensation is subject to treatment.

Important: Neurotic and mental disorders are one of the most common complications that develop with prolonged pulsation in the ears. Among such neurotic conditions are increased aggression, insomnia, apathy, depression, and anorexia. Therefore, treatment of the disease that caused the pulsation is a kind of prevention of serious psychological health disorders.

How to deal with tinnitus

Tinnitus is a common complaint among patients, especially hypertensive patients and the elderly. The reasons may vary. Every person strives to think clearly, and the feeling of constant noise or ringing leads to severe neurasthenia and mental inferiority.

Description of the symptom

In scientific terms, the feeling of noise or ringing in the ears can be characterized as a subjective sign or extraneous sound, audible only by the patient. Noise is expressed in the form of rustling, creaking, humming, whistling, hissing, buzzing. Disturbs in one ear or both at once.

Patients note the paroxysmal nature of such sensations. There are long periods. More often, localization is associated with the entire head.

A person understands that in reality sounds do not exist, no one but him hears them. He perceives his sensations as torture and suffers from insomnia.

Sleep disturbances and stress reactions serve as a reason for exacerbation of various chronic diseases. Therefore, it is important to identify the possible cause and choose the right treatment.

Let's consider possible diseases accompanied by tinnitus.

Ear diseases

Here we should mention a variety of reasons from wax plugs and foreign bodies in the ear canal, to complex diseases of the inner ear.

Ear plugs are formed as a result of impaired cleaning of the ear canals. The particles dry out, become dense and provide auditory sensations when moving.

Ingress of water while swimming causes ringing in one ear, which can be easily eliminated by inserting an absorbent tampon.

Small objects that enter the ear canal (such as insects) cause excruciating pain and ringing. Specialist intervention is required to remove them.

Inflammation of the middle ear, chronic sinusitis cause impairment of auditory perception, swelling of the eardrum. The noise usually appears only in the inflamed ear.

Meniere's disease is a disorder of the inner ear caused by fluid accumulation and pressure on the auditory and vestibular structures. In addition to tinnitus, various degrees of deafness and dizziness with nausea, vomiting, and unsteady gait occur. Pallor and increased sweating of the skin, fluctuations in blood pressure are typical.

Otosclerosis

Disease of sclerosis of the human auditory apparatus. Occurs as a result of frequent inflammation of the middle ear. It is characterized in the initial stage by impaired sound sensations and gradual hearing loss.

Damage to cerebral vessels

The most common change - vascular atherosclerosis - affects and hardens the arteries of the brain. This process is especially active in hypertension. The two diseases contribute to each other.

Waves of heartbeats pass through the rigid frame of blood vessels without softening, so they are unusually felt like noise. Simultaneous dizziness is associated with a malnutrition of the brain centers that control vestibular functions.

A similar mechanism of tinnitus occurs with impaired vascular tone and vegetative-vascular dystonia in young people.

Migraine

Migraine is also associated with changes in vascular tone due to various nervous and endocrine lesions. Headaches and one-sided, paroxysmal noise are considered typical. Accompanied by warning symptoms, photophobia, and odor intolerance.

Neurosis

Neurosis-like states often accompany hard work, scandals, fright, and fear. The person becomes irritable, sleep disturbances, headaches, weakness, dizziness and ringing in the ears appear.

All manifestations go away after a good rest and taking sedatives.

Changes in the bone tissue of the spine

Feeding arteries run along the vertebrae. Osteochondrosis of the cervical spine. disc protrusion can cause oxygen deficiency in the brain, squeezing it with bone outgrowths.

Symptoms occur simultaneously with headaches. dizziness, noise all over the head. They are associated with uncomfortable body position during sleep. A provocation of an attack occurs when the head is tilted back.

Skull injuries

Skull injuries in the acute period or during recovery are characterized by nausea, headaches, hearing loss, and tinnitus. They are associated with direct irritation of the brain nuclei. Nerve cells can independently cause sound disorders.

Tumor

Malignant and benign tumors of the auditory nerve (neurinomas) are accompanied by pain in the ear, hearing loss, a sensation of “pins and needles” on the scalp, and various manifestations of extraneous noise.

Occupational poisoning, side effects of drugs

The occurrence of tinnitus is promoted by the toxic effects of toxic substances and chemicals(drugs) on auditory nerve cells. This leads to:

• poisoning with arsenic compounds, mercury, lead;
• long-term use of aspirin medications, antibiotics, aminophylline, prednisolone, quinine.

Toxic effects revealed large doses alcohol and caffeine.

Barotrauma

The connection between tinnitus and a sharp change in atmospheric pressure is known to people involved in underwater sports, pilots, and parachutists. The dependence of the “sound accompaniment” during takeoff and landing is felt by airline passengers.

In this case, the thin eardrum reacts.

To choose a treatment for such a common symptom, you need the help of several specialists: a therapist, a neurologist, an otolaryngologist. A cardiological examination may be required. The real reason may be quite serious and cause disappointing consequences.

