Clonus of the tensor tympani muscle. Meaning of tensor tympani muscle (m
The middle ear is located in temporal bone and is formed by three air cavities communicating with each other.
The middle ear (auris media) consists of tympanic cavity(cavitas tympani), auditory tube(tuba auditiva), and caves and cells of the mastoid process(antrum et cellulae processus mastoideae).
Tympanic cavity(cavitas tympani) has a vertical dimension of 10 mm and a transverse dimension of 5 mm. It is shaped like a cube. It is divided into three sections: lower (hypotympanum), middle (mesotympanum), located between horizontal planes, conventionally drawn through the lower and upper edges eardrum, and upper (epitympanum). The tympanic cavity has six walls. Lateral wall– membranous (paries membranaceus), formed by the tympanic membrane and the bone plate (lateral wall of the attic). Front wall- carotid (paries caroticus), present only in the lower half of the tympanic cavity, in the upper part there is an opening of the auditory (Eustachian) tube. This wall separates the tympanic cavity from the carotid canal, which contains the internal carotid artery. Bottom wall– jugular (paries jugularis), located 2-3 mm below the level of attachment of the tympanic membrane, under it is the bulb of the jugular vein. The tympanic nerve (branch of the IX pair), as well as the tympanic artery and vein, pass through this wall into the tympanic cavity. Back wall tympanic cavity - mastoid (paries mastoideus), on it there is a pyramidal eminence in which the stapedius muscle (m. stapedius) is placed, outside of it there is an opening of the channel of the tympanic chord (branch of the VII pair), in the depth back wall lies the facial canal with the facial nerve, in the area of the epitympanic recess there is an entrance to the mastoid cave . Medial wall– labyrinthine (paries labirinthicus), has a bony protrusion with a diameter of about 8 mm – promontory (promontorium). The promontory is formed by the lateral wall of the cochlea's dome. On its surface there are grooves of the nerves of the tympanic (Jacobson's) plexus, carotid-tympanic nerves, in the area of the posteroinferior edge there is a window of the cochlea, closed by the secondary tympanic membrane, in the area of the anterior-inferior edge there is a window of the vestibule, closed by the base of the stapes. Anterior to it is the tendon of the tensor tympani muscle. . Top wall– tegmental (paries tegmen talis), is part of the bottom of the middle cranial fossa. In this part there are digestions (cracks), through which purulent processes can spread.
In the upper part of the tympanic cavity there are auditory ossicles (ossicula auditus): malleus (malleus), incus (incus), stirrup (stapes), which, thanks to ligaments and joints, form a movable chain between the tympanic membrane and the window of the vestibule. The malleus, located externally, has a head, a handle and two processes: a thin and long anterior process and a short lateral one. The lower end of the handle is fused with the eardrum. The incus is the middle link in the chain of auditory ossicles, consists of a body and two legs - short and long. The body of the incus and the head of the malleus connected to it are located in the supratympanic recess, or attic, located between the upper wall of the tympanic cavity and the tendon of the tensor tympani muscle. The short leg of the incus is connected by means of a ligament to the posterior wall of the tympanic cavity, and the long leg is articulated with the stirrup. The stapes consists of a head connected through a joint to the incus, anterior and posterior legs and a base. The legs and base limit the opening in which the stapes membrane is located. The base is fixed in the window of the vestibule by the annular ligament. The movements of the auditory ossicles are provided by the intraauricular muscles: the tensor tympani muscle and the stapedii muscle.
The walls of the tympanic cavity and the auditory ossicles are covered with a mucous membrane, which forms several folds and passes into the mucous membrane of the auditory tube and the cells of the mastoid process.
Anterior to the tympanic cavity is located auditory (Eustachian) tube (tuba auditiva) connecting it to the nasopharynx. The length of the pipe connecting the tympanic cavity with the nasopharynx is 34-45 mm. It has bone (1/3) and cartilaginous (2/3) parts. At the point of transition from one to another, the narrowest place (up to 1 mm) is noted - the isthmus. The pharyngeal opening of the auditory tube (ostium pharyngeum tubae auditivae) is located on the lateral wall of the pharynx at the level of the posterior end of the inferior turbinate. The tympanic opening (mouth) of the auditory tube (ostium tympanicum tubae auditivae) occupies the anterior - upper part of the carotid wall. In an adult, the tympanic opening is approximately 2 cm above the pharyngeal opening, as a result of which the Eustachian tube is directed downwards, inwardly and anteriorly towards the pharynx. The surface layer of the mucous membrane lining the wall of the auditory tube is represented by ciliated epithelium, which protects the middle ear from the penetration of infectious agents from the nasopharynx. In the mucous membrane of the cartilaginous section there is a large number of mucous glands. At the moment of swallowing, the lumen of the tube opens, which ensures equalization of air pressure between the tympanic cavity and external environment. The change in the lumen of the auditory tube is regulated by the work of the muscle that strains the palatine curtain (m. tensoris veli palatine), attached to the lateral wall of the tube and the tubopharyngeal muscle (m. salpingopharyngeus), which is attached to the lower wall in the area of the pharyngeal opening on one side and to the upper the horn of the thyroid cartilage on the other side, part of the fibers of this muscle is woven into the superior constrictor of the pharynx.
The bony part of the auditory tube is the lower hemicanal of the muscular tubal canal (canalis musculotubarius) of the temporal bone, and the upper hemicanal is occupied by the tensor tympani muscle. This muscle begins in the cartilaginous part of the auditory tube at the exit from the hemicanal into the tympanic cavity, the tendon m. tensoris tympani rotates around a small hook-shaped protrusion at the promontory of the cochlear process and attaches to the handle of the malleus.
System of cavities in the mastoid part of the temporal bone. The structure is individual, depending on age. These are accessory cavities of the tympanic cavity that perform a resonator function. The mastoid cave and cells (antrum et cellulae mastoideae) are lined with mucous membrane. The entrance to the cave from the tympanic cavity is located in the epitympanic recess in the area of the prominence of the lateral semicircular canal. The cave has an upper wall - a continuation of the roof of the tympanic cavity at the level of the temporal line, medial and posterior walls bordering the transverse sinus. The lower wall borders on other cells of the mastoid process. In fact, the mastoid cave is a continuation of the longitudinal axis of the epitympanic space and the lumen of the mouth of the auditory tube. Moreover, the anterior-lateral wall of the cave represents the posterior bony wall of the external auditory canal, the bottom of the cave is located at the level of the middle of the posterior bony wall of the external auditory canal. The largest cells are located under the cave in the mastoid process.
Innervation the middle ear is carried out mainly tympanic nerve (n. tympanicus – Jacobson nerve), which arises from the petrosal (inferior jugular) ganglion of the glossopharyngeal nerve. The sensitive portion of this nerve is formed by the peripheral processes of the pseudounipolar cells of this node. The central processes of these cells end on the interneurons of the nucleus of the solitary tract. The tympanic nerve contains preganglionic parasympathetic fibers, which are the axons of the cells of the inferior salivary nucleus. The tympanic nerve in the area of the petrosal fossa enters the canal of the same name, passes through it and penetrates the tympanic cavity through the lower aperture of the tympanic canaliculus (apertura inferior canaliculi tympani), the jugular wall. In the tympanic cavity, the nerve splits into the tympanic plexus (plexus tympanicus) - Jacobson's plexus. The plexus is located on the medial wall of the tympanic cavity. The nerves that form the plexus are located either in bone canals or in grooves. This plexus is joined by the sympathetic carotid-tympanic nerves (from the plexus of the internal carotid artery), passing into the cavity along the canals of the same name in the temporal bone. Postganglionic sympathetic fibers enter the tympanic cavity through the carotid-tympanic tubules and join the Jacobson plexus. The tympanic plexus also includes a connecting branch facial nerve(parasympathetic). As part of this plexus, the autonomic ganglia are designated, in which some of the preganglionic parasympathetic fibers are switched, and some pass in transit, forming the lesser petrosal nerve, leaving the tympanic cavity through the cleft of the lesser petrosal nerve. Thus, the mucous membrane of the tympanic cavity, the auditory tube to the isthmus, the mastoid cave and cells receive sensitive somatic innervation, secretory innervation, innervation of the vessels and nerves of the middle ear from the tympanic (Jacobson's) plexus.
The lesser petrosal nerve leaves the cranial cavity through the foramen lacerum, carrying with it sympathetic fibers from the internal carotid plexus. Preganglionic parasympathetic fibers are interrupted in the ear ganglion and postganglionic parasympathetic fibers as part of the auriculotemporal nerve (sensitive somatic) of the third branch of the trigeminal nerve approach the parotid salivary gland, providing its complete innervation. Relationship between innervation salivary gland and the tympanic cavity is the cause of increased salivation observed in diseases of the middle ear.
The sympathetic fibers of the carotid-tympanic nerves contain fibers from the nerve of the dilator pupillary muscle (from the superior cervical sympathetic ganglion). Therefore, their irritation on the side of the affected middle ear sometimes causes pupil dilation.
The tympanic chord (chorda tympani) transits through the tympanic cavity - this is a nerve that extends from the facial nerve in its lower section, formed by the peripheral processes of pseudounipolar cells of the geniculate ganglion and preganglionic parasympathetic fibers of the cells of the superior salivary nucleus. The tympanic string crosses the tympanic cavity, passing between the long process of the incus and the handle of the malleus. It leaves the tympanic cavity through an opening in the posterior wall, the temporal bone in its anterior section through the petrotympanic fissure (fissure petrotympanica) - Glaser's fissure, then continues its path to the lingual nerve of the third branch of the trigeminal nerve and to the autonomic submandibular node. At the node, preganglionic parasympathetic fibers switch and postganglionic fibers provide secretory innervation to the submandibular and sublingual salivary glands. Under conditions of pressure difference between the tympanic cavity and the external one, the tympanic membrane is retracted into the tympanic cavity, touches the tympanic chord, irritates it, thereby increasing salivation; the act of swallowing reflexively responds to excess saliva, during which the lumen of the cartilaginous part of the auditory tube expands (the tensor muscle contracts). velum palatine and tubopharyngeal muscle), the pressure is equalized.
Passes through the tympanic cavity in transit greater petrosal nerve (n. petrosus major). The nerve is formed by preganglionic parasympathetic fibers, which are the axons of the cells of the superior salivary and lacrimal nucleus. It branches off from the trunk of the facial nerve at the level of the first genu and then goes either in the bone canal of the upper wall of the tympanic cavity or freely. Leaves the cavity through the cleft of the canal of the greater petrosal nerve. Along the anterior surface of the pyramid of the temporal bone it is directed to the lacerated foramen, through which it leaves the cranial cavity. Having penetrated the outer base of the skull, it enters the pterygoid canal. In the canal it is joined by the sympathetic nerve from the internal carotid plexus - the deep petrosal nerve (n. petrosus profundus). The combined nerve is called the nerve of the pterygoid canal (n. canalis pterygoidei). Along the canal, the nerve penetrates into the pterygopalatine fossa, preganglionic parasympathetic fibers switch in the pterygopalatine node to postganglionic ones, and as part of the nodal branches of the maxillary nerve of the V pair, they and sympathetic postganglionic fibers reach the mucous glands of the oral cavity and nasal cavity according to the messages of the pterygopalatine fossa. The lacrimal gland is reached through the zygomatic nerve and the anastomosis between it and the lacrimal nerve. This “connection” helps explain the increased secretion of these glands during inflammatory processes in the middle ear.
Stapes nerve (n. stapedius), a thin stem, formed by the central processes of the cells of the motor nucleus of the facial nerve, branches off in the facial canal from the nerve in the area of the second knee, penetrates into the tympanic cavity, where it innervates the m. stapedius
The nerve of the muscle that strains the tympanic membrane (n. musculi tensoris tympani) and the nerve of the muscle that strains the veli palatine (n. musculi tensoris veli palatine) innervate the muscles of the same name. These are the motor branches of the mandibular nerve, V pair (trigeminal nerve). Tubalopharyngeus muscle (m. salpingopharyngeus) innervated by motor branches vagus nerve, part of the pharyngeal plexus.
MUSCLE THAT STRESSES THE TYMPANUM (M. TENSOR TYMPANI, PNA, BNA, JNA)
see List of anat. terms 837.
Medical terms. 2012
See also interpretations, synonyms, meanings of the word and what the MUSCLE THAT STRESSES THE TYMPAN EARDRUM (M. TENSOR TYMPANI, PNA, BNA, JNA) is in Russian in dictionaries, encyclopedias and reference books:
- MUSCLE in the Brief Church Slavonic Dictionary:
- shoulder, strength, strength, ... - MUSCLE in Medical terms:
(s) (musculus, -i, pna, bna, jna; syn. muscle) an organ that has the property of contractility, ensuring the movement of one or another element of a living organism: ... - P.N.A. in Medical terms:
(parisiana nomina anatomica) see Anatomical nomenclature of Paris ... - J.N.A. in Medical terms:
see Anatomical nomenclature Jena ... - BNA in Medical terms:
(baseler nomina anatomica) see Anatomical nomenclature Basel ... - MUSCLE in the Encyclopedic Dictionary:
, -y, w. An organ of the human and animal body, consisting of tissue capable of contracting under the influence of nerve impulses. II adj. muscular... - MUSCLE in the Complete Accented Paradigm according to Zaliznyak:
we"shtsa, we"shtsy, we"shtsy, we"shts, we"shtse, we"shtsam, we"shtsu, we"shtsy, we"shtsey, we"shtseyu, we"shtse, we"shtse, ... - MUSCLE in the Russian Synonyms dictionary:
abductor, adductor, antagonist, biceps, calf, constrictor, myocardium, muscle, meat, synergist, synergist, sphincter, triceps, flexor, extensor, ... - MUSCLE in the New Explanatory Dictionary of the Russian Language by Efremova:
- MUSCLE in Ozhegov’s Dictionary of the Russian Language:
an organ of the human and animal body consisting of tissue capable of contracting under the influence of nerve impulses Cardiac ... - MUSCLE in Ushakov’s Explanatory Dictionary of the Russian Language:
muscles, g. 1. An organ of movement in humans and animals, consisting of tissue capable of contracting and moving the tendons attached to it... - MUSCLE in Ephraim's Explanatory Dictionary:
muscle g. An organ of the body of animals and humans, consisting of tissue capable of contracting under the influence of nervous... - MUSCLE in the New Dictionary of the Russian Language by Efremova:
and. An organ of the body of animals and humans, consisting of tissue capable of contracting under the influence of nervous... - MUSCLE in the Bolshoi Modern explanatory dictionary Russian language:
and. An organ of the body of animals and humans, consisting of tissue capable of contracting under the influence of nervous... - NERVE OF THE MUSCLE TENSORIS TYMPANI (N. TENSORIS TYMPANI, PNA, BNA; N. MUSCULI TENSORIS TYMPANI, JNA) in Medical terms:
see List of anat. ... - FASCIA OF THE MUSCLE LEVELATTOR TESTIS (F. CREMASTERICA, PNA, BNA, JNA) in Medical terms:
see List of anat. ... - SPLEEN in Medical terms:
organ lymphatic system, located in abdominal cavity(in the left hypochondrium), performing the functions of hematopoiesis, antibody production, destruction of red blood cells and ... - LIGAMENT SUSPENDING THE PENIS (L. SUSPENSORIUM PENIS, PNA, BNA, JNA) in Medical terms:
see List of anat. ... - BORDER FROWS 1) (SULCUS LIMITANS, PNA, BNA, JNA; LNE) in Medical terms:
a paired longitudinal depression on the inner surface of the lateral wall of the neural tube, dividing it into alar (dorsolateral) and basal (ventrolateral) plates; 2) ... - FASCIA(S) (FASCIA, PNA, BNA, JNA; LAT. "BANDAGE", "BANDAGE") in Medical terms:
a sheath of dense fibrous connective tissue covering muscles, many internal organs, blood vessels and nerves; forms their fascial beds and... - JOINTS INTERPHALANGEAL HANDS AND FEET in Medical terms:
block-shaped S., formed by the heads and bases of adjacent phalanges of the fingers; in S. m. flexion and extension are possible... - CARPOMETACARPICUS POLLICIS, PNA, BNA; A. CARPOMETACARPICUS PRIMUS, JNA) in Medical terms:
saddle-shaped S., formed by the trapezium bone and the base of 1 metacarpal bone; in this S. abduction (in the plane of the palm), adduction, flexion, extension, ... - VESSEL(S) IN ANATOMY in Medical terms:
tubular formation through which blood moves or... - TESTICLE NETWORK in Medical terms:
a set of intertwined and interconnected tubular formations located in the mediastinum of the testicle; in S. i. straight seminiferous tubules open from... - CARDIAC IMPRESSION OF 1) LUNG in Medical terms:
depression on the medial surface right lung, corresponding to the location of the heart; 2) liver... - LIGAMENT SUSPENDING THE OVAR (L. SUSPENSORIUM OVARII, PNA, BNA) in Medical terms:
see List of anat. ... - LIGAMENT SUSPENDING THE MALLEI (L. SUSPENSORIUM MALLEI, PNA, BNA) in Medical terms:
see List of anat. ... - LIGAMENT SUSPENDING THE CLITOR (L. SUSPENSORIUM CLITORIDIS, PNA, BNA, JNA) in Medical terms:
see List of anat. ... - RIB(-A) (COSTA, -AE, PNA, BNA, JNA) in Medical terms:
paired long curved flat bones chest, consisting of the bone part and costal cartilage; a person has 12 pairs... - MUSCLE THAT STRESSES THE PALATINE (M. TENSOR VELI PALATINI PNA, BNA, JNA) in Medical terms:
see List of anat. ... - MUSCLE THAT STRESSES THE SOFT PALATE (M. TENSOR PALATI MOLLIS) in Medical terms:
see List of anat. terms... - HEARING
- S. is a special function of the ear, excited by oscillating bodies in the environment - air or water. In the hearing aid we... - HEARING
? S. is there a special function of the ear, excited by vibrating bodies in the environment? air or water. In the hearing aid we... - FIBROUS RING(S) in Medical terms:
1) - a set of ring-shaped collagen fibers that form the peripheral part of the intervertebral disc; 2) in Medical terms:
the muscular lining of the uterus, formed by smooth muscle cells, between the bundles of which there is loose connective tissue, rich in elastic... - TYMPANOMEATAL FLAP in Medical terms:
(anat. membrana tympani eardrum + meatus acusticus ear canal) L., containing the skin of the external auditory canal and the eardrum; used... - DENTAL ARCH in Medical terms:
(arcus dentalis, pna, bna, jna) arched row of tooth crowns; distinguish the upper (a. d. superior, PNA, BNA; a. d. maxillaris, ... - AUDITORY BONES in the Encyclopedic Dictionary of Brockhaus and Euphron:
(ossicula auditiva) - are located in the middle ear cavity of vertebrates and morphologically represent parts of the visceral skeleton (see Vertebrates). In amphibians... - AUDITORY BONES* in the Brockhaus and Efron Encyclopedia:
(ossicula auditiva) ? are located in the middle ear cavity of vertebrates and morphologically represent parts of the visceral skeleton (see Vertebrates). In amphibians... - TRETYAKOV LEONID APOLLONOVICH in the Brief Biographical Encyclopedia:
Tretyakov (Leonid Apollonovich) - ordinary professor at the Kazan Veterinary Institute, where he completed his course, was born in 1856. In 1888... - NUCLEUS(-A) 1 C. N. S. (NUCLEUS, PNA) in Medical terms:
accumulation of gray matter in a certain area of the c. n. pp., ensuring the implementation of certain ... - NUCLEUS OF THE THALAMUS VENTROLATERAL [N]. VENTROLATERALES (THALAMI), PNA in Medical terms:
a group of nuclei in the inferolateral part of the thalamus, which are the site of switching of afferent nerve pathways going to the parietal cortex... - PHRENIC NERVE NUCLEUS in Medical terms:
I., located in the anterior columns of the spinal cord at the level of III - V cervical segments; gives rise to motor fibers of the diaphragmatic... - MEDIUM THALAMUS NUCLEI in Medical terms:
group of Ya. thalamus adjacent to the wall III ventricle; includes paraventricular, rhomboid and connecting... - NUCLEI OF THE THALAMUS MEDIAL in Medical terms:
group of Ya, located in the medial part of the thalamus, sending nerve impulses in the cortex of the frontal lobe of the large... - POSTERIOR THALAMIC NUCLEI in Medical terms:
a group of cells located in the geniculate bodies and the thalamic cushion and forming the subcortical centers of vision and ... - EPICARD in Medical terms:
the outer serous membrane of the heart, which is a visceral plate...
Stapedius muscle
, m. stapedius. It begins in the bony canal on the posterior wall of the tympanic cavity, its tendon exits through the hole at the top of the pyramidal eminence and is attached to the head of the stapes. When the muscle contracts, the base of the stapes is pressed more tightly against the window of the vestibule, which promotes attenuation sound wave reaching inner ear. Inn.: stapedius nerve (branch of n. facialis). Rice. B.Mucous membrane of the tympanic cavity
, tunica mucosa cavitatis tympanicae. It consists of a single-layer squamous (cuboidal) epithelium and a thin lamina propria containing a large number of blood vessels.Posterior malleus fold
, plica mallearis posterior. Runs from the base of the hammer handle back to the top of the tympanic ring. Contains part of a drum string. Rice. G.Anterior malleus fold
, plica mallearis anterior. Runs from the base of the hammer handle forward to the top of the tympanic ring. Contains the anterior part of the chorda tympani, the anterior process of the malleus and lig. mallei anterius. Rice. G.Drum string fold
, plica chordae tympani. Connects the malleus folds at the neck of the malleus. Rice. G.7a.
Recesses of the eardrum
, recessus membranae tympaniсae. Pockets of the mucous membrane of the tympanic cavity.Anterior recess [tympanic membrane]
, recessus anterior. Located between the anterior malleus fold and the tympanic membrane. Rice. G.Superior recess [tympanic membrane] [[Prussian's pocket]]
, recessus superior []. On the lateral side it is limited by the loose part of the membrane, on the medial side by the head and neck of the malleus, as well as by the body of the incus. Rice. G.10.
Posterior recess [tympanic membrane]
, recessus posterior. Located between the posterior malleus fold and the tympanic membrane. Rice. G.11.
Anvil fold
, plica incudialis. Passes between the dome part of the supratympanic recess and the head of the incus or connects the short leg of the incus with the posterior wall of the tympanic cavity. Rice. G.12.
Stirrup fold
, plica stapedialis. Located between the posterior wall of the tympanic cavity and the stirrup, covering m. stapedius and stirrup. Rice. B.13.
Eustachian tube
, tuba auditoria (auditiva). An osteochondral tube, about 4 cm long, between the middle ear and the nasopharynx. Serves to bring air into the tympanic cavity. Rice. A , Rice. IN.14.
Tympanic opening of the auditory tube
, ostium tympanicum tubae auditoriae. It is located on the front wall of the tympanic cavity, slightly above its bottom. Rice. A.15.
Bone part of the auditory tube
, pars ossea tubae auditoriae. Its posterolateral (upper) part makes up approximately 1/3 of the entire length. It is located downward from the hemicanal of the tensor tympani muscle and ends with an opening located between the carotid canal and the foramen spinosum. Rice. A.16.
Isthmus of the auditory tube
, isthmus. Narrowing at the junction of the cartilaginous part of the tube into the bone. Rice. A.17.
Air cells
, cellulae pneumaticae. Small depressions in the wall of the bony part of the tube.The middle ear is located in the temporal bone and is formed by three interconnected air cavities.
The middle ear (auris media) consists of tympanic cavity(cavitas tympani), auditory tube(tuba auditiva), and caves and cells of the mastoid process(antrum et cellulae processus mastoideae).
Tympanic cavity(cavitas tympani) has a vertical dimension of 10 mm and a transverse dimension of 5 mm. It is shaped like a cube. It is divided into three sections: lower (hypotympanum), middle (mesotympanum), located between horizontal planes conventionally drawn through the lower and upper edges of the eardrum, and upper (epitympanum). The tympanic cavity has six walls. Lateral wall– membranous (paries membranaceus), formed by the tympanic membrane and the bone plate (lateral wall of the attic). Front wall- carotid (paries caroticus), present only in the lower half of the tympanic cavity, in the upper part there is an opening of the auditory (Eustachian) tube. This wall separates the tympanic cavity from the carotid canal, which contains the internal carotid artery. Bottom wall– jugular (paries jugularis), located 2-3 mm below the level of attachment of the tympanic membrane, under it is the bulb of the jugular vein. The tympanic nerve (branch of the IX pair), as well as the tympanic artery and vein, pass through this wall into the tympanic cavity. Back wall tympanic cavity - mastoid (paries mastoideus), on it there is a pyramidal eminence in which the stapedius muscle (m. stapedius) is located, outside of it is the opening of the channel of the tympanic string (branch of the VII pair), in the depth of the posterior wall lies the facial canal with the facial nerve , in the area of the epitympanic recess there is an entrance to the mastoid cave . Medial wall– labyrinthine (paries labirinthicus), has a bony protrusion with a diameter of about 8 mm – promontory (promontorium). The promontory is formed by the lateral wall of the cochlea's dome. On its surface there are grooves of the nerves of the tympanic (Jacobson's) plexus, carotid-tympanic nerves, in the area of the posteroinferior edge there is a window of the cochlea, closed by the secondary tympanic membrane, in the area of the anterior-inferior edge there is a window of the vestibule, closed by the base of the stapes. Anterior to it is the tendon of the tensor tympani muscle. . Top wall– tegmental (paries tegmen talis), is part of the bottom of the middle cranial fossa. In this part there are digestions (cracks), through which purulent processes can spread.
In the upper part of the tympanic cavity there are auditory ossicles (ossicula auditus): malleus (malleus), incus (incus), stirrup (stapes), which, thanks to ligaments and joints, form a movable chain between the tympanic membrane and the window of the vestibule. The malleus, located externally, has a head, a handle and two processes: a thin and long anterior process and a short lateral one. The lower end of the handle is fused with the eardrum. The incus is the middle link in the chain of auditory ossicles, consists of a body and two legs - short and long. The body of the incus and the head of the malleus connected to it are located in the supratympanic recess, or attic, located between the upper wall of the tympanic cavity and the tendon of the tensor tympani muscle. The short leg of the incus is connected by means of a ligament to the posterior wall of the tympanic cavity, and the long leg is articulated with the stirrup. The stapes consists of a head connected through a joint to the incus, anterior and posterior legs and a base. The legs and base limit the opening in which the stapes membrane is located. The base is fixed in the window of the vestibule by the annular ligament. The movements of the auditory ossicles are provided by the intraauricular muscles: the tensor tympani muscle and the stapedii muscle.
The walls of the tympanic cavity and the auditory ossicles are covered with a mucous membrane, which forms several folds and passes into the mucous membrane of the auditory tube and the cells of the mastoid process.
Anterior to the tympanic cavity is located auditory (Eustachian) tube (tuba auditiva) connecting it to the nasopharynx. The length of the pipe connecting the tympanic cavity with the nasopharynx is 34-45 mm. It has bone (1/3) and cartilaginous (2/3) parts. At the point of transition from one to another, the narrowest place (up to 1 mm) is noted - the isthmus. The pharyngeal opening of the auditory tube (ostium pharyngeum tubae auditivae) is located on the lateral wall of the pharynx at the level of the posterior end of the inferior turbinate. The tympanic opening (mouth) of the auditory tube (ostium tympanicum tubae auditivae) occupies the anterior - upper part of the carotid wall. In an adult, the tympanic opening is approximately 2 cm above the pharyngeal opening, as a result of which the Eustachian tube is directed downwards, inwardly and anteriorly towards the pharynx. The surface layer of the mucous membrane lining the wall of the auditory tube is represented by ciliated epithelium, which protects the middle ear from the penetration of infectious agents from the nasopharynx. The mucous membrane of the cartilaginous section contains a large number of mucous glands. At the moment of swallowing, the lumen of the tube opens, which ensures equalization of air pressure between the tympanic cavity and the external environment. The change in the lumen of the auditory tube is regulated by the work of the muscle that strains the palatine curtain (m. tensoris veli palatine), attached to the lateral wall of the tube and the tubopharyngeal muscle (m. salpingopharyngeus), which is attached to the lower wall in the area of the pharyngeal opening on one side and to the upper the horn of the thyroid cartilage on the other side, part of the fibers of this muscle is woven into the superior constrictor of the pharynx.
The bony part of the auditory tube is the lower hemicanal of the muscular tubal canal (canalis musculotubarius) of the temporal bone, and the upper hemicanal is occupied by the tensor tympani muscle. This muscle begins in the cartilaginous part of the auditory tube at the exit from the hemicanal into the tympanic cavity, the tendon m. tensoris tympani rotates around a small hook-shaped protrusion at the promontory of the cochlear process and attaches to the handle of the malleus.
System of cavities in the mastoid part of the temporal bone. The structure is individual, depending on age. These are accessory cavities of the tympanic cavity that perform a resonator function. The mastoid cave and cells (antrum et cellulae mastoideae) are lined with mucous membrane. The entrance to the cave from the tympanic cavity is located in the epitympanic recess in the area of the prominence of the lateral semicircular canal. The cave has an upper wall - a continuation of the roof of the tympanic cavity at the level of the temporal line, medial and posterior walls bordering the transverse sinus. The lower wall borders on other cells of the mastoid process. In fact, the mastoid cave is a continuation of the longitudinal axis of the epitympanic space and the lumen of the mouth of the auditory tube. Moreover, the anterior-lateral wall of the cave represents the posterior bony wall of the external auditory canal, the bottom of the cave is located at the level of the middle of the posterior bony wall of the external auditory canal. The largest cells are located under the cave in the mastoid process.
Innervation the middle ear is carried out mainly tympanic nerve (n. tympanicus – Jacobson nerve), which arises from the petrosal (inferior jugular) ganglion of the glossopharyngeal nerve. The sensitive portion of this nerve is formed by the peripheral processes of the pseudounipolar cells of this node. The central processes of these cells end on the interneurons of the nucleus of the solitary tract. The tympanic nerve contains preganglionic parasympathetic fibers, which are the axons of the cells of the inferior salivary nucleus. The tympanic nerve in the area of the petrosal fossa enters the canal of the same name, passes through it and penetrates the tympanic cavity through the lower aperture of the tympanic canaliculus (apertura inferior canaliculi tympani), the jugular wall. In the tympanic cavity, the nerve splits into the tympanic plexus (plexus tympanicus) - Jacobson's plexus. The plexus is located on the medial wall of the tympanic cavity. The nerves that form the plexus are located either in bone canals or in grooves. This plexus is joined by the sympathetic carotid-tympanic nerves (from the plexus of the internal carotid artery), passing into the cavity along the canals of the same name in the temporal bone. Postganglionic sympathetic fibers enter the tympanic cavity through the carotid-tympanic tubules and join the Jacobson plexus. The tympanic plexus also includes the connecting branch of the facial nerve (parasympathetic). As part of this plexus, the autonomic ganglia are designated, in which some of the preganglionic parasympathetic fibers are switched, and some pass in transit, forming the lesser petrosal nerve, leaving the tympanic cavity through the cleft of the lesser petrosal nerve. Thus, the mucous membrane of the tympanic cavity, the auditory tube to the isthmus, the mastoid cave and cells receive sensitive somatic innervation, secretory innervation, innervation of the vessels and nerves of the middle ear from the tympanic (Jacobson's) plexus.
The lesser petrosal nerve leaves the cranial cavity through the foramen lacerum, carrying with it sympathetic fibers from the internal carotid plexus. Preganglionic parasympathetic fibers are interrupted in the ear ganglion and postganglionic parasympathetic fibers as part of the auriculotemporal nerve (sensitive somatic) of the third branch of the trigeminal nerve approach the parotid salivary gland, providing its complete innervation. The connection between the innervation of the salivary gland and the tympanic cavity is the cause of increased salivation observed in diseases of the middle ear.
The sympathetic fibers of the carotid-tympanic nerves contain fibers from the nerve of the dilator pupillary muscle (from the superior cervical sympathetic ganglion). Therefore, their irritation on the side of the affected middle ear sometimes causes pupil dilation.
The tympanic chord (chorda tympani) transits through the tympanic cavity - this is a nerve that extends from the facial nerve in its lower section, formed by the peripheral processes of pseudounipolar cells of the geniculate ganglion and preganglionic parasympathetic fibers of the cells of the superior salivary nucleus. The tympanic string crosses the tympanic cavity, passing between the long process of the incus and the handle of the malleus. It leaves the tympanic cavity through an opening in the posterior wall, the temporal bone in its anterior section through the petrotympanic fissure (fissure petrotympanica) - Glaser's fissure, then continues its path to the lingual nerve of the third branch of the trigeminal nerve and to the autonomic submandibular node. At the node, preganglionic parasympathetic fibers switch and postganglionic fibers provide secretory innervation to the submandibular and sublingual salivary glands. Under conditions of pressure difference between the tympanic cavity and the external one, the tympanic membrane is retracted into the tympanic cavity, touches the tympanic chord, irritates it, thereby increasing salivation; the act of swallowing reflexively responds to excess saliva, during which the lumen of the cartilaginous part of the auditory tube expands (the tensor muscle contracts). velum palatine and tubopharyngeal muscle), the pressure is equalized.
Passes through the tympanic cavity in transit greater petrosal nerve (n. petrosus major). The nerve is formed by preganglionic parasympathetic fibers, which are the axons of the cells of the superior salivary and lacrimal nucleus. It branches off from the trunk of the facial nerve at the level of the first genu and then goes either in the bone canal of the upper wall of the tympanic cavity or freely. Leaves the cavity through the cleft of the canal of the greater petrosal nerve. Along the anterior surface of the pyramid of the temporal bone it is directed to the lacerated foramen, through which it leaves the cranial cavity. Having penetrated the outer base of the skull, it enters the pterygoid canal. In the canal it is joined by the sympathetic nerve from the internal carotid plexus - the deep petrosal nerve (n. petrosus profundus). The combined nerve is called the nerve of the pterygoid canal (n. canalis pterygoidei). Along the canal, the nerve penetrates into the pterygopalatine fossa, preganglionic parasympathetic fibers switch in the pterygopalatine node to postganglionic ones, and as part of the nodal branches of the maxillary nerve of the V pair, they and sympathetic postganglionic fibers reach the mucous glands of the oral cavity and nasal cavity according to the messages of the pterygopalatine fossa. The lacrimal gland is reached through the zygomatic nerve and the anastomosis between it and the lacrimal nerve. This “connection” helps explain the increased secretion of these glands during inflammatory processes in the middle ear.
Stapes nerve (n. stapedius), a thin stem, formed by the central processes of the cells of the motor nucleus of the facial nerve, branches off in the facial canal from the nerve in the area of the second knee, penetrates into the tympanic cavity, where it innervates the m. stapedius
The nerve of the muscle that strains the tympanic membrane (n. musculi tensoris tympani) and the nerve of the muscle that strains the veli palatine (n. musculi tensoris veli palatine) innervate the muscles of the same name. These are the motor branches of the mandibular nerve, V pair (trigeminal nerve). Tubalopharyngeus muscle (m. salpingopharyngeus) innervated by the motor branches of the vagus nerve, which are part of the pharyngeal plexus.
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The inner wall of the tympanic cavity is the most complex compared to other formations of the middle ear. It contains two openings - the window of the cochlea (fenestra cochleae) and the window of the vestibule (fenestra vestibuli), as well as a convexity - the promontory (promontorium (Fig. 4). The window of the vestibule is located behind and above the promontory, the window of the cochlea is behind and below the promontory. The window of the vestibule is closed by the base of the stapes, the window of the cochlea is covered by a fibrous membrane (secondary tympanic membrane).
Rice. 4. Schematic representation of the middle ear: 1 - roof of the tympanic cavity; 2 — entrance to the cave; 3 - protrusion of the lateral semicircular canal; 4 - bony canal of the facial nerve; 5 - window of the vestibule; 6 — cochlear window; 7 - jugular vein; 8 - eardrum; 9 - auditory tube; 10 - cape
Above the window of the vestibule there is a horizontal knee of the bony canal of the facial nerve, and above and behind there is the ampulla of the horizontal semicircular canal. The facial nerve goes around the projection of the horizontal semicircular canal from front to back, goes down, forming a descending knee, and through the stylomastoid foramen (foramen stylomastoideum) leaves the skull, dividing into a number of terminal branches - the so-called goose foot(pes anserinus). It is important for the otosurgeon to remember these anatomical formations, since their damage may be accompanied by the development of paresis or paralysis of the facial nerve and intralabyrinthine complications.
In the lower part of the tympanic cavity, the tympanic string (chorda tympani), which has taste and salivary fibers, emerges from the bone canal, separating from the facial canal. The fibers are located between the auditory ossicles (hammer and incus), pass through the entire tympanic cavity, heading to the tongue, submandibular and sublingual glands.
The external auditory canal and the middle ear are separated by the eardrum (membrana tympani), the thickness of which is about 0.1 mm, the shape is close to a circle, and the diameter is about 1 cm. On the outside, the eardrum is covered with epidermis, on the inside - with mucous membrane. Between the epidermis and the mucous membrane on the eardrum there is a connective tissue layer with radial and circular elastic fibers that provide tension to the eardrum. The eardrum is located obliquely in the external auditory canal, its upper part is deflected outward. The central part of the tympanic membrane is concave in depth, which is due to its fusion with the handle of the malleus. The area where the handle of the hammer ends is called the navel of the eardrum (umbo membranae tympani) and corresponds to the maximum retraction of the eardrum into the cavity of the middle ear.
The eardrum consists of two parts: tense (pars tensa) and relaxed (pars flaccida). The relaxed part is located in the upper part of the eardrum; it is small in size and lacks a fibrous layer; the stretched part is large and is located in the center and below. Due to the cone shape and unequal tension in different areas The eardrum has little intrinsic resonance and transmits acoustic signals of different frequencies with equal strength. The tympanic membrane is conventionally divided into four quadrants: anterosuperior, anterior-inferior, posterosuperior, posteroinferior (Fig. 5).
Rice. 5. Eardrum: 1 - posterosuperior quadrant; 2 - anterosuperior quadrant; 3 - posteroinferior quadrant; 4 - anterior inferior quadrant; 5 - lateral process of the malleus; 6 — light cone; 7— hammer handle
Quadrants are formed by two mutually perpendicular lines. This conventional division of the eardrum is adopted to indicate the location of scars, perforations and other pathological formations on its surface. The center of the tympanic membrane is located at a distance of 1.5-2 mm from the medial wall of the tympanic cavity; in the area of the anteroinferior quadrant it lags behind by 4-5 mm, in the area of the posteroinferior quadrant - up to 6 mm from the inner wall of the tympanic cavity.
As a result of this anatomical and topographical feature of the placement of the tympanic membrane, many clinicians, in case of inflammation of the middle ear, perform its paracentesis in the area most distant from the medial wall of the tympanic cavity - in the posteroinferior quadrant. The tympanic membrane, when illuminated by the frontal reflector, forms a reflection in the form of a light triangle in the anterior-inferior quadrant, called the light cone. The handle of the hammer and its short process are woven into the tympanic membrane along the radius.
The color of the eardrum in natural light is ash-gray, in electric light it is yellowish-gray. During otoscopy, the cone of light, the handle and the short process of the malleus can normally be seen. These landmarks are identifying marks of the eardrum. Subject to development pathological processes in the middle ear cavity, deformation or retraction of the eardrum, the light reflex may disappear, and the characteristics of other identifying marks also change.
In clinical practice, the tympanic cavity is conventionally divided into three floors: the upper - the supratympanic space, or attic (epitympanum), the middle (mesotympanum) and the lower (hypotympanum). The epitympanum is located above the short process of the malleus, the mesotympanum is located between the short process of the malleus and bottom wall external auditory canal (the level corresponds to the tense part of the eardrum), the hypotympanum is a small depression located below the level of attachment of the eardrum.
The tympanic cavity contains the auditory ossicles, ligaments, muscles, nerves and blood vessels. The auditory ossicles (Fig. 6) include: the malleus, the incus, and the stapes.
Rice. 6. Auditory ossicles: 1 - malleus; 2 - anvil; 3 - stirrup
The malleus is divided into a head, a neck, a lateral process and a handle. The hammer is tightly fixed with a handle to the eardrum, and its head is connected to the incus using a joint and tendon. The incus consists of a body, long and short legs, and a lenticular process. With its long process, the anvil is attached to the head of the stapes. The stirrup is the smallest bone in the human body. It distinguishes between a head, a neck, anterior and posterior legs and a base.
The base of the stapes is fixed in the window of the vestibule with the help of an annular ligament. The auditory ossicles are closely connected with the eardrum, the window of the vestibule, and also with each other, forming a single moving chain that transmits vibrations of the eardrum to the receptor structures of the inner ear.
There are also two miniature muscles located in the middle ear cavity - the tensor tympani muscle and the stapedius muscle. The tensor tympani muscle originates from the anterior wall of the tympanic cavity, where it inserts into the bony semicircular canal. Passing through the tympanic cavity, the muscle turns into a tendon and is woven into the handle of the malleus. Its innervation is carried out by fibers of the trigeminal nerve (V pair of cranial nerves).
Contraction of the tensor tympani muscle is accompanied by the movement of the hammer handle inward, which leads to pressing of the stapes into the oval window. The stapedius muscle originates from the posterior wall of the tympanic cavity and is attached to the head of the stapes. When it contracts, the base of the stapes moves out of the window of the vestibule into the tympanic cavity. The stapedius muscle is innervated by a branch of the facial nerve (VII pair).
The walls of the tympanic cavity and all its formations are lined with mucous membrane.
The middle ear cavity is connected to the environment through the auditory tube. The auditory tube is a narrow canal 30-38 mm long, which begins in the anterior wall of the tympanic cavity and ends with the tympanic opening in the cavity of the nasal pharynx at the level of the posterior end of the inferior turbinate. Anatomically, the bone and cartilaginous parts of the auditory tube are distinguished. The area of transition of one part to another is called the isthmus of the auditory tube (isthmus tubae auditivae).
This is the narrowest place of the auditory tube, and most often it is here that its blockage occurs. The lumen of the tube in the bone part is round, in the cartilaginous part it is slit-like. The muscle that strains the soft palate (tensor veli palatini) is attached to the cartilaginous part. From the place of its attachment the muscle goes down, turns into a tendon and ends at the aponeurosis soft palate. When swallowing and yawning, the muscle contracts, pulls back the cartilaginous part of the tube and opens the pharyngeal opening of the auditory tube.
Other muscles also take part in the expansion of the opening of the auditory tube - the muscle that lifts the velum palatini (the levator veli palatini) and the velopharyngeal muscle (the palatopharyngeus). Periodic opening of the auditory tube allows air to pass into the tympanic cavity and equalizes the pressure in it with the air pressure environment. The auditory tube is lined with mucous membrane. Its epithelium in the cartilaginous part is ciliated, multi-row, the movement of the cilia is directed towards the nasal part, which facilitates the evacuation of secretions from the tympanic cavity into the nasal part of the pharynx. In children, the auditory tube is located more horizontally, it is relatively wider and shorter, its pharyngeal opening gapes, which determines a more rapid spread of infection from the nasal cavity to the ear.
The mastoid process (processus mastoideus), located behind auricle, is a bone tissue containing air-filled cells. The shape of the process resembles a cone-shaped formation with its apex downwards. The mucous membrane lining the cave and the cells of the process is a continuation of the mucous membrane of the tympanic cavity. The cells are connected to each other, as well as to the tympanic cavity. The largest cell is called a cave (antrum mastoideum), it is round, the size of a pea. The child has this cell from birth.
The upper wall of the cave is a continuation of the roof of the tympanic cavity and separates the tympanic cavity and the cave from the middle cranial fossa. When the upper wall of the cave is destroyed purulent process inflammation from the middle ear can go directly to the membranes of the brain. On the inner surface of the mastoid process there is a depression in which the sigmoid venous sinus is located, which drains blood from the brain into the jugular vein.
DI. Zabolotny, Yu.V. Mitin, S.B. Bezshapochny, Yu.V. Deeva