Temporal bone, os temporale, a paired bone, complex in shape and structure, which participates in the formation of the base of the skull, being placed between the occipital and sphenoid bones, and also complements the lateral walls of the cranial roof. There are three parts located around the external auditory opening: scaly, tympanic and stony.
The scaly part, pars squamosa, is a vertically located bone plate. With a free, uneven, obliquely cut edge, it is connected through a scaly suture to the lower edge of the parietal bone and to the greater wing sphenoid bone. Below, the scaly part is adjacent to the petrous and tympanic parts and is separated from it by a petrosquamous fissure, fissura petrosquamosa (visible only on the bones of young subjects), and from the tympanic part by a tympanic-squamous fissure, fissura tympanosquamosa.
The outer temporal surface, facies temporalis, the scaly part is smooth, participates in the formation of the temporal fossa. Near the lower edge it extends zygomatic process, processus zygomaticus, directed anteriorly, where it connects with temporal process zygomatic bone and forms the zygomatic arch, arcus zygomaticus. The zygomatic process extends with two roots, between which the mandibular fossa, fossa mandibularis, is formed. It is covered with cartilage and articulates with the articular process lower jaw. The anterior root of the zygomatic process, thickening anterior to the mandibular fossa, forms the articular tubercle, tuberculum articulare. On the posterior root of the zygomatic process there is a similar retroarticular tubercle, tuberculum retroarticulare, less pronounced. Posteriorly it passes into the temporal line, linea temporalis.
The inner cerebral surface, facies cerebralis, of the scaly part is equipped with cerebral elevations, digital impressions, as well as grooves for the vessels of the meninges.
Figure: Temporal bone, right, external view.
1 - zygomatic process; 2 - articular tubercle; 3 - mandibular fossa; 4 - petrotympanic fissure; 5 - styloid process; 6 - drum part; 7 - external auditory opening; 8 - edge of the drum part; 9 - mastoid process; 10 - mastoid foramen; 11 - temporal line; 12 - scaly part.
The tympanic part, pars tympanica, is centered around the external auditory canal, meatus acusticus externus. In newborns, it is expressed in the form of a ring, anulus tympanicus, open upward and surrounding the external auditory canal. Subsequently, it grows and merges with neighboring parts. In adults, the tympanic part limits below and behind the external auditory opening, porus acusticus externus, and the tympanic cavity, cavum tympani, merging with the free edge with the scales and the mastoid part. It is separated from the scales by a tympanic-squamous fissure, into which a process of the tympanic roof enters from the front surface of the pyramid, due to which the said fissure is divided into two parallel fissures: the stony-squamous one, fissura petrosquamosa, and the stony-tympanic one, fissura petrotympanica, through which tympanic cavity goes through a branch facial nerve- drum string, chorda tympani. The cartilaginous part of the auditory canal is attached to the free rough and curved edge of the tympanic part, limiting the external auditory opening.
Above the external auditory opening rises the supra-ductal spine, spina supra meatum.
The petrous part, pars petrosa, or pyramid, is shaped like a three-sided pyramid, the base of which faces posteriorly and laterally, the apex facing anteriorly and medially. There are three surfaces on the pyramid, of which the anterior, facies anterior, and posterior, facies posterior, face the cranial cavity, and the lower, facies inferior, is part of the outer surface of the base of the skull. The surfaces are separated by three edges: top, back and front. The base of the pyramid is fused with the scaly part. A small portion of the base of the pyramid, facing outward, remains uncovered and contains the external auditory opening. The pyramid of the temporal bone contains most of the elements of the hearing organs: the bony part of the external auditory canal, the middle and inner ear.