External ear, auris externa, includes the pinna and external auditory canal, which form a funnel to capture sounds and direct the sound wave to the eardrum. Auricle,auricula, It has elastic cartilage, cartilago auri​culae, covered with skin tightly adjacent to the cartilage. There is no cartilage in the lower part of the auricle; instead there is a skin fold with adipose tissue inside - lobule of the auricle(lobe), lobulus auriculae. The free edge of the shell is wrapped, forming for​turn, helix, which in the front part of the concha above the external auditory canal ends in the form of a helical stalk, crus helicis. On the inner side of the helix, in its posterior-superior part, there is not always a clearly defined protrusion - ear tubercle, tuberculum auriculae. On the inside of the shell, parallel to the helix, there is an elevation - antihelix, antihelix. In front of the ear canal there is a protrusion - tragus, tragus. Opposite it, in the lower part of the antihelix, is visible antitragus, antitragus. Between the tragus in front and bottom of the antihelix there is a depression at the back - shell cavity, cavitas conchae, continuing into the external auditory canal.

External auditory canal,meatus acusticus externus, open from the outside, ends blindly in the depths, separated from the cavity of the middle ear by the eardrum. The cartilaginous external auditory canal, which is a continuation of the auricle, has the appearance of a groove, open upward, belongs to the bony auditory canal, the temporal bone. The auditory canal is S-shaped curved in the horizontal plane. The ear canal is lined with skin, which, thinning, continues onto the eardrum. The skin covering the cartilaginous part of the ear canal contains a lot of sebaceous glands, producing earwax.

Eardrum, rnembrana tympani-a thin translucent oval plate separates the external auditory canal from the tympanic cavity (middle ear). The tympanic membrane is fixed at the end of the auditory canal in the groove of the tympanic part of the temporal bone. The large lower part of the membrane is tense part, pars tensa, and the upper one, adjacent to the scaly part of the temporal bone, was called loose part, pars flaccida. In the center the membrane has a depression - navel, umbo membranee tympani. The eardrum is made of fibrous tissue.

Blood supply: branches from the external carotid artery system approach the external ear: the anterior auricular branches - from the superficial temporal artery, the auricular branch - from the occipital artery and the posterior auricular artery. In the wall of the external auditory canal, the deep auricular artery branches from the maxillary artery. The same artery is involved in the blood supply to the eardrum. Deoxygenated blood from the external ear it flows through the veins of the same name into the mandibular vein and into the external jugular vein.

Innervation: Greater auricular, vagus and auriculotemporal nerves. The tympanic membrane is approached by branches from the auriculotemporal and vagus nerves, as well as from the tympanic plexus of the cavity of the same name. The tympanic plexus is formed by branches of the tympanic nerve (a branch of the glossopharyngeal nerve).

Middle ear, auris media, includes the air-filled tympanic cavity and the auditory (Eustachian) tube. The middle ear cavity communicates with the mastoid cave and through it with the mastoid cells located in the thickness of the mastoid process.

tympanic cavity,cavitas tympani, located in the thickness of the pyramid of the temporal bone, between the external auditory canal laterally and the bony labyrinth of the inner ear medially. There are 6 walls in the tympanic cavity:

1. Upper tegmental wall, paries tegmentalis

2. Bottom jugular wall, paries jugularis

3. Medial labyrinth wall, paries labyrinthicus,

4. Rear mastoid wall, paries mastoideus

5. Front carotid wall, paries caroticus

6. Lateral membranous wall paries membranaceus

In the tympanic cavity there are three auditory ossicles covered with mucous membrane, as well as ligaments and muscles.

auditory ossicles, ossicula auditus , form a chain that continues from the eardrum to the end of the vestibule, which opens into the inner ear. In accordance with their shape, the bones received names: hammer, anvil, stirrup. Hammer, malleus, has a rounded shape head, which turns into a long one hammer handle, with two processes: lateral and anterior. Anvil, incus consists of a body, with an articular fossa for articulation with the head of the malleus and two legs: one short leg, another - long. Stirrup, stages, has a head, two legs - front and back, crus anterius et crus posterius, connected by base of the stirrup, basis stapedis, inserted into the window of the vestibule. Vibrations of the eardrum, resulting from the impact of a sound wave on it, are transmitted to the window of the vestibule. Two muscles attached to the auditory ossicles regulate the movements of the ossicles and protect them from excessive vibrations during strong sounds. Muscle that tightens the tympanic membrane, m. tensor tympani pulling up the handle of the hammer, strains the eardrum. Stapedius muscle, m. Stapedius, p When it contracts, the pressure of the base of the stapes inserted into the window of the vestibule is weakened.

Auditory (Eustachian) tube,tuba auditiva, serves to bring air from the pharynx into the tympanic cavity and maintain pressure in the cavity equal to the external one, which is important for the normal operation of the sound-conducting apparatus. The auditory tube consists of bone And cartilaginous part. The upper bony part of the tube is located in the hemicanal of the same name of the muscular-tubal canal of the temporal bone and opens on the anterior wall of the tympanic cavity tympanic opening of the auditory tube, ostium tympdnicum tubae auditivae. The lower cartilaginous part is formed by the medial and lateral cartilaginous plates and the membranous plate connecting them

The tensor muscle and the levator palatine muscle originate from the cartilaginous part of the auditory tube. When they contract, the cartilage of the tube and its membranous plate, lamina membranacea, are retracted, the pipe channel expands and air from the pharynx enters the tympanic cavity.

