The temporal bone is inside view. Temporal bone canals
The temporal bone, os temporale, is a steam room, a complex bone in shape and structure, which is involved in the formation of the base of the skull, located between the occipital and sphenoid bonesas well as complements the sidewalls of the skull roof. Three parts are distinguished in it, 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 connects through a scaly suture with the lower edge of the parietal bone and with the large wing of the sphenoid bone. At the bottom, the scaly part adjoins the stony and tympanic parts and is separated from it by a stony-scaly fissure, fissura petrosquamosa (visible only on the bones of young subjects), and from the tympanic part by a drum-scaly fissure, fissura tympanosquamosa.
The external temporal surface, facies temporalis, of the scaly part is smooth, participates in the formation of the temporal fossa. Near the lower edge, the zygomatic process, processus zygomaticus, departs from it, directed anteriorly, where it connects with the temporal process of the zygomatic bone and forms a zygomatic arch, arcus zygomaticus. The zygomatic process departs 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 an articular tubercle, tuberculum articulare. On the posterior root of the zygomatic process is a similar articular 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 eminences, digital impressions, as well as grooves of the vessels of the meninges.
Drawing: Temporal bone, right, outside view.
1 - zygomatic process; 2 - articular tubercle; 3 - mandibular fossa; 4 - stony-tympanic fissure; 5 - subulate process; 6 - drum part; 7 - external auditory opening; 8 - the edge of the drum part; 9 - mastoid process; 10 - mastoid opening; 11 - temporal line; 12 - scaly part.
The tympanic part, pars tympanica, is concentrated around the external auditory canal, meatus acusticus externus. In newborns, it is expressed in the form of a ring, anulus tympanicus, open upwards and surrounding the external auditory canal. In the future, it grows and merges with neighboring parts. In adults, the tympanic part limits from below and behind the external auditory opening, porus acusticus externus, and the tympanic cavity, cavum tympani, fused with the free edge with the scales and the mastoid part. It is separated from the scales by a drum-scaly slit, into which the process of the tympanic roof enters from the side of the front surface of the pyramid, due to which the named gap is divided into two parallel slits: stony-scaly, fissura petrosquamosa, and stony-tympanic, fissura petrotympanica, through which from the tympanic the cavity passes the branch facial nerve - drum string, chorda tympani. The cartilaginous part of the ear canal is attached to the free, rough and curved edge of the tympanic part, which limits the external auditory opening.
Above the external auditory opening rises the supraspin, spina supra meatum.
The stony part, pars petrosa, or pyramid, resembles a three-sided pyramid in shape, the base of which is turned posteriorly and laterally, the apex is anteriorly and medially. On the pyramid, three surfaces are distinguished, of which the front, facies anterior, and the back, facies posterior, face the cranial cavity, and the lower, facies inferior, is part of the outer surface of the skull base. The surfaces are separated by three edges: top, back and front. The base of the pyramid is spliced \u200b\u200bwith the scaly part. A small area of \u200b\u200bthe 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 front surface of the pyramid there is an arcuate eminence, eminentia arcuata, corresponding to the anterior semicircular canal of the labyrinth inner ear ... In front of this elevation are two thin furrows: the large and small stony nerves, sulci n. retrosi majoris et n. petrosi minoris, ending in the front with the same crevices, 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 scaly-stony gap, constitutes the upper wall of the tympanic cavity and is therefore called the tympanic roof, tegmen tympani. Near the top of the pyramid there is a trigeminal depression, impressio trigemini. A groove of the upper petrosal sinus, sulcus sinus petrosi superioris, runs along the upper edge of the pyramid. On the back surface of the pyramid there is an internal auditory opening, porus acusticus internus, leading to the internal auditory canal, meatus acusticus internus. Behind the internal auditory opening, the external opening of the aqueduct of the vestibule, 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 water supply system of the vestibule there is a subarc fossa, fossa subarcuata, which reaches large sizes in children, and decreases significantly in adults. At the lower edge, at the level of porus acusticus internus, there is an opening of the snail tubule, apertura externa canaliculi cochleae. Along the posterior edge of the pyramid there is a groove of the lower stony sinus, sulcus sinus petrosi inferioris. The lower surface of the pyramid is uneven. From it, the styloid process descends and forward, the processus styloideus is the place of muscle attachment. The process reaches its full development in the elderly. It is composed of several segments, ossifying separately and merging with each other rather late. Between the styloid and mastoid processes under the external auditory opening is the stylo-mastoid opening, the foramen stylomastoideum, which serves as the exit site of the facial nerve. In front and medially of the styloid process is the jugular fossa, fossa jugularis. At the bottom of this fossa, the opening of the mastoid canaliculus, canaliculus mastoideus, is visible. In front of the jugular fossa is the external opening of the carotid artery canal, foramen caroticum externum, leading to the carotid artery canal, canalis caroticus, which opens at the top of the pyramid with an internal outlet, foramen caroticum internum. On the posterior wall of the carotid canal near the external opening there are several small openings of the carotid tubules, canaliculi caroticotympanici, opening into the tympanic cavity and conducting vessels and nerves. In the crest between the external opening of the carotid canal and the jugular fossa, a petrous dimple, fossula petrosa, is distinguished, at the bottom of which the tympanic tubule begins for the nerve of the same name. Laterally from the foramen caroticum internum, in the depth of the angle formed by the scales and the anterior edge of the pyramid, the inlet of the musculocutaneous canal, canalis musculotubarius, is determined, divided by an incomplete bony septum into two semicanals: for the muscle straining the tympanic membrane, semicanalis m. tensoris tympani, auditory tube, semicanalis tubae auditivae.