On the anterior surface of the pyramid there is an arcuate eminence, eminentia arcuata, corresponding to the anterior semicircular canal of the labyrinth of the inner ear. In front of this elevation there are two thin grooves: the greater and lesser petrosal nerves, sulcin. retrosi majoris et n. petrosi minoris, ending in front with clefts of the same name, hiatus canalis n. petrosi majoris et hiatus canalis n. petrosi minoris. Nerves exit through these holes. The lateral part of this surface of the bone, lying between the arcuate eminence and the squamous-stony fissure, constitutes the upper wall of the tympanic cavity and is therefore called the tympanic roof, tegmen tympani. Near the apex of the pyramid there is a trigeminal impression, impressio trigemini. Along the upper edge of the pyramid there is a groove of the superior petrosal sinus, sulcus sinus petrosi superioris. On the posterior surface of the pyramid there is an internal auditory opening, porus acusticus internus, leading to the internal auditory canal, meatus acusticus internus. Posterior to the internal auditory opening is the external opening of the vestibular aqueduct, apertura externa aqueductus vestibuli, through which the ductus endolymphaticus passes. At the upper edge of the pyramid, between the internal auditory opening and the external opening of the aqueduct of the vestibule, there is a subarc fossa, fossa subarcuata, which in children reaches large sizes, and in adults it decreases significantly. At the lower edge at the level of porus acusticus internus there is an opening of the cochlear canaliculus, apertura externa canaliculi cochleae. Along the posterior edge of the pyramid there is a groove of the inferior petrosal sinus, sulcus sinus petrosi inferioris. The bottom surface of the pyramid is uneven. From it the styloid process descends down and forward, the processus styloideus - the place of muscle attachment. The process reaches its full development in older people. It is composed of several segments that ossify separately and merge with each other quite late. Between the styloid and mastoid processes, under the external auditory foramen, there is a stylomastoid foramen, foramen stylomastoideum, which serves as the exit point for the facial nerve. Anterior and medial to the styloid process is the jugular fossa, fossa jugularis. At the bottom of this fossa, the opening of the mastoid tubule, canaliculus mastoideus, is visible. Anterior to the jugular fossa is the external opening of the carotid artery canal, foramen caroticum externum, leading into the carotid artery canal, canalis caroticus, which opens at the apex of the pyramid with an internal exit opening, foramen caroticum internum. On the posterior wall of the carotid artery canal, near the external opening, there are several small openings of the carotid-tympanic tubules, canaliculi caroticotympanici, opening into the tympanic cavity and conducting vessels and nerves. In the ridge between the external opening of the carotid canal and the jugular fossa, a stony fossa, fossula petrosa, is identified, at the bottom of which the tympanic canaliculus for the nerve of the same name begins. Laterally from the foramen caroticum internum, in the depth of the angle formed by the scales and the anterior edge of the pyramid, the entrance opening of the muscular-tubal canal, canalis musculotubarius, is determined, divided by an incomplete bone septum into two half-canals: for the tensor muscle eardrum, semicanalis m. tensoris tympani, auditory tube, semicanalis tubae auditivae.
Figure: Right temporal bone, internal and posterior view.
1 - arcuate elevation; 2 - parietal edge; 3 - roof of the tympanic cavity; 4 - groove of the superior petrosal sinus; 5 - groove of the sigmoid sinus; 6 - mastoid foramen; 7 - occipital edge; 8 - styloid process; 9 - groove of the inferior petrosal sinus; 10 - top of the pyramid; 11 - rocky part, or pyramid; 12 - zygomatic process; 13 - wedge-shaped edge; 14 - arterial groove; 15 - rear surface of the pyramid; 16 - internal auditory opening.
The base of the pyramid is extended downward into the mastoid process, processus mastoideus, the outer surface of which is rough due to the attachment of the sternocleidomastoid muscle to it. Inside the mastoid process there are cells, cellulae mastoidei, various shapes and sizes lined with mucous membrane. The largest cell is the mastoid cave, antrum mastoideum, which communicates with the cavity of the middle ear. Inward from the apex of the mastoid process there are two parallel grooves. The groove of the occipital artery, sulcus a, runs medially. occipitalis, and laterally - the mastoid notch, incisura mastoidea, which is the origin of the digastric muscle. The mastoid process is separated from the tympanic part by the tympanomastoid fissure, fissura tympanomastoidea, through which the auricular branch of the vagus nerve passes. In the suture between the mastoid part and the occipital bone there is a mastoid foramen, foramen mastoideum. On the outer surface of the mastoid process, a practically important area is distinguished - the mastoid triangle, which is limited in front by a line drawn from the spina supra meatum (see the chapter “Temporal bone”) to the apex of the mastoid process, behind - by the line of attachment of the sternocleidomastoid muscle and above - a line that is a continuation of the lower edge of the zygomatic process. The triangle serves as a trepanation site for inflammatory processes middle ear.
