The anterior wall of the tympanic cavity is called. Clinical anatomy of the middle ear: walls of the tympanic cavity

Tympanic cavity - the space enclosed between the eardrum and the labyrinth. The shape of the tympanic cavity resembles an irregular tetrahedral prism, with the largest upper-lower dimensions and the smallest between the outer and inner walls. There are six walls in the tympanic cavity: outer and inner; top and bottom; front and back.

Outer (lateral) wall It is represented by the tympanic membrane, which separates the tympanic cavity from the external auditory canal. Up from the tympanic membrane, the plate of the upper wall of the external auditory canal is involved in the formation of the lateral wall, to the lower edge of which (incisura Rivini) the eardrum is attached.

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

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

Medial (internal) The wall of the tympanic cavity separates the middle and inner ear. IN central department this wall has a protrusion - a cape, 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 . The tympanic (or Jacobson) nerve participates in the formation of the tympanic plexus , nn. trigeminus, facialis, as well as sympathetic fibers from plexus caroticus internus.

Behind and above the cape is vestibule window niche, shaped like an oval, elongated in the anteroposterior direction. The vestibule window is closed base of the stirrup attached to the edges of the window using annular ligament. In the area of the posterior-inferior edge of the promontory there is snail window niche, protracted secondary tympanic membrane. 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.

Topography of the facial nerve . Joining with n. statoacousticus And n. intermedius to the internal ear 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 petrosal nerve, 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, 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, reaching the protrusion of the horizontal semicircular canal on the inner wall, at the level pyramidal elevation changes its direction to vertical (second knee) passes through the stylomastoid canal and through the opening of the same name exits to the base of the skull. In the immediate vicinity of the pyramidal eminence, the facial nerve gives off a branch to stapedius muscle, here it departs from the trunk of the facial nerve drum string. It passes between the malleus and the incus through the entire tympanic cavity from above the eardrum and exits through fissura petrotympanica, giving taste fibers to the anterior 2/3 of the tongue on its side, secretory fibers to salivary gland and fibers to nerves choroid plexuses. Anterior wall of the tympanic cavity- tubal or carotid . The upper half of this wall is occupied by two openings, the larger of which is the tympanic opening of the auditory tube. , above which the hemicanal of the tensor tympani muscle opens . In the lower section, the anterior wall is formed by a thin bone plate separating the trunk with the inner carotid artery, passing in the channel of the same name.

Posterior wall of the tympanic cavity- mastoid . In its upper section there is a wide passage (aditus ad antrum), through which the epitympanic space communicates with cave- permanent cell 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 elevation, 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.

Top wall- roof of the tympanic cavity. This is a bony plate that separates the tympanic cavity from the middle cavity. cranial fossa. Sometimes this plate contains dehiscences, due to which the hard meninges The middle cranial fossa is in direct contact with the mucous membrane of the tympanic cavity.

The lower wall of the tympanic cavity- jugular - borders on the underlying bulb jugular vein. 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.

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.

In the tympanic cavity there are three auditory ossicles and two intraauricular muscles. The chain of auditory ossicles consists of interconnected joints:

* 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 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 stirrup has a base, two legs, a neck and a head. 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 accommodative 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

77. Anatomy of the membranous labyrinth

Membranous labyrinth is a closed system of cavities and canals, basically repeating the shape of the bone labyrinth. The space between the membranous and bony labyrinth is filled with perilymph. 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.

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 disruption of its absorption can lead to increased intralabyrinth pressure.

From an anatomical and functional point of view, in inner ear There are two receptor apparatuses:

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 the cochlear duct is located in the cochlea between the scala vestibuli and the scala tympani. In cross-section, the cochlear duct has a triangular shape: it is formed by the vestibule, tympanic and outer walls. The upper wall faces the staircase of the vestibule and is formed by a thin, flat epithelial cells vestibular (Reisner's) membrane.

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 opposite wall of the bony cochlea, where the cochlear duct is located inside the cochlea. spiral ligament, the upper part of which, rich in blood vessels, is called vascular strip. The basilar membrane has an extensive network of capillaries blood vessels and represents 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 organ of corti- peripheral receptor auditory analyzer.

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 to the inner pillar cells is a row of inner hair cells; Outside the outer pillar cells are the outer hair cells. Hair cells synapse with peripheral nerve fibers emanating from the bipolar cells of the spiral ganglion. Supporting cells The organ of Corti performs supporting and trophic functions. Between the cells of the organ of Corti there are intraepithelial spaces filled with fluid called cortilymph.

Above the hair cells of the organ of Corti is located cover membrane, which, like the basilar 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. 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.

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 almost completely fill the bone ampullae. 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, 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 movement of endolymph during angular acceleration towards the ampulla or smooth knee of the semicircular canal leads to irritation of neuroepithelial cells.

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 are small elevations on the inner surface of both sacs, lined with neuroepithelium. 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 big number 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 in neuroepithelial hair cells. The elliptical and spherical sacs are connected to each other through a thin tubule , which has a branch - the endolymphatic duct . 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 , 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 approaches each sensitive cell nerve fibers, therefore, the death of one of these fibers does not entail cell death.

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

Features of the blood supply to the labyrinth are that the branches of the labyrinthine artery do not have anastomoses with vascular system middle ear, Reissner's 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.

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

78. Tuning fork methods for studying the auditory analyzer (Rine’s experiment, Weber’s experiment).

Qualitative tuning fork tests are used as a method of differential express diagnosis of disorders of the mechanism of sound conduction and sound perception. For this, “tuning forks C128 and C2048 are used. The study begins with a low-frequency tuning fork C128. Holding the tuning fork by the stem with two fingers, striking the jaws against the tenor of the palm causes it to vibrate. The S-2048 tuning fork is set into vibration by abruptly squeezing the jaws with two fingers or by clicking a nail. The sounding tuning fork is brought to the external auditory canal of the subject at a distance of 0.5 cm and held in such a way that the jaws oscillate in the plane of the axis of the auditory canal. Starting from the moment the tuning fork is struck, a stopwatch measures the time during which the patient hears its sound. After the subject stops hearing the sound, the tuning fork is moved away from the ear and brought closer again without exciting it again. As a rule, after such a distance from the ear of the tuning fork, the patient hears the sound for a few seconds. The final time is based on the last answer. A study is carried out similarly with a tuning fork C2048, the duration of perception of its sound through the air is determined. Bone conduction study. Bone conductivity is examined with a C128 tuning fork. This is due to the fact that the vibration of tuning forks with a lower frequency is felt by the skin, and tuning forks with a higher frequency are heard through the air by the ear. The sounding tuning fork C128 is placed perpendicularly with the stem on the mastoid area. The duration of perception is also measured with a stopwatch, counting the time from the moment the tuning fork is excited. If sound conduction is impaired (conductive hearing loss), the perception through the air of a low-sounding tuning fork C128 deteriorates; when studying bone conduction, the sound is heard longer. Impaired perception through the air of a high tuning fork C2048 is accompanied mainly by damage to the sound-receiving apparatus (sensorineural hearing loss). The duration of the sound of C2048 through air and bone also decreases proportionally, although the ratio of these indicators remains, as normal, 2:1. Qualitative tuning fork tests are carried out for the purpose of differential express diagnosis of damage to the sound-conducting or sound-receiving sections of the auditory analyzer. For this purpose, experiments are carried out by Rinne, Weber, Jelle, Federice. When performing these tests (experiments), one bass tuning fork C 128 is used.

1.Weber's experience- assessment of sound lateralization. A tuning fork is placed on the patient's head with its stem and asked to say which ear hears the sound louder. In case of unilateral damage to the sound-conducting apparatus ( sulfur plug in the ear canal, inflammation of the middle ear, perforation of the eardrum, etc.) lateralization of sound into the affected ear is observed; with bilateral damage - towards the worse hearing ear. Impaired sound perception leads to lateralization of sound into the healthy or better hearing ear.

2. Rinne's experience- comparison of the duration of perception of bone and air conduction. A low-frequency tuning fork is installed with a stem on the mastoid process. After the perception of sound through the bone ceases, it is brought with jaws to the ear canal. Normally, a person hears a tuning fork through the air longer (Rinne’s experience is positive). When sound perception is impaired, bone and air conduction deteriorate proportionally, so Rinne's experience remains positive. If sound transmission with normal auditory receptor function suffers, then sound through bone is perceived longer than through air (Rinne’s negative experience).

79. Esophagoscopy, tracheoscopy, bronchoscopy (indications and technique).

Esophagoscopy makes it possible to directly examine the inner surface of the esophagus using a rigid esophagoscope or flexible fiberscope. Using esophagoscopy, it is possible to determine the presence of foreign bodies and remove them, diagnose tumors, diverticula, cicatricial and functional stenoses, carry out a number of diagnostic (biopsy) and medical procedures(opening an abscess for periesophagitis, introducing a radioactive capsule for esophageal cancer, bougienage of scar strictures, etc.). Esophagoscopy is divided into urgent and planned. The first is carried out when providing emergency care(foreign bodies, food blockage) and often without a preliminary detailed clinical examination of the patient. Planned esophagoscopy is carried out in the absence emergency indications after a thorough special, related to a specific disease, and general clinical examination of the patient. Esophagoscopy is carried out in a specially adapted darkened room in the presence of a convenient table, electric suction and means for introducing washing liquids into the esophagus. The endoscopy room must have a tracheotomy set, appropriate means for infiltration anesthesia and resuscitation. For esophagoscopy for persons of different ages Different sizes of endotracheal tubes are needed. So, for children under 3 years old, a tube with a diameter of 5-6 mm and a length of 35 cm is used; Adults often use tubes of larger diameter (12-14 mm) and a length of 53 cm. Indications for esophagoscopy: esophagoscopy (fibroesophagoscopy) is carried out in all cases when there are signs of disease of the esophagus and it is necessary either to establish their nature, or to carry out appropriate therapeutic manipulation, for example, removal of foreign bodies, emptying of a diverticulum filled with food masses, removal of food blockage, etc. The indication for esophagoscopy is the need biopsies. Contraindications to esophagoscopy in urgent situations it practically does not exist, except for those cases when this procedure itself can be dangerous due to its severe complications, for example, with an embedded foreign body, mediastinitis, myocardial infarction, cerebral stroke.. General contraindications most often caused by the presence of decompensation of functions of cardio-vascular system, asthmatic condition, hypertensive crisis, severe general and cerebral atherosclerosis, acute disorder cerebral circulation. Regional contraindications are caused by diseases of organs adjacent to the esophagus (aortic aneurysm, compression and deformation of the trachea, inflammatory common and specific diseases of the pharynx and trachea, bilateral stenosing paralysis of the larynx, mediastinitis, massive periesophageal adenopathy, etc.). In some cases, esophagoscopy is difficult with low mobility or deformation of the spine in the cervical or thoracic region, with a short neck, ankylosis or contracture of one or both temporomandibular joints, trismus, etc. Local contraindications are caused by acute banal or specific esophagitis. For chemical burns of the esophagus, esophagoscopy is permissible only on the 8-12th day, depending on the depth of damage to the wall of the esophagus and the general intoxication syndrome. Esophagoscopy technique. Preparing the patient for esophagoscopy begins the day before: prescribe sedatives, sometimes tranquilizers, at night - sleeping pills. Limit drinking and exclude dinner. It is advisable to carry out planned esophagoscopy in the first half of the day. On the day of the procedure, food and liquid intake is excluded. 30 minutes before the procedure, morphine is prescribed subcutaneously in a dose appropriate to the patient’s age (children under 3 years of age are not prescribed; 3-7 years - an acceptable dose of 0.001-0.002 g; 7-15 years - 0.004-0.006 g; adults - 0.01 g ). At the same time, a solution of atropine hydrochloride is administered subcutaneously: children from 6 weeks are prescribed a dose of 0.05-015 mg, adults - 2 mg. Anesthesia. To carry out esophagoscopy and, especially, fibroesophagoscopy, local anesthesia is used in the vast majority of cases, and only pulverization or lubrication of the mucous membrane of the pharynx, laryngopharynx and the entrance to the esophagus with a 5-10% solution of cocaine hydrochloride up to 3-5 times with intervals of 3-5 minutes is sufficient. To reduce the absorption of cocaine and potentiate its anesthetic effect, a solution of adrenaline is usually added to its solutions (per 5 ml of cocaine solution, 3-5 drops of a 0.1% solution of adrenaline hydrochloride). Position of the patient. To insert an esophagoscopic tube into the esophagus, it is necessary that the anatomical curves of the spine and the cervicofacial angle be straightened. There are several patient positions for this. V.I. Voyachek (1962) writes that esophagoscopy is performed in a sitting, lying or knee-elbow position, while he preferred the method of lying on the stomach with the leg part of the operating table slightly elevated. In this position, it is easier to eliminate the flow of saliva into the respiratory tracts and the accumulation of gastric juice in the esophagoscope tube. In addition, orientation when inserting the tube into the esophagus is easier.

Tracheobronchoscopy The examination of the trachea and bronchi is carried out with diagnostic and therapeutic purpose with the same instruments used to examine the esophagus. Diagnostic examination trachea and bronchi is indicated in cases of respiratory dysfunction in the presence of neoplasms; the occurrence of tracheoesophageal fistula, atelectasis (any localization), etc. For therapeutic purposes, tracheobronchoscopy is used in otorhinolaryngology mainly in the presence of foreign bodies and scleroma, when infiltrates or a membrane of scar tissue form in the subglottic cavity. In this case, the bronchoscopic tube is used as a bougie. In therapeutic and surgical practice, tracheobronchoscopy is one of the measures in the treatment of abscess pneumonia and lung abscess. Plays no less important role instrumental study lungs in the practice of treating pulmonary tuberculosis. Depending on the level of insertion, the tubes are divided into upper and lower tracheobronchoscopy . When in top tracheobronchoscopy, the tube is inserted through the mouth, pharynx and larynx, in the lower case - through a pre-formed tracheotomy hole (tracheostomy ). Lower Tracheobronchoscopy is performed more often in children and people who already have a tracheostomy. The anesthesia technique deserves special attention. Currently, preference should be given to general anesthesia (anesthesia), especially since the doctor is armed with special respiratory and bronchoscopes (Friedel system). In children, examination of the trachea and bronchi is carried out only under anesthesia. In connection with the above, the introduction of anesthesia is carried out in the operating room with the patient lying on his back with his head thrown back. Advantages of general anesthesia over local anesthesia consist in the reliability of pain relief, the exclusion of mental reactions in the subject, relaxation of the bronchial tree, etc. Technique for introducing a tracheobronchoscopic tube. The patient is on the operating table in a supine position with the shoulder girdle raised and head thrown back. Holding with the fingers of your left hand lower jaw with the mouth open, under visual control (through the bronchoscope tube), the bronchoscope is inserted through the corner of the mouth into its cavity. The distal end of the tube should be located strictly at midline oropharynx. The tube is slowly advanced forward, pressing on the tongue and epiglottis. At the same time, the glottis becomes clearly visible. By rotating the handle, the distal end of the tube is turned 45° and inserted into the trachea through the glottis. The examination begins with the walls of the trachea, then the bifurcation area is examined. Under visual control, the tube is inserted alternately into the main and then into the lobar bronchi. Inspection of the tracheobronchial tree continues when the tube is removed. Foreign bodies are removed and pieces of tissue are taken for histological examination using a special set of forceps. Suction is used to remove mucus or pus from the bronchi. After this manipulation, the patient should be under the supervision of a doctor for 2 hours, since during this period laryngeal edema and stenotic breathing may occur

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

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

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

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

Rice. 3. Auditory ossicles.

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

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

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

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

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

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

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

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

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

Mastoid temporal bone located behind auricle and external auditory canal.

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

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

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

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

The main part of the middle ear is the tympanic cavity - a small space with a volume of about 1 cm³ located in the temporal bone. There are three auditory ossicles: the malleus, the incus and the stirrup - they transmit sound vibrations from the outer ear to the inner ear, simultaneously amplifying them.

The auditory ossicles, as the smallest fragments of the human skeleton, represent a chain that transmits vibrations. The handle of the malleus is closely fused with the eardrum, the head of the malleus is connected to the incus, and that, in turn, with its long process, is connected to the stapes. The base of the stapes closes the window of the vestibule, thus connecting to the inner ear.

The middle ear cavity is connected to the nasopharynx through the Eustachian tube, through which the average air pressure inside and outside the eardrum is equalized. When external pressure changes, the ears sometimes become blocked, which is usually resolved by yawning reflexively. Experience shows that ear congestion is resolved even more effectively swallowing movements or if at this moment you blow into a pinched nose.

Inner ear

Of the three sections of the organ of hearing and balance, the most complex is the inner ear, which, due to its intricate shape, is called the labyrinth. The bony labyrinth consists of the vestibule, cochlea and semicircular canals.

Anatomy of the ear:
Outer ear:
1. Leather
2. Auditory canal
3. Auricle
Middle ear:
4. Eardrum
5. Oval window
6. Hammer
7. Anvil
8. Stirrup
Inner ear:
9. Semicircular canals
10. Snail
11. Nerves
12. Eustachian tube

U standing man the cochlea is in front, and the semicircular canals are behind, with a cavity located between them irregular shape- vestibule. Inside the bone labyrinth there is a membranous labyrinth, which has exactly the same three parts, but smaller in size, and between the walls of both labyrinths there is a small gap filled with a clear liquid - perilymph.

Each part of the inner ear performs a specific function. For example, the cochlea is the organ of hearing: sound waves that enter the internal auditory canal from the external auditory canal through the middle ear are transmitted in the form of vibration to the fluid that fills the cochlea. Inside the cochlea there is a main membrane (lower membranous wall), on which the organ of Corti is located - a cluster of special auditory hair cells that, through vibrations of the perilymph, perceive auditory stimuli in the range of 16-20,000 vibrations per second, convert them and transmit them to the nerve endings of a pair of cranial nerves - vestibulocochlear nerve; Next, the nerve impulse enters the cortical auditory center of the brain.

The vestibule and semicircular canals are the organs of the sense of balance and body position in space. The semicircular canals are located in three mutually perpendicular planes and are filled with translucent gelatinous fluid; inside the channels there are sensitive hairs immersed in liquid, and with the slightest movement of the body or head in space, the liquid in these channels shifts, puts pressure on the hairs and generates impulses in the endings of the vestibular nerve - the brain instantly receives information about changes in body position. The work of the vestibular apparatus allows a person to accurately navigate in space during the most complex movements - for example, jumping into the water from a springboard and at the same time turning over several times in the air; in the water, a diver instantly knows where the top is and where the bottom is.

The main organ of the sense of balance, body position in space, is vestibular apparatus. It is studied with special care by space physiology and medicine, since the normal well-being of astronauts during flight largely depends on it.

The vestibular apparatus is located in the inner ear, in the same place where the cochlea, the organ of hearing, is located. It consists of semicircular canals And otolithic apparatus .

The semicircular canals are located in three mutually perpendicular planes and are filled with translucent gelatinous fluid. With any movement of the body or head in space, especially when the body rotates, fluid shifts in these channels.

Inside the channels there are sensitive hairs immersed in liquid. When the fluid moves during movement, it puts pressure on the hairs, they bend a little, and this instantly causes impulses to appear in the endings of the vestibular nerve.

Otolith apparatus, unlike the semicircular canals, does not perceive rotational movements, but the beginning and end of uniform rectilinear motion, its acceleration or deceleration, and also (for weightlessness this is the main thing!) perceives changes in gravity.

The principle of operation of the otolith apparatus - the organ that perceives the force of gravity - gravity - is quite simple. It consists of two small sacs filled with gelatinous liquid. The bottom of the bags is covered nerve cells equipped with hairs. Small crystals of calcium salts are suspended in the liquid - otoliths . They constantly (after all, the force of gravity acts on them) presses on the hairs, as a result, the cells are constantly excited and impulses from them “run” along the vestibular nerve to the brain. This makes us always feel the force of gravity. When you move the head or body, the otoliths shift, and their pressure on the hairs instantly changes - information is sent to the brain via the vestibular nerve: “The position of the body has changed.”

Under very difficult conditions, astronauts have to determine the position of their body in space.

Only in space flight, when the force of gravity has disappeared, are the otoliths suspended in the fluid of the otolithic apparatus and cease to put pressure on the hairs. Only then does the sending of impulses to the brain, signaling the position of the body in space relative to the center of gravity, stop. Then a state of weightlessness sets in, in which the feeling of the earth, the feeling of heaviness, to which the organism of animals and humans has adapted over millions of years of evolution, disappears.

There cannot be complete weightlessness on Earth. But in the depths of the waters of the oceans and seas, where the first living particles of protoplasm were born, the force of gravity was minimal. Delicate organisms were protected from the force of gravity. When the first living creatures came out of the water onto land, they were forced to adapt to this force. In addition, it was necessary to know exactly the position of the body in space. Animals began to need a perfect vestibular apparatus.

In space, the otolithic apparatus is turned off, but the body is accustomed to gravity. Therefore, K. E. Tsiolkovsky put forward the idea of protecting the astronaut from weightlessness: “On a spaceship it is necessary to create an artificial force of gravity due to centrifugal force.” Now scientists agree that if such “cosmic gravity” is to be created, then it must necessarily be several times less than earthly gravity.

For athletes, pilots, sailors and astronauts, the normal functioning of the vestibular system is extremely important. After all, they the most difficult conditions you have to determine the position of your body in space.

Stereophony or Stereo sound(from the ancient Greek words “stereoros” - solid, spatial and “background” - sound) - recording, transmission or reproduction of sound, in which auditory information about the location of its source is preserved by laying out the sound through two (or more) independent audio channels. In mono audio, the audio signal comes from one channel.

Stereophony is based on the ability of a person to determine the location of a source by the difference in the phases of sound vibrations between the ears, achieved due to the finiteness of the speed of sound. In stereophonic recording, recording is carried out from two microphones separated by some distance, each using a separate (right or left) channel. The result is the so-called "panoramic sound" There are also systems using a larger number of channels. Systems with four channels are called quadraphonic.

Tympanic cavity, cavitas tympanica , is a slit-like cavity in the thickness of the base of the pyramid of the temporal bone. It is lined with a mucous membrane that covers six of its walls and continues posteriorly into the mucous membrane of the cells of the mastoid process of the temporal bone, and in front into the mucous membrane of the auditory tube.

Outer membranous wall, paries membranaceus, The tympanic cavity is formed over a greater extent by the inner surface of the eardrum, above which the upper wall of the bony part of the auditory canal takes part in the formation of this wall.

Inner labyrinth wall, paries labyrinthicus, The tympanic cavity is at the same time the outer wall of the vestibule of the inner ear.

In the upper part of this wall there is a small depression - the dimple of the window of the vestibule, fossula fenestrae vestibuli, in which there is a window of the vestibule, fenestra vestibuli, - an oval hole covered by the base of the stapes.

In front of the dimple of the window of the vestibule, on the inner wall, the septum of the muscular-tubal canal ends in the form of a cochlear process, processus cochleariformis.

Below the window of the vestibule there is a rounded elevation - a cape, promontorium, on the surface of which there is a vertically running groove of the cape, sulcus promontorii.

Below and posterior to the promontory there is a funnel-shaped dimple for the window of the cochlea, fossula fenestrae cochleae, where the round window of the cochlea is located, fenestra cochleae .

The dimple of the cochlear window is limited above and behind by a bone ridge - the promontory support, subiculum promontorii.

The window of the cochlea is closed by the secondary tympanic membrane, membrana tympani secundaria. It is attached to the rough edge of this hole - the comb of the cochlea window, crista fenestrae cochleae.

Above the fenestra of the cochlea and behind the promontory is a small depression called the sinus tympani, sinus tympani.

Upper tegmental wall, paries tegmentalis, the tympanic cavity is formed by the bone substance of the corresponding section of the petrous part of the temporal bone, which due to this received the name of the roof of the tympanic cavity, tegmen tympani. In this place, the tympanic cavity forms an upward-facing supratympanic recess, recessus epitympanicus, and its deepest section is called the dome part, pars cupularis.

The lower wall (bottom) of the tympanic cavity called the jugular wall paries jugularis, due to the fact that the bone substance of this wall takes part in the formation of the jugular fossa. This wall is uneven and contains air-filled tympanic cells, cellulae tympanicae, as well as the opening of the tympanic tubule. The jugular wall bears a small awl-shaped projection, prominentia styloidea, being the base of the styloid process.

Posterior mastoid wall, paries mastoideus, the tympanic cavity has an opening - the entrance to the cave, aditus ad antrum. It leads to the mastoid cave, antrum mastoideum, which in turn communicates with the mastoid cells, cellulae mastoideae.

On the medial wall of the entrance there is an elevation - a protrusion of the lateral semicircular canal, prominentia canalis semicircularis lateralis, below it there is an arched protrusion of the facial canal running from front to back and downwards, prominentia canalis facialis.

In the upper medial section of this wall there is a pyramidal eminence, eminentia pyramidalis, with the stapedius muscle embedded in its thickness, m. stapedius

On the surface of the pyramidal eminence there is a small depression - the fossa of the anvil, fossa incudis, into which the short leg of the anvil enters.

Somewhat below the incus fossa, on the anterior surface of the pyramidal eminence, under the prominence of the facial nerve, is the posterior sinus, sinus posterior, and below, above the styloid protrusion, the tympanic aperture of the canaliculus of the tympanic chord opens, apertura tympanica canaliculi chordae tympani.

The anterior carotid wall, paries caroticus, of the tympanic cavity bears the tympanic cells, cellulae tympanicae. Its lower part is formed by bone substance back wall canal of the internal carotid artery, above which is the tympanic opening of the auditory tube, ostium tympanicum tubae auditivae.

Clinicians conventionally divide the tympanic cavity into three sections: lower, middle and upper.

TO lower section tympanic cavity (hypotympanum) part of it is attributed between the lower wall of the tympanic cavity and the horizontal plane drawn through the lower edge of the eardrum.

Middle section tympanic cavity (mesotympanum) takes most tympanic cavity and corresponds to that part of it that is limited by two horizontal planes drawn through the lower and upper edges of the tympanic membrane.

Upper section tympanic cavity (epitympanum) located between the upper border of the middle section and the roof of the tympanic cavity.

16.Types of innervation of the nasal cavity.

17. Chronic purulent mesotympanitis.

18. Study of the vestibular analyzer with a rotational test.

19. Allergic rhinosinusitis.

20. Physiology of the nasal cavity and paranasal sinuses.

21. Tracheotomy (indications and technique).

1. Current or threatened obstruction of the upper respiratory tract

22. Deviated nasal septum.

23.Structure of the lateral wall of the nasal cavity

24. Topography of the recurrent nerve.

25. Indications for radical surgery on the middle ear.

26. Chronic laryngitis.

27. New treatment methods in otorhinolaryngology (laser, surgical ultrasound, cryotherapy).

28. The founders of domestic otorhinolaryngology N.P. Simanovsky, V.I. Voyachek

29. Anterior rhinoscopy (technique, rhinoscopic picture).

30. Methods of treatment of acute laryngo-tracheal stenoses.

31. Diffuse labyrinthitis.

32. List the intracranial and orbital complications of inflammatory diseases of the paranasal sinuses.

33. Syphilis of the upper respiratory tract.

34. Characteristics and forms of chronic purulent otitis media.

35. Differential diagnosis of diphtheria of the pharynx and lacunar tonsillitis.

36. Chronic pharyngitis (classification, clinical picture, treatment).

37. Cholesteatoma of the middle ear and its complications.

38. Cyst-like distension of the paranasal sinuses (mucocele, pyocele).

39. Differential diagnosis of boil of the external auditory canal and mastoiditis

40. Clinical anatomy of the external nose, nasal septum and floor of the nasal cavity.

41. Acute laryngotracheal stenoses.

42. Apical-cervical forms of mastoiditis.

43. Chronic tonsillitis (classification, clinical picture, treatment).

44. Paralysis and paresis of the larynx.

45. Mastoidectomy (purpose of operation, technique).

46. Clinical anatomy of the paranasal sinuses.

47. Topography of the facial nerve.

48. Principles of treatment of patients with otogenic intracranial complications.

49. Indications for tonsillectomy.

50. Laryngeal papillomas in children.

51. Otosclerosis.

52. Diphtheria of the pharynx

53. Purulent otitis media in infectious diseases

54. The influence of hyperplasia of the pharyngeal tonsil on a growing organism.

55. Smell disorders.

56. Chronic stenosis of the larynx.

58. Clinic of acute otitis media. Outcomes of the disease.

59. Meso-epipharingoscopy (technique, visible anatomical formations).

60. Otohematoma and perechondritis of the auricle

61. Diphtheria of the larynx and false croup (differential diagnosis).

62. The principle of reconstructive operations on the middle ear (tympanoplasty).

63. Conservative and surgical methods of treating patients with exudative otitis media.

64. Sound-conducting and sound-perceiving system of the auditory analyzer (list the anatomical formations).

65. Resonance theory of hearing.

66. Allergic rhinitis.

67. Cancer of the larynx.

69. Peritonsillar abscess

70. Chronic purulent epitympanitis.

71. Physiology of the larynx.

72. Retropharyngeal abscess.

73.Sensorineural hearing loss (etiology, clinical picture, treatment).