Drawing: Right temporal bone, inside and back view.
1 - arcuate elevation; 2 - parietal margin; 3 - roof of the tympanic cavity; 4 - groove of the superior stony sinus; 5 - sigmoid sinus groove; 6 - mastoid opening; 7 - occipital margin; 8 - styloid process; 9 - furrow of the lower stony sinus; 10 - the top of the pyramid; 11 - rocky part, or pyramid; 12 - zygomatic process; 13 - wedge-shaped edge; 14 - arterial groove; 15 - the back 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 values \u200b\u200blined with mucous membranes. The largest cell is the mastoid cave, antrum mastoideum, which communicates with the middle ear cavity. Inside of the apex of the mastoid process there are two parallel grooves. The groove of the occipital artery, sulcus a, passes medially. occipitalis, and laterally - the mastoid notch, incisura mastoidea, which is the site of the beginning of the digastric muscle. From the tympanic part, the mastoid process is separated by a tympanic-mastoid fissure, fissura tympanomastoidea, through which the auricular branch of the vagus nerve passes. In the seam between the mastoid and the occipital bone there is a mastoid opening, foramen mastoideum. On the outer surface of the mastoid process, a practically important area is distinguished - the mastoid triangle, which is bounded 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 from 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. A mastoid opening opens approximately in the middle of its length.
Temporal bone canals. 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 canals of the petrous nerves. From here, at a right angle, it goes laterally and backward, forming a bend - a knee, geniculum canalis facialis, changes direction from horizontal to vertical and ends with an stylo-mastoid opening.
2. Canal of the carotid artery, canalis caroticus (described in the text).
3. Muscular-tubal canal, canalis musculotubarius.
4. The canaliculus of the drum string, canaliculus chordae tympani, starts from the facial canal slightly above the awl-mastoid opening and ends in the area of \u200b\u200bfissura petrotympanica. A branch of the facial nerve - the drum string - passes through it.
5. Mastoid tubule, canaliculus mastoideus, originates at the bottom of the jugular fossa and ends in the tympanic-mastoid fissure. A branch of the vagus nerve passes through this tubule.
6. The tympanic tubule, canaliculus tympanicus, arises in the fossula pеtrosa with the apertura inferior canaliculi tympanici opening through which the branch of the lingopharyngeal nerve enters, n. tympanicus. Having passed through the tympanic cavity, this nerve called n. petrosus superficialis minor exits through the upper opening of the canal, located on the front surface of the pyramid.
Drawing: Right temporal bone, bottom view.
1 - articular tubercle; 2 - mandibular fossa; 3 - stony-tympanic fissure; 4 - drum part; 5 - mastoid process; 6 - mastoid notch; 7 - muscular-tubal canal; 8 - internal sleepy opening; 9 - external carotid opening; 10 - jugular fossa; 11 - awl-mastoid opening; 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, 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: scaly with the rudiment of the zygomatic process, stony with the rudiment of the mastoid and the tympanic, which are mostly already connected, but the newborn still has gaps filled with connective tissue between them. The styloid process develops from two centers. The upper center appears before birth and merges with the stony part during the 1st year of life. The lower center appears after birth and merges with the upper center only after the onset of puberty. During the 1st year of life, three parts of the bone grow together.
Temporal bone(os temporale) is a receptacle for the organs of balance and hearing. The temporal bone, connecting with the zygomatic, forms a zygomatic arch (arcus zygomaticus). The temporal bone consists of three parts: scaly, tympanic and stony.
Scaly part(pars squamosa) of the temporal bone has an external smooth temporal surface (facies temporalis), on which the groove of the middle temporal artery (sulcus arteriae temporalis mediae) passes. From this part (just above the external auditory canal), the zygomatic process (processus zygomaticus) begins, at the base of which 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 with 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 meatus (meatus acusticus externus). Behind, at the place of fusion of the tympanic part with the mastoid process, a drum-mastoid fissure (fissura tympanomastoidea) is formed. In front of the auditory opening is a drum-scaly fissure (fissura tympanosquamosa), which is divided by the edge of the roof of the tympanic cavity into a stony-scaly (fissura petrosquamosa) and stony-tympanic fissure (fissura petrotympanica).
Rocky part, or pyramid(pars petrosa), the temporal bone has the shape of a triangular pyramid. In the pyramid, the apex (apex partis petrosae), the anterior, posterior and lower surfaces, the upper and posterior edges and the mastoid process are distinguished.
Temporal bone canals.