On the inner surface of the mastoid process there is an S-shaped curved groove of the sigmoid sinus, sulcus sinus sigmoidei. Approximately halfway along its length, the mastoid opening opens.
Canals of the temporal bone. 1. The canal of the facial nerve, canalis facialis, begins at the bottom of the internal auditory canal and goes forward and laterally to the level of the clefts of the petrosal nerve canals. From here, at a right angle, it goes laterally and backwards, forming a bend - the geniculum canalis facialis, changes direction from horizontal to vertical and ends with the stylomastoid foramen.
2. Canal of the carotid artery, canalis caroticus (described in the text).
3. Musculotubal canal, canalis musculotubarius.
4. The canaliculus chordae tympani, starts from the facial canal slightly above the stylomastoid foramen and ends in the fissura petrotympanica region. A branch of the facial nerve passes through it - the chorda tympani.
5. The mastoid tubule, canaliculus mastoideus, originates at the bottom of the jugular fossa and ends in the tympanomastoid fissure. A branch of the vagus nerve passes through this canaliculus.
6. The tympanic canaliculus, canaliculus tympanicus, arises in the fossula petrosa with the opening apertura inferior canaliculi tympanici, through which the branch of the glossopharyngeal nerve enters, n. tympanicus. After passing through the tympanic cavity, this nerve called n. petrosus superficialis minor emerges through top hole channel located on the front surface of the pyramid.
Figure: Right temporal bone, ventral view.
1 - articular tubercle; 2 - mandibular fossa; 3 - petrotympanic fissure; 4 - drum part; 5 - mastoid process; 6 - mastoid notch; 7 - muscular-tubal canal; 8 - internal carotid foramen; 9 - external carotid foramen; 10 - jugular fossa; 11 - stylomastoid foramen; 12 - groove of the occipital artery.
7. Carotid-tympanic tubules, canaliculi caroticotympanici, pass in the wall of the carotid artery canal near its external opening and open into the tympanic cavity. They serve for the passage of blood vessels and nerves.
Ossification. The temporal bone has 6 ossification points. At the end of the 1st month of intrauterine development, ossification points appear in the scales, and at the 3rd month - in the tympanic part. At the 5th month, several points of ossification appear in the cartilaginous anlage of the pyramid. By the time of birth, the temporal bone consists of three parts: the squamous with the rudiment of the zygomatic process, the petrous with the rudiment of the mastoid part and the tympanic, which are basically already connected, but in the newborn there are still gaps between them filled with connective tissue. The styloid process develops from two centers. The upper center appears before birth and merges with rocky part during the 1st year of life. The lower center appears after birth and merges with the upper only after the onset of puberty. During the 1st year of life, the three parts of the bone fuse together.
Temporal bone(os temporale) is a container for the organs of balance and hearing. The temporal bone, connecting with the zygomatic bone, forms the zygomatic arch (arcus zygomaticus). The temporal bone consists of three parts: squamosal, tympanic and petrous.
Scaly part(pars squamosa) of the temporal bone has an outer smooth temporal surface (facies temporalis), on which runs the groove of the middle temporal artery (sulcus arteriae temporalis mediae). From this part (just above the external auditory canal) the zygomatic process (processus zygomaticus) begins, at the base of which there is the mandibular fossa (fossa mandibularis). In front, this fossa is limited by the articular tubercle (tuberculum articulare). On the inner cerebral surface (facies cerebralis) there are finger-like impressions and arterial grooves.
Drum part(pars tympanica) of the temporal bone is fused at its edges with the mastoid process and the scaly part, limiting the external auditory opening (porus acusticus externus) on three sides, the continuation of which is the external auditory canal (meatus acusticus externus). Posteriorly, at the site of fusion of the tympanic part with the mastoid process, a tympanomastoid fissure (fissura tympanomastoidea) is formed. In front of the auditory opening there is a tympanic-squamous fissure (fissura tympanosquamosa), which is divided by the edge of the roof of the tympanic cavity into a stony-squamous fissure (fissura petrosquamosa) and a stony-tympanic fissure (fissura petrotympanica).
Rocky part, or pyramid(pars petrosa), the temporal bone has the shape of a triangular pyramid. The pyramid is distinguished by the apex (apex partis petrosae), anterior, posterior and lower surfaces, upper and posterior edges and the mastoid process.
Canals of the temporal bone.
The anterior surface of the temporal bone on the lateral side passes into the medullary surface of the squamosal bone, from which it is separated by the petrosquamosal fissure (fissura petrosquamosa). Next to the stony-scaly fissure lies the opening of the muscular-tubal canal (canalis musculotubaris), which is divided by a septum into two semi-canals. One of them is the hemicanal of the auditory tube, and the other is the tensor tympani muscle.
In the middle of the anterior surface of the temporal bone there is an arcuate eminence (eminencia arcuata), between it and the petrosquamosal fissure there is the roof of the tympanic cavity (tegmen tympani). Near the apex of the anterior surface there is a trigeminal depression, lateral to which is the opening of the canal of the greater petrosal nerve (hiatus canalis nervi petrosi majoris), from which the groove of the same name begins. Lateral to this canal is the opening of the canal of the lesser petrosal nerve, from which the groove of the same name extends.
In the middle of the posterior surface of the pyramid of the temporal bone is the internal auditory opening (porus acusticus internus), which passes into the internal auditory canal. Lateral to this opening lies the subarcuate fossa (fossa subarcuata), below and lateral to which there is an external opening of the vestibular aqueduct (apertura externa aqueductus vestibuli).
The lower surface of the pyramid of the temporal bone has at its base a jugular fossa (fossa jugularis), on the anterior wall of which there is a groove ending in a mastoid foramen (foramen mastoideus). The posterior wall of the jugular fossa is represented by the notch of the same name. This notch and the notch of the occipital bone form the jugular foramen (foramen jugulare). In front of the jugular fossa, the carotid canal (canalis caroticus) begins, in the wall of which there are small pits that continue into the carotid-tympanic canaliculi. On the ridge separating the jugular fossa and the external opening of the carotid canal, there is a stony dimple (fossula petrosa), at the bottom of which the lower opening of the tympanic tubule opens. Lateral to the jugular fossa, the styloid process (processus styloideus) begins, posterior to which there is a stylomastoid foramen (foramen stylomastoideum).
The upper edge of the pyramid of the temporal bone separates the anterior surface from the posterior, and a groove of the superior petrosal sinus (sulcus sinus petrosi superioris) runs along its surface.
The posterior edge of the pyramid of the temporal bone separates the posterior and inferior surfaces; along it runs the groove of the inferior petrosal sinus (sulcus sinus petrosi inferioris).
The mastoid process (processus mastoideus) of the temporal bone is separated from the top from the scaly part by the parietal notch (incisura parietalis), and from below the process is limited by the mastoid notch (incisura mastoidea). Medial to the latter is the groove of the occipital artery (sulcus arteriae occipitalis). On the inner surface of the process there is a wide groove of the sigmoid sinus (sulcus sinus sigmoidei). The internal structure of the process is represented by cells, the largest of which is called the mastoid cave (antrum mastoideum).
Numerous canals and tubules pass through the temporal bone:
1) mastoid tubule (canaliculus mastoideus);
2) tympanic tubule (canaliculus tympanicus);
3) canaliculus chordae tympani;
4) carotid-tympanic tubules (canaliculus caroticotympanici);
5) carotid canal (canalis caroticus);
6) facial canal (canalis facialis);
7) muscular-tubal canal (canalis musculotubarius).
Temporal bone contains the organ of hearing and balance, serves as a support for the base of the skull and the masticatory apparatus. It consists of five parts - scaly, mastoid (mastoid). tympanic (tympanal), petrous part and styloid complex. The basis of the temporal bone is a pyramid, which has an apex directed towards the sphenoid bone, three sides and a base facing the mastoid process.
Upper inner face of the pyramid supports the middle cranial fossa. The cranial fossa itself is limited in front by the small wings of the main bone, in the back by the pyramid and partially by the back of the sella turcica. The main elements of the middle cranial fossa are the temporal lobes of the brain, the pituitary gland and the cavernous plexus.
Through a number of holes is carried out connection between the middle cranial fossa, the pyramid and the cellular spaces of the face and neck. One of these openings is the optic nerve canal, where the optic nerve and ophthalmic artery pass. Next, this is the superior orbital fissure, followed by the oculomotor, trochlear and abducens nerves, as well as the ophthalmic branch trigeminal nerve and ophthalmic veins. The maxillary branch of the trigeminal nerve passes through the foramen rotundum; through the foramen, the middle cranial fossa is connected to the pterygopalatine fossa. The carotid foramen contains the canal of the internal carotid artery and the sympathetic carotid plexus. Through this hole, communication is made with the cellular space of the neck.
In the oval hole The mandibular branch of the trigeminal nerve passes through the foramen; communication with the interpterygoid space is possible. Through the foramen spinosum, where the middle meningeal artery follows, there is a connection with the temporopterygoid space.
TO upper inner face of the pyramid The large nerves involved are: oculomotor, trochlear, trigeminal and abducens. On the upper part of the inner face of the pyramid, two anatomical elevations can be found. One eminence is formed by the gasserian ganglion (trigeminal ganglion), the other by the superior semicircular canal. There are two slits along the upper edge of the pyramid, in which the petrosal nerves are located.
Rear inner face of the pyramid creates support for the posterior cranial fossa. The posterior cranial fossa is formed in front by the pyramid of the temporal bone, and in the back by the cruciate eminence of the occipital bone. The main structures of the posterior cranial fossa are the cerebellum, pons and medulla oblongata.
Connection of the posterior cranial fossa with pyramid, as well as with the tissue of the face and neck, can be carried out through a series of holes.
Through foramen magnum(it contains: medulla oblongata, accessory nerve, vertebral artery And spinal nerve) there is communication with the spinal canal.
Through the jugular, opening (through it follow: the internal jugular vein, the posterior meningeal (meningeal) artery, glossopharyngeal, vagus and accessory nerves) anatomical contacts with the tissue of the neck are possible.
Through the hypoglossal nerve canal communication occurs with the fiber of the submandibular fossa. Through the emissaries of the mastoid veins, the posterior cranial fossa communicates with the veins of the diploe, the veins of the skull and the sigmoid sinus.
To the back of the pyramid The major cranial nerves are related: branch of the trigeminal nerve, facial nerve, vestibulocochlear nerve, glossopharyngeal, vagus. accessory, hypoglossal and intermediate nerves. Three sinuses run along the inner surface of the back face of the pyramid. The upper petrosal sinus runs along the upper edge of the posterior inner edge of the pyramid, and the lower petrosal sinus runs along the lower surface of the pyramid. They carry venous blood into the sigmoid sinus.
On the inner surface of the mastoid process there is a deep groove of the sigmoid sinus. The sigmoid sinus itself is located between the mastoid process and the cerebellum.
Transverse sinus drains into the superior limb of the sigmoid sinus. The lower knee of the sigmoid sinus turns anteriorly and inward and passes into the bulb of the internal jugular vein, located under the bottom of the tympanic cavity. The sigmoid sinus sends its blood to the internal jugular vein.
On rear inner face of the pyramid three main holes can be seen. This is the opening of the internal auditory canal (porus acusticus internus) with a diameter of 4-5 mm, behind it at a distance of 5-6 mm horizontally there is an opening of the external aperture of the vestibule aqueduct. Down from the opening of the internal auditory canal, at a distance of 5-6 mm, on the lower edge of the pyramid, the external aperture of the cochlear canaliculus opens (the aperture of the cochlear aqueduct).
Contents of the topic “Organ of hearing.”:1. Pyramid of the temporal bone. Elements of the pyramid of the temporal bone.
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(os temporale), steam room. There are three parts located around the external auditory opening: scaly, pyramidal (stony part) and tympanic (Fig. 1, 2).
The organs of hearing and balance are located in the temporal bone; blood vessels and nerves pass through its canals. It is involved in the formation of the temporomandibular joint.
Scaly part(pars squamosa) It is a vertically located plate, connected by its free edge with the lower edge of the parietal bone and with the large wing of the sphenoid bone. Below it is adjacent to the tympanic and petrosal parts and is separated from them tympani-squamous fissure (fissura tympanosquamosa) And stony-scaly fissure (fissura petrosquamosa)[visible only on bones of young subjects].
Outdoor, temporal surface (fades temporalis), the scaly part is smooth, participates in the formation of the temporal fossa. Below it is limited zygomatic process (processus zygomaticus), which is directed anteriorly, connects with the temporal process of the zygomatic bone, forming the zygomatic arch. At the base of the zygomatic process there is a root that forms articular tubercle (tuberculum articulare), and less pronounced retroarticular tubercle (tuberculum retroarticulare), passing into the temporal line. Between the articular and postarticular tubercles a mandibular fossa (fossa mandibularis). It is covered with cartilage and articulates with the condylar process of the mandible.
Rice. 1. Temporal bone, right:
a — topography of the temporal bone;
b — external view: 1 — scaly part; 2 - zygomatic process; 3 - articular tubercle; 4 - postarticular tubercle; 5 - mandibular fossa; 6— stony-scaly fissure; 7 — edge of the roof of the tympanic cavity; 8 - petrotympanic fissure; 9 - styloid process; 10 - drum part; 11 - mastoid process; 12— mastoid notch; 13 - external auditory canal; 14—mastoid foramen; 15—supraductal spine; 16 - temporal line; 17 - groove of the middle temporal artery;
c — anterior surface of the pyramid of the temporal bone: 1 — parietal edge; 2 - medullary surface of the scales; 3 - stony-scaly gap; 4 — roof of the tympanic cavity; 5 — arcuate elevation; 6 - groove of the sigmoid sinus; 7 - mastoid foramen; 8 - occipital edge; 9 - groove of the superior petrosal sinus; 10—upper edge of the pyramid; 11 - trigeminal depression; 12—carotid channel; 13 - rocky part; 14 — front surface of the pyramid; 15 - muscular-tubal canal; 16 - wedge-shaped edge; 17 - groove of the lesser petrosal nerve; 18 - groove of the greater petrosal nerve; 19 - cleft canal of the lesser petrosal nerve; 20 - cleft canal of the greater petrosal nerve;
d — view from the inside: 1 — scaly part; 2 - semicircular eminence; 3 — roof of the tympanic cavity; 4 - groove of the sigmoid sinus; 5 - mastoid foramen; 6 - aperture of the vestibular tubule; 7 - styloid process; 8 — aperture of the cochlear tubule; 9 - groove of the inferior petrosal sinus; 10 - internal auditory canal; 11 - groove of the superior sagittal sinus; 12 - zygomatic process;
d - bottom view: 1 - stony-scaly fissure; 2 - petrotympanic fissure; 3 — myotubal canal; 4 - internal aperture of the carotid canal; 5 - top of the pyramid; 6 - lower surface of the pyramid; 7 - groove of the inferior petrosal sinus; 8 - external aperture of the carotid canal; 9 - stony dimple; 10 - condylar tubule; 11 - jugular fossa; 12 - stylomastoid foramen; 13 - groove of the occipital artery; 14 - mastoid notch; 15 - mastoid process; 16 - styloid process; 17 - tympanic-squamosal fissure; 18 - mandibular fossa; 19 - articular tubercle; 20 - zygomatic process
Rice. 2. Cutting the temporal bone through the tympanic cavity:
1 - arcuate elevation; 2 - probe in the elbow of the facial nerve canal; 3 - groove of the greater petrosal nerve; 4 - hemicanal of the tensor tympani muscle; 5 - semi-canal of the auditory tube; 6 - probe in the carotid canal; 7 - probe in the stylomastoid foramen; 8 - mastoid cells; 9 - mastoid cave
Along the outer surface of the squamous part of the temporal bone runs groove of the middle temporal artery (sulcus a. temporalis mediae).
Internal, cerebral surface (fades cerebralis) has cerebral eminences, gyral depressions (finger-shaped); the grooves of the vessels of the meninges run along it.
Human anatomy S.S. Mikhailov, A.V. Chukbar, A.G. Tsybulkin
The temporal bone is divided into the pyramid (stony part) with the mastoid process, the tympanic part, and the scaly part.
Pyramid, or the rocky part is called so due to its hardness bone substance and has the shape of a triangular pyramid. Inside it is the organ of hearing and balance. The pyramid in the skull lies almost in a horizontal plane, its base is turned back and laterally and passes into the mastoid process.
Several channels of the temporal bone pass through the pyramid for cranial nerves and blood vessels.
Sleepy channel
The carotid canal (canalis caroticus) begins on the lower surface of the pyramid with the external carotid foramen, goes upward, bends almost at a right angle, then goes medially and forward. The canal ends with the internal carotid foramen at the top of the pyramid of the temporal bone. Through this canal the internal carotid artery and the nerves of the carotid plexus.
The internal carotid artery, the internal carotid (autonomic) nerve plexus, passes through the carotid canal.
Carotid tympanic tubules
Carotid-tympanic tubules (canaliculi caroticotympanici), numbering 2-3, begin on the wall of the carotid canal (near its external opening) and penetrate into the tympanic cavity.
These tubules contain the carotid-tympanic nerves and arteries.
Musculo-tubal canal
The muscular-tubal canal (canalis musculotubularis) has a common wall with the carotid canal, begins at the apex of the pyramid of the temporal bone, goes backward and laterally and opens into the tympanic cavity.
It consists of two sections: the semicanal of the auditory tube (semicanalis tubae auditivae) and the semicanal of the tensor tympani muscle (semicanalis m. tensoris tympani). The upper hemicanal is occupied by the tensor tympani muscle, and the lower one is the bony part of the auditory tube. Both half-channels open into the tympanic cavity on its anterior wall.
A horizontal partition divides it into two parts. Above is the hemicanal of the tensor tympani muscle (semicanalis musculi tensoris tympani), containing the muscle of the same name.
Below is the semicanal of the auditory tube (semicanalis tubae auditivae).
The tensor tympani muscle passes through the myotubal canal (the semi-canal of the tensor tympani muscle), auditory tube(half-canal of the auditory tube).
Facial canal
The canal of the facial nerve (canalis p. facialis) begins at the bottom of the internal auditory canal and goes forward and laterally to the level of the cleft of the canal of the greater petrosal nerve. Here a bend is formed - the knee of the facial canal (geniculum n. facialis). From the genu, the canal runs at a right angle laterally and backward along the axis of the pyramid, then changes horizontal direction to vertical and ends at the posterior wall of the tympanic cavity with the stylomastoid foramen.
The facial canal connects the posterior surface of the pyramid of the temporal bone (internal auditory canal) and the stylomastoid foramen (outer base of the skull).
The facial canal contains the facial nerve (VII pair of cranial nerves).
Drum string channel
The canaliculus chordae tympani starts from the facial nerve canal slightly above the stylomastoid foramen and ends in the petrotympanic fissure.
A branch of the facial nerve passes through it - the chorda tympani.
Tympanic canaliculus
The tympanic canaliculus (canaliculus tympanicus) is very narrow; begins in the depths of the stony dimple, goes upward, pierces the lower wall of the tympanic cavity and continues on the labyrinthine wall of this cavity on the surface of the promontory in the form of a groove. Then it pierces the septum of the muscular-tubal canal and ends with the cleft of the canal of the lesser petrosal nerve on the anterior surface of the pyramid.
The tympanic canaliculus contains the tympanic nerve, a branch of the 9th pair of cranial nerves.
Mastoid tubule
The mastoid canal (canaliculus mastoideus) originates in the jugular fossa, crosses the facial canal in its lower part and opens into the tympanomastoid fissure. The auricular branch of the vagus nerve passes through this canaliculus.
The auricular branch of the vagus nerve passes through this canaliculus.