Blood supply: the walls of the auditory tube are supplied with blood by the anterior tympanic artery and the pharyngeal branches of the ascending pharyngeal artery, the petrous branch - from the middle meningeal artery. The artery of the pterygoid canal (a branch of the maxillary artery) gives branches to the auditory tube. The veins drain into the pharyngeal venous plexus, into the meningeal veins (tributaries of the internal jugular vein) and the mandibular vein.

Innervation: in the tympanic cavity - the tympanic plexus, formed by the branches of the tympanic nerve (a branch of the glossopharyngeal nerve). The branches of the pharyngeal plexus are the auditory tube.

Innervation of the auricle unique (Fig. 2, 3). Despite the fact that the auricle is devoid of any specialized functions, it contains afferent nerves of somatic and visceral origin.

The first are represented by the branches of two large nerves - the trigeminal ( n. trigeminus) and cervical plexus ( plexus cervicalis), the second - by the branches of the vagus nerve ( n. vagus), glossopharyngeal nerve ( n. glossopharyngeus) and facial nerve ( n. facialis).

Trigeminal nerve system. Auriculotemporal nerve ( n. auriculotemporalis), the largest, branch of the mandibular nerve - the third branch of the trigeminal nerve at the level of the ear gives nerves to the external auditory canal ( nn. meatus acustici externi), which in the form of two terminal branches penetrate the wall of the external auditory canal, innervate the beginning of the external auditory canal, the concha shuttle and the root of the helix.

Anterior auricular nerves ( nn. auricularis anteriores) are the main nerves of the auricle belonging to the trigeminal system. Their innervation zone: tragus, part of the helix, triangular fossa, antihelix, part of the scaphoid, upper half of the auricle lobule (earlobe). The boundaries of the innervation of the auricle by the trigeminal nerve are shown in Fig. 4.

Cervical plexus nerve system. Greater auricular nerve ( n. auricularis magnus) starts from the third and less often the fourth cervical nerves(C 3 -C 4). At the lower pole of the auricle it is divided into anterior and posterior branches. Anterior branch ( r. anterior) innervates the inner surface of the auricle, then, passing through it, exits to outer surface and innervates most of the earlobe, part of the helix, the scaphoid, the helix groove, the antihelix, the triangular fossa, and the edges of the concha cavity. Thus, the bottom of the concha cavity remains outside the sphere of innervation of the anterior branch.

Posterior branch ( r. posterior) branches mainly in the skin of the inner surface of the ear, partially passes to the outer surface and innervates part of the helix, antihelix and triangular fossa.

Lesser occipital nerve ( n. occipitalis minor), originating from the second and third nerves of the cervical plexus (C 2 -C 3), upper branch (r. superior) innervates the upper pole of the inner surface of the ear, part of the helix and the triangular fossa.

Lower branch ( r. inferior) also innervates part of the inner surface of the ear and, moving along the helix to the outer surface, innervates part of the helix and the rook.

It is important to note that the lesser occipital nerve has anastomoses with the greater auricular or facial nerves. In addition, using connecting branches ( rr. communicantes) the nerves of the cervical plexus connect to the cervical sympathetic ganglia ( ganglion sympaticus). This circumstance is extremely valuable in that the effects on acupuncture points located in the zone of innervation of the cervical nerves can be transmitted to the sympathetic ganglia and then spread throughout the entire sympathetic chain.

The boundaries of the innervation of the auricle by the nerves of the cervical plexus are shown in Fig. 5.

Facial nerve system. According to the data of V.P. Vorobyov, the auriculotemporal nerve (trigeminal nerve system) at the level of the ear is connected to the branches of the intermediate nerve of Wriesberg (facial nerve system) by anastomatic branches ( rr. anastomotici cum n. faciale), which innervate middle part(projection of the concha cavity) of the inner surface of the ear, the entrance to the posterior wall of the external auditory canal, the tragus and pretragus region, the concha cavity, the triangular fossa, the antihelix, most of the auricle lobule (earlobe). The boundaries of the innervation of the auricle by the facial nerve are shown in Fig. 6.

The system of the vagus and glossopharyngeal nerves. At the level of the jugular foramen of the skull, a separate auricular branch departs from the trunk of the vagus nerve ( r. auricularis n. vagi), which, together with the branch of the glossopharyngeal nerve that immediately joined ( r. nerve glossopharyngeus) is directed to the auricle along the jugular vein, through the thickness of the pyramid of the temporal bone.

After leaving the bony canal, these nerves are divided into two branches, which innervate the inner surface of the ear, the subtragal region, the trilateral fossa, and the earlobe. The boundaries of innervation of the auricle by the vagus and glossopharyngeal nerves are shown in Fig. 7 and 8.