The anterior surface of the temporal bone from the lateral side passes into the medullary surface of the squamous bone, from which it is separated by a stony-squamous gap (fissura petrosquamosa). Near the stony-scaly fissure lies the opening of the musculocutaneous canal (canalis musculotubaris), which is divided by a septum into two half-channels. One of them is the semi-canal of the auditory tube, and the other is the muscle that strains the eardrum.
In the middle of the anterior surface of the temporal bone there is an arcuate eminence (eminencia arcuata), between it and the stony-scaly gap is the roof of the tympanic cavity (tegmen tympani). Near the apex of the anterior surface there is a trigeminal depression, lateral from which is the opening of the canal of the large stony nerve (hiatus canalis nervi petrosi majoris), from which the groove of the same name begins. Lateral to this canal is the opening of the small stony nerve canal, from which the groove of the same name departs.
In the middle of the posterior surface of the temporal bone pyramid is the internal auditory opening (porus acusticus internus), which passes into the internal auditory canal. Lateral to this hole lies a subarc fossa (fossa subarcuata), below and lateral to which there is an external opening of the aqueduct of the vestibule (apertura externa aqueductus vestibuli).
The lower surface of the pyramid of the temporal bone has a jugular fossa (fossa jugularis) at the base, on the front wall of which there is a groove ending in a mastoid opening (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 foramen jugulare. In front of the jugular fossa, the carotid canal (canalis caroticus) begins, in the wall of which there are small fossa continuing into the carotid-tympanic tubules. On the ridge separating the jugular fossa and the external opening of the carotid canal, there is a petrous 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, behind which there is a styloid opening (foramen stylomastoideum).
The upper edge of the temporal bone pyramid separates the anterior surface from the posterior one, and the groove of the superior stony sinus (sulcus sinus petrosi superioris) runs along its surface.
The posterior edge of the pyramid of the temporal bone separates the posterior and lower surfaces, along it there is a groove of the lower stony sinus (sulcus sinus petrosi inferioris).
The mastoid process (processus mastoideus) of the temporal bone from above is separated from the scaly part by the parietal notch (incisura parietalis), from below the process is bounded by the mastoid notch (incisura mastoidea). The groove of the occipital artery (sulcus arteriae occipitalis) is located medially to the latter. 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) the tympanic tubule (canaliculus tympanicus);
3) the tubule of the drum string (canaliculus chordae tympani);
4) carotid-tympanic tubules (canaliculus caroticotympanici);
5) sleepy canal (canalis caroticus);
6) the facial canal (canalis facialis);
7) muscular-tubal canal (canalis musculotubarius).
The temporal bone (os temporale) is a steam room, it contains the organs of hearing and balance. Nerves and blood vessels pass through its channels. The bone consists of three parts (Fig. 51).
The scales (squama) have the shape of an oval thin plate, located vertically, almost in the sagittal plane. The zygomatic process (processus zygomaticus) begins from the temporal surface of the scales. At the beginning of this process, on the lower surface of the scales, there is a mandibular fossa (fossa mandibularis), in front of which is an articular tubercle (tuberculum articulare). On the cerebral surface of the scales there are prints from the middle meningeal artery (a. Meningea media) and the convolutions of the temporal lobe of the brain.
51. The temporal bone is right.
A - inside view: 1 - eminentia arcuata; 2 - tegmen tympani; 3 - pars petrosa; 4 - sulcus sinus sigmoidei; 5 - apertura externa canaliculi cochleae; 6 - processus styloideus; 7 - apertura externa aqueductus vestibuli; 8 - porus acusticus internus; 9 - sulcus sinus petrosi superioris; 10 - processus zygomaticus.
B - bottom view: 1 - processus zygomaticus; 2 - fissura petrosquamosa; 3 - canalis musculotubarius; 4 - for. caroticum externtum; 5 - fossula petrosa; B - apertura externa canaliculi cochleae; 7 - fossa jugularis; 8 - sulcus arteriae occipitalis; 9 - incisura mastoidea; 10 - processus mastoideus; 11 - for. stylomastoideum; 12 - meatus acusticus externus; 13 - fossa mandibularis; 14 - tuberculum articulare.
The tympanic part (pars tympanica) has the shape of a semicircle, takes part in the construction of the front, lower and rear walls of the external auditory canal (meatus acusticus externus), the upper wall of which is limited by scales.
The stony part (pyramid) (pars petrosa) is triangular in shape, facing medially and anteriorly, has anterior, posterior and lower surfaces, anterior, upper and posterior edges.
On the front surface of the stony part, when it is connected to the scales, there is a platform - the roof of the tympanic cavity (tegmen tympani). In front, this platform is bounded by a gap (fissura petrosquamosa), laterally - by an arcuate eminence (eminentia arcuata). Under it are the anterior and posterior semicircular canals of the inner ear. From eminentia arcuata, closer to the apex of the pyramid, there are two openings representing the exit sites of the large and small stony nerves (hiatus canalis n. Petrosi majoris et minoris), opening into the grooves of the same name, which are oriented towards the apex of the pyramid.