74.Vestibular nystagmus, its characteristics.

75. Fracture of the nasal bones.

76. Clinical anatomy of the tympanic cavity.

78. Tuning fork methods for studying the auditory analyzer (Rine’s experiment, Weber’s experiment).

79. Esophagoscopy, tracheoscopy, bronchoscopy (indications and technique).

80. Early diagnosis of laryngeal cancer. Tuberculosis of the larynx.

81. Otogenic thrombosis of the sigmoid sinus and septicopyemia.

82. Classification of chronic tonsillitis, adopted at the VII Congress of Otorhinolaryngologists in 1975.

83. Acute rhinitis.

84. Clinical anatomy of the external ear and tympanic membrane

85. Cartilages and ligaments of the larynx.

86. Chronic frontal sinusitis.

87. Radical surgery on the middle ear (indications, main stages).

88. Meniere's disease

89. Otogenic abscess of the temporal lobe of the brain

90. Muscles of the larynx.

91. Helmholtz's theory.

92. Laryngoscopy (methods, technique, laryngoscopic picture)

93. Foreign bodies of the esophagus.

94. Juvenile fibroma of the nasopharynx

95. Exudative otitis media.

96. Chronic rhinitis (clinical forms, methods of conservative and surgical treatment).

97. Foreign bodies of the bronchi.

98. Chemical burns and cicatricial stenosis of the esophagus.

99. Otogenic leptomeningitis.

100. Foreign bodies of the larynx.

101. The structure of the receptors of the auditory and vestibular analyzers.

102. Basic principles of treatment.

76.Clinical anatomy tympanic cavity.

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

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

Medial (internal) The wall of the tympanic cavity separates the middle and inner ear. 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 . The tympanic (or Jacobson) nerve participates in the formation of the tympanic plexus , nn. trigeminus, facialis, as well as sympathetic fibers from plexus caroticus internus.

Topography facial nerve . 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 petrosal nerve, 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, 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, reaching the protrusion of the horizontal semicircular canal on the inner wall, at the level pyramidal elevation changes its direction to vertical (second knee) passes through the stylomastoid canal and through the foramen of the same name 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, here it departs from the trunk of the facial nerve drum string. It passes between the malleus and the incus through the entire tympanic cavity from above the eardrum and exits through fissura petrotympanica, giving taste fibers to the anterior 2/3 of the tongue on its side, secretory fibers to the salivary gland and fibers to the nerve vascular plexuses. Front walltympanic cavity- tubal or carotid . The upper half of this wall is occupied by two openings, the larger of which is the tympanic opening of the auditory tube. , above which the hemicanal of the tensor tympani muscle opens . 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.

Posterior wall of the tympanic cavity - mastoid . In its upper section there is a wide passage (aditus ad antrum), through which the epitympanic space communicates with cave- 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 elevation, 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.

Top wall- roof of the tympanic cavity. This is a bony plate that separates 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.

The lower wall of the tympanic cavity - jugular - borders on the underlying bulb of the jugular vein . 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.

In the tympanic cavity there are three auditory ossicles and two intraauricular muscles. The chain of auditory ossicles consists of interconnected joints:

* malleus (malleus); * anvil (incus); * stirrup (stapes).

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.

77. Anatomy of the membranous labyrinth

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 located in the cochlea between the scala vestibule and scala tympani. In cross-section, the cochlear duct has a triangular shape: it is formed by the vestibule, tympanic and outer walls. The upper wall faces the scala vestibule and is formed by thin, flat epithelial cells vestibular (Reisner's) membrane.

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 opposite wall of the bony cochlea, where the cochlear duct is located inside the cochlea. spiral ligament, the upper part of which, rich in blood vessels, is called vascular strip. 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 organ of corti- peripheral receptor of the auditory analyzer.

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 to the inner pillar cells is a row of inner hair cells; Outside the outer pillar cells are the 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.

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 are small elevations on the inner surface of both sacs, lined with neuroepithelium. 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 in neuroepithelial hair cells. The elliptical and spherical sacs are connected to each other through a thin tubule , which has a branch - the endolymphatic duct . 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 , 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.

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.

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