On the posterior surface of the stony part there is an internal auditory opening (porus acusticus internus), where the facial and vestibular cochlear nerves pass. At the base of the stony part is a deep sigmoid groove (sulcus sigmoideus), where the opening of the mastoid venous outlet opens. Lateral to the internal auditory canal there is a slit-like opening of the aqueduct of the vestibule of the inner ear (apertura externa aqueductus vestibuli). On the upper edge, between the anterior and posterior surfaces of the stony part, there is a groove (siilcus sinus petrosi superioris), which reaches the sigmoid groove in the back, and the top of the pyramid in front.
On the lower surface of the base of the stony part, there is an styloid process (processus styloideus); behind it, the styloid opening (for. stylomastoideum) opens, representing the opening of the facial nerve canal. Medial to the styloid process, the jugular fossa (fossa jugularis) is visible, in which the posterior edge has the notch of the same name. The anterior edge of the jugular fossa is bordered by the external opening of the carotid canal (for.caroticum externum). In the front edge, there is a small stony fossa (fossula petrosa), at the bottom of which the tympanic canal (canaliculus tympanicus) begins. In adults, the mastoid process (processus mastoideus) is located behind the styloid foramen and the external auditory canal. In its thickness, there are cells lined with a mucous membrane and communicating with the tympanic cavity. The mastoid fissure and the occipital groove pass medially to the mastoid process. The latter contains the occipital artery. In the middle of the rear edge of the pyramid there is an external opening of the snail aqueduct (apertura externa canaliculi cochleae).
Temporal bone canals... The sleepy canal (canalis caroticus) begins on the lower surface of the pyramid with an external hole of the same name. The channel in the thickness of the pyramid turns at an angle of 90 ° and goes to the top of the pyramid, where it ends with an internal hole (for. Caroticum internum).
The facial canal (canalis facialis) begins in the internal auditory canal, then crosses across the pyramid and at the cleft of the large stony nerve (hiatus canalis n. Petrosi majoris) turns at a right angle to the side - the knee of the facial canal (geniculum canalis facialis), then goes laterally , located at the junction of the roof of the tympanic cavity with the labyrinthine wall of the inner ear. At the posterior wall of the tympanic cavity, the canal makes a turn and goes downward, ending on the lower surface of the temporal bone pyramid with the styloid opening.
The muscular-tubal canal (canalis musculotubarius) is limited by the anterior edge of the pyramid apex and scales. It consists of two sections: the semicanalis tubae auditivae and the semicanalis m. Tensoris tympani muscle stretching the eardrum.
The tympanic tubule (canaliculus tympanicus) is very narrow; begins in fossula petrosa and opens on the front surface of the stony part of the pyramid with a cleft of the canal of a small stony nerve (hiatus canalis n. petrosi minoris).
The canaliculus of the drum string (canaliculus chordae tympani) departs from the facial canal before exiting the stony part. It opens into the petrotympanic fissure of the mandibular fossa.
Ossification... The temporal bone of a newborn consists of three independent parts, which are described above. The external auditory meatus is relatively short and wide. The tympanic cavity is filled with loose connective tissue, which dissolves within the first 3 months after birth.
The tympanic part is presented in the form of an incomplete ring located under the scales laterally from the pyramid. In the lumen of the ring, the tympanic membrane is stretched. The ossification process occurs in the connective tissue ( primary bone), bypassing the cartilaginous stage. From the semicircle, scales and mastoid process, the external auditory meatus develops by the age of 6. At the 8th week of intrauterine development, three points of ossification appear in the fibrous connective tissue of the scales. From the back of the scales and the lateral part of the pyramid, under the action of the sternocleidomastoid muscle, the mastoid process is formed, which is pneumatized in three stages: up to 1 year, tympanic invagination is formed, cells are formed up to 3 years, pneumatization of the appendix completely ends up to 6 years. In the cartilaginous base of the pyramid at the 5th month of intrauterine development, 5 bone nuclei appear, which merge by the time of birth.
The temporal bone, the anatomy of which will be discussed later, is paired. It contains the organs of balance and hearing. The temporal bone of the skull takes part in the formation of its base and the lateral wall of the fornix. Articulating with the lower jaw, it is a support for the chewing apparatus. Next, let's take a closer look at what the temporal bone is.
Anatomy
There is an auditory opening on the outer surface of the element. There are three parts around it: scaly (above), stony (or pyramid of the temporal bone) - behind and inwards, tympanic - below and in front. The rocky area, in turn, has 3 surfaces and the same number of edges. The left and right temporal bones are the same. The segments contain channels and cavities.
Scaly part
It is presented in the form of a plate. The outer surface of this part is slightly rough and slightly convex. In the posterior section, the groove of the temporal (middle) artery runs in the vertical direction. An arched line runs along the posterior lower section. The zygomatic process departs from the scaly part somewhat anteriorly and from above in the horizontal direction. It seems to be a continuation of the ridge located on the outer surface along the lower edge. Its beginning is presented as a wide root. Then the process narrows. It has an outer and inner surface and 2 edges. One - the upper one is longer, and the second, the lower one, is, respectively, short. The front end of the element is serrated. The processes of the temporal bone in this area are connected with a suture. As a result, the zygomatic arch is formed. The mandibular fossa is located on the lower surface of the root. It has a transverse oval shape. The anterior part of the fossa - half to the stony-scaly fissure - is the articular surface of the temporomandibular joint. In front, the fossa is bounded by a tubercle. The outer plane of the scaly part takes part in the formation of the temporal fossa. At this point, muscle bundles originate. On the inner surface, there are finger-like impressions and an arterial groove. In the latter lies the meningeal (middle) artery.
The edges of the scaly part
There are two of them: parietal and wedge-shaped. The latter, serrated and wide, articulates with the scaly edge in the large wing of the sphenoid bone. As a result, a seam is formed. The superior posterior parietal margin is longer than the previous one, pointed and articulated with the scaly in the parietal bone.
Stony part
The structure of the temporal bone in this area is quite complex. The stony part includes the anteromedial and posterolateral sections. The latter is the mastoid process of the temporal bone. It is located posterior to the auditory (external) opening. It distinguishes between internal and external surfaces. The outer one is rough, has a convex shape. Muscles are attached to it. Downward, the process passes into a ledge. It has a conical shape and is quite well felt through the skin. There is a deep notch on the inside. Parallel to it and slightly posteriorly is the groove of the occipital artery. The posterior border of the process is the occipital serrated edge. When joined together, the edges in this area form a seam. In the middle of its length or at the occipital end, there is a mastoid opening. In some cases, there may be several of them. Here lie emissary mastoid veins. From above, the process is limited by the parietal margin. On the border with the eponymous section of the scaly part, it forms a notch. It includes an angle from the parietal bone and forms a suture.
Stony surfaces
There are three of them. The anterior surface is wide and smooth. It faces the cranial cavity, is directed obliquely in front and from top to bottom, passes into the cerebral plane of the scaly part. Almost in the center on the front surface there is an arcuate eminence. It is formed by the semicircular anterior canal of the labyrinth, which lies below. There is a roof of the drum part between the gap and the elevation. The posterior surface of the stony part, like the anterior, turns into the cranial cavity. However, it is directed backward and upward. The posterior surface is continued by the mastoid process. Almost in the middle of it is the auditory (internal) opening leading to the corresponding passage. The underside is uneven and rough. It forms part of the lower plane of the skull base. There is an oval or rounded jugular fossa. At its bottom, a small groove is noticeable leading to the opening of the mastoid canaliculus. The posterior edge of the fossa is delimited by the notch. It is divided into two parts by a small process.
The edges of a rocky area
There is a groove in the upper edge of the pyramid. It is an imprint of the venous sinus lying here and fixation of the tentorium of the cerebellum. The posterior edge of the rocky area separates the posterior and inferior surfaces. A groove of the stony sinus runs along the cerebral surface. Almost in the middle of the posterior margin, near the jugular notch, there is a funnel-shaped triangular depression. The anterior margin is shorter than the posterior and upper ones. It is separated from the scaly part by a slit. At the front edge is the opening leading to the tympanic cavity of the muscular-tubal canal.
Rocky part channels
There are several of them. The sleepy canal originates in the middle sections on the lower surface in the stony part with the outer opening. At first it points up. Further, bending, the canal follows medially and anteriorly, opening at the top of the pyramid with a hole. Carotid tubules are small branches. They lead to the tympanic cavity. At the bottom, in the internal auditory canal, the facial canal begins. It runs horizontally and almost at right angles to the axis of the stony section. Further, the channel is directed to the anterior surface. At this point, turning at an angle of 90 degrees, it forms a knee. Further, the canal passes to the posterior part of the medial wall in the tympanic cavity. Then, heading posteriorly, it runs along the axis in the rocky part to the elevation. From this place, it goes down vertically, opening with a styloid opening.
Drum string channel
It starts a few millimeters higher than the styloid foramen. The canal is directed up and forward, entering the tympanic cavity, opens on its posterior wall. The tympanic string - a branch of the intermediate nerve - passes through the tubule. It exits the cavity through the stony-tympanic fissure.
Muscular-tubal canal
It is a continuation of the anterior superior region of the tympanic cavity. Its outer opening is located near the notch between the scaly and stony parts of the bone. The canal runs laterally and somewhat posterior to the horizontal section of the carotid tract, practically along the longitudinal axis of the stony section. There is a partition inside it. It is horizontal. This partition divides the canal into two parts. The upper one is the semicanal of the muscle, which strains the eardrum. The large lower section refers to the auditory tube.
Tympanic tubule
It starts from the lower surface in the pyramidal part, deep in the stony fossa. Further, it is directed towards the lower cavity, piercing which, it passes along the medial wall, reaching the groove of the cape. Then he goes to the top plane. There it opens with a cleft in the stony nerve canal.
Drum part
This is the smallest section that includes the temporal bone of the skull. It is presented in the form of a somewhat curved annular plate. The tympanic part forms part of the posterior, inferior and anterior walls of the auditory (external canal). A border gap is also visible here, which, together with the stony one, delimits this area from the mandibular fossa. The outer edge is closed from above by bone scales. It delimits the auditory (external) opening. A spine is present at its posterior upper outer edge. There is a dimple underneath it.
Damage
One of the most serious injuries is a temporal bone fracture. It can be both longitudinal and transverse. Both types of damage, in contrast to injuries to other bones, are characterized by the absence of movement of fragments. As a result, the slit width is generally small. An exception is impression damage to the scales. In such cases, there may be a significant displacement of the fragments.
CT of the temporal bones
The study is used when there are suspicions of violations in the structure of the element. Computer diagnostics is a special method. With its help, the temporal bone is scanned in layers. This creates a series of images. The temporal bone is examined in cases of the presence of:
- Injuries on one or both sides.
- Otitis media, especially of unknown nature.
- Disorders of balance and hearing, signs of dysfunction of the formations, next to which the temporal bone is located.
- Otosclerosis.
- Suspicion of a tumor in structures located near or within the temporal bone.
- Mastoiditis.
- Brain abscess in the vicinity of the bone.
- Discharge from the ear.
Tomography of the temporal bones is also indicated in preparation for electrode implantation.
Contraindications to the study
Computed tomography allows specialists to obtain accurate information about the condition of the temporal bones and is considered one of the best diagnostic methods for various disorders. Nevertheless, in some cases it is necessary to refuse to carry out this procedure. This is due to the presence of contraindications in patients. Among them it should be noted:
- All stages of pregnancy. Exposure to ionizing radiation generated by the tubes of the apparatus can provoke the development of fetal pathology.
- Overweight. Structurally, the tomograph is not intended for examining obese patients.
- Hypersensitivity to contrast agent. When a compound is introduced into the body, a severe allergic reaction can develop, up to anaphylactic shock.
- Renal failure In patients in this case, the contrast agent is not excreted from the body, which can be harmful to health.
There are other limitations to diagnostics. They are rare enough.
| Temporal bone, (os temporale). Outside surface. Right view. 1-scaly part (scales) of the temporal bone; |
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Temporal bone (os temporale). Inner surface. 1-scaly part of the temporal bone; |
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Temporal bone (os temporale). Cut through the tympanic cavity along the long axis of the pyramid (right bone). 1-scales of the temporal bone |
The temporal bone, os temporale, steam room, is very complex in structure, since the organs of hearing and balance are enclosed in its thickness, and, in addition, the bone is pierced by a number of channels through which vessels and nerves pass. The temporal bone is located in the lateral parts of the skull between the occipital, parietal and sphenoid bones, supplementing with one part the cranial vault, the other with the base of the skull. The temporal bone is connected to the facial skull: with the help of a joint - with the lower jaw, and a suture - with the zygomatic bone.
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The temporal bone is composed of several fused parts. When examining the temporal bone from the side of the outer, temporal surface, at its lower edge, there is a large opening, which is called the external auditory opening, porus acusticus externus. The opening is surrounded by four component parts of the temporal bone: above and in front - flat, with a pointed edge, scales of the temporal bone, squama temporalis, in front and below - small, in the form of a groove, plate - tympanic part, pars tympanica, behind - a powerful bony protrusion - mastoid part , pars mastoidea, from the inside - in the form of a pyramid, tapering in the direction from the mastoid part obliquely inward and anteriorly - a stony part or pyramid, pars petrosa s. pyramis. The scales of the temporal bone, squama temporalis, has the form of a semicircular bone plate, facing its smooth temporal surface, fades temporalis, outward and the inner, cerebral surface, fades cerebralis, into the cranial cavity. The semicircular-shaped edge bounding the scales is not the same everywhere; the anterior and posterior portions of the edge are more serrated and less sharpened from the inside than the upper portion. The anterior edge is connected to the scaly edge of the large wing of the main bone and is called the main edge, margo sphenoidalis; the upper posterior edge, connecting with the scaly edge of the parietal bone, is called the parietal edge, margo parietalis. The posterior-lower part of the scales passes into the mastoid part.
In children, at the junction of these parts, there is an obliquely directed scaly-mastoid suture, sutura squamomastoidea, directed from top to bottom and anteriorly. Remnants of this suture are sometimes preserved in adults. Slightly higher and along it is the temporal line, the front end of which comes to the root of the zygomatic process of the temporal bone, processus zygomaticus ossis temporalis. The zygomatic process departs with two roots: posterior and anterior. It runs horizontally, first outward and then at an angle anteriorly, and ends with a serrated end. The latter, it connects with the temporal process of the zygomatic bone, forming with it a zygomatic arch, arcus zygomaticus. Below the zygomatic process and in front of the external auditory foramen, is the glenoid fossa of the lower jaw, fossa mandibularis. In the anterior sections, the fossa is limited by a well-visible articular tubercle, tuberculum articulare; in the back - smaller, behind - the articular process, processus retroarticularis. The anterior part of the fossa and the articular tubercle are covered with cartilage. In the posterior part of the outer surface, fades temporalis, the scales of the temporal bone carry the groove of the middle temporal artery, sulcus arteriae temporalis mediae. This furrow rises upward and branches in the upper segment of the scales.
Brain surface, fades cerebralis, the bones are somewhat concave, has a well-defined, deep arterial groove in the anterior section, sulcus arteriosus (meningeus) (the place of adhesion of the meningeal artery of the brain), traces of depression of the brain convolutions - digital impressions, impressiones digitatae, and between the latter protrusions - cerebral eminences , juga cerebralia. Rocky part or pyramid, parspetrosa s. pyramis, has the appearance of a three-sided pyramid in a supine position, so that its base, basis pyramidis, is directed outward and connects with the mastoid and scaly parts of the temporal bone. At the place where the base of the pyramid adjoins the scaly part in childhood there is a gap, flssura petrosquamosa, over the years it fills bone tissue, and thus the border between these two parts disappears.
The top of the pyramid has an uneven edge. It is directed forward and inward, towards the lateral surface of the bodies of the sphenoid and occipital bones. The gap remaining between them on the whole skull is called torn hole, foramen lacerum (Fig. 124), filled with fibrous cartilage, fibrocartilago basilaris. In the region of the apex, the internal opening of the carotid artery canal, foramen caroticum intemum, opens large. The upper corner of the pyramid, angulus superior pyramidis, protrudes freely into the cranial cavity at the border of the anterior and posterior surfaces of the pyramid, fades anterior and fades posterior pyramidis. The upper stony groove, sulcus petrosus superior, runs along the upper corner of the pyramid, a trace of the venous sinus of the same name. The anterior corner of the pyramid, angulus anterior pyramidis, is located on the border of the anterior and lower surfaces of the pyramid, facies anterior and facies inferior pyramidis. With an internal segment, the anterior angle is connected to the edge of the large wing of the main bone with the help of cartilage, forming a basal-stony synchondrosis, synchondrosis sphenopetrosa. The outer segment of the anterior angle connects with the scales of the temporal bone, forming a stony-scaly slit, fissura petrosquamosa.
Near the medial end of the stony-scaly fissure, in the corner where the anterior corner of the pyramid converges with the anterior edge of the scales, one can see tubal opening, canalis musculotubarius. The latter, located obliquely outward and backward, is divided by a horizontally standing thin bone plate - the septum of the muscular-tubal canal, septum canalis musculotubarii, into two parts: the upper - the semicanal of the muscle straining the tympanic membrane, semicanalis musculi tensoris tympani, and the lower - the semicanal of the auditory ) pipes, semicanalis tubae auditivae Eustachii. Both half-channels lead to the middle ear cavity. The posterior angle of the pyramid, angulus posterior pyramidis, is located on the border of its posterior and lower surfaces, facies posterior et facies inferior pyramidis. It adjoins the lateral edges of the partes basilaris and lateralis ossis occipitalis. The inner part of the posterior angle is adjacent to the pars basilaris ossis occipitalis, and here a stony-occipital fissure, fissura petrooccipitalis, is formed, made by cartilage connecting both bones, - synchondrosis petrooccipitalis. On the cerebral surface of this part of the posterior angle, the lower stony groove, sulcus petrosus inferior, passes. The latter, connecting with the groove of the same name on the adjacent part of the occipital bone, is the site of the temporal sinus (sinus petrosus inferior).
At the outer end of the groove, at the posterior corner of the pyramid, there is a small depression, at the bottom of which a small external opening of the cochlear canal opens, apertura externa canaliculi cochleae. (Here v. Canaliculi cochleae and ductus perilymphaticus pass from the inner ear cavity). The lateral part of the posterior corner of the pyramid is adjacent to the pars lateralis ossis occipitalis. There is a small jugular notch, incisurajugularis, which corresponds to the notch of the same name on the occipital bone and together with it on the whole skull forms a jugular foramen, foramen jugulare.
At these three corners of the pyramid, three of its surfaces converge: front, back and bottom. The first two are directed into the cranial cavity, the latter directed towards the outer surface of the skull base. The anterior surface of the pyramid, fades anterior pyramidis, is uneven, located obliquely anteriorly. Outside, it borders on scales, forming a stony-scaly crack, fissura petrosquamosa; from the inside, it borders on the body of the main bone, without reaching it and forming here with the uneven edge of its apex the ragged hole described above, foramen lacerum. The anterior-lower and posterior-upper boundaries are the corresponding corners or edges of the pyramid. On the front surface of the pyramid, near the apex, there is an impression trigeminal nerve, impressio nervi trigemini, - an imprint of the adjacent Gasser's node of the trigeminal nerve (ganglion Gasseri).
A semicircular elevation, eminentia arcuata, is the relief of the upper semicircular canal slightly to the side of the middle of the anterior surface of the pyramid. The area of \u200b\u200bthe anterior surface, located between the elevation and the stony-scaly fissure (fissura etrosquamosa), is the roof of the tympanic cavity, legmen tympani; which is a thin plate that forms the upper wall of the middle ear cavity. Tegmen tympani with its front edge enters the gap between pars tympanica from behind and pars squamosa in front, forming a ridge visible in the fossa mandibularis area, called processus inferior tegmenis tympani (s. Crista tegmcntalis) (see more about this in the description of pars tympanica).
A little inward and downward from eminentia arcuata, two holes are visible. One of them is located more medially and is the opening of the facial nerve canal, hiatus canalis facialis. Through this opening, a branch of the facial nerve emerges - a large stony nerve, nervus petrosus superficialis major, which lies in the corresponding groove - sulcus nervi petrosi superficialis majoris, which runs longitudinally inward and anterior to hiatus canalis facialis.
Another opening is located lateral and is the superior opening of the tympanic tubule, apertura superior canaliculi tympanici. Through this hole, a small stony nerve emerges - nervus petrosus superficialis minor, which lies in the groove of the same name - sulcus nervi petrosi superficialis minoris. This groove, heading inward and anterior to the pyramid, runs parallel and outward from the sulcus nervi petrosi superficialis majoris. The posterior surface of the pyramid, fades anterior pyramidis, is located more vertically than the anterior one, however, having some slope posteriorly and downward. Inwardly from the upper corner, closer to the middle of the posterior surface, there is a rather wide internal auditory opening, porus acusticus internus. It opens into a channel leading into the rocky part. This channel is called internal auditory canal, meatus acusticus interims. (For its further course inside the rocky part, see "Ear".)
Outside and posteriorly from porus acusticus internus, a small slit-shaped opening is visible, called external opening of the water supply-vestibule, apertura externa aquaeductus vestibuli, which is the exit site of the internal lymphatic duct, ductus endolymphaticus, from the inner ear cavity. Slightly above the water supply hole, at the upper corner of the pyramid, is sub-semicircular fossa, fossa subarcuata, clearly visible in young people. The lower surface of the pyramid, fades inferior pyramidis, is directed downward and facing the outer surface of the base of the skull; outside and slightly in front, this surface is in contact with the tympanic part of the temporal bone. It carries a large number of holes, indentations and protrusions.
The central place on the lower surface of the pyramid is occupied by a large round opening, which is the entrance to the carotid canal, the external opening of the carotid canal, foramen caroticum externum. (The internal carotid artery and the nerve plexus enter through this hole.) Behind and outside of the foramen caroticum externum, separated from it by a crest, there is a wide jugular fossa, fossa jugularis, reaching the posterior edge of the lower surface of the stony part, where there is a jugular notch, incisura jugularis. It contains the bulb of the jugular vein. At the bottom of the jugular fossa, closer to its front edge, there is a groove of the mastoid canaliculus, sulcus canaliculi mastoidei, ending with the opening of the mastoid canaliculus, canaliculus mastoideus.
On the crest separating the fossa jugularis from the foramen caroticum externum, there is a barely noticeable stony dimple, fossula petrosa, leading to the lower opening of the tympanic tubule, apertura inferior canaliculi tympanici. (Here pass a.tympanica inferior and n. Tympanicus - from a stony node.) At the very base of the pyramid, on the outer part of the lower surface, a styloid process, processus styloideus, which is semicircular in front of the bony sheath, vagina processus styloidei, formed by the tympanic part of the temporal bone.
Near the styloid process, on the border with the mastoid process, processus mastoideus, is the styloid foramen, foramen stylomastoideum, the exit point of the facial nerve and blood vessels. In the pyramid of the temporal bone there are a number of channels through which the vessels and nerves pass, and the organ of hearing and the organ of balance of the body are laid that's why the pyramid has such a complex structure. All these formations are visible on special preparations of cuts of the temporal bone, carried out in different directions.
1. Formations related to the structure of the organs of hearing and balance:
and). external auditory opening, porus acusticus externus, and its continuation into the external auditory canal, meatus acusticus externus, are the bony parts of the external ear;
b). tympanic lining, tegmen tympani, is top wall the middle ear cavity, where the canalis musculo-tubarius opens, lying on the outer edge of the anterior corner of the pyramid;
in). inner ear cavity(labyrinth) is indicated on the front surface of the pyramid by a semicircular elevation, eminentia arcuata, where the upper semicircular canal fits, and on the posterior surface - by a fossa, fossa subarcuata.
Small holes on the back of the pyramid, apertura externa canaliculi cochleae and apertura externa aquaeductus vestibuli, lead to the inner ear; they contain vessels and lymphatic ducts through the porus acusticus internus passing through the auditory and facial nerves.
2. Facial nerve canal (fallopian canal), canalis facialis (Falloppii), inside the stony part of the temporal bone. It begins with the opening of the bottom of the internal auditory canal, in the area of \u200b\u200bits upper recess - the area facialis (see "Ear"), and continues the direction of the internal auditory canal forward and outward under the anterior surface of the stony part. Here, to the front surface of the pyramid, a branch departs from it, ending in a hole - hiatus canalis facialis; the canal itself, turning outward and backward, forms the knee of the auditory nerve canal, geniculum canalis facialis, at the place of rotation.
After the formation of the knee, the canal follows posteriorly and somewhat downward and, reaching the posterior part of the inner wall, cavum tympani, passes into the vertical part. Further, it goes down and opens behind the base of the styloid and anterior to the mastoid processes - the styloid opening, foramen stylomastoideum. The upper end of the vertical part of the canal forms the protrusion of the facial nerve canal, prominentia canalis facialis, located in the posterior part of the medial wall of the inner ear. Slightly lower, the canal of the facial nerve gives a branch of the canadian drum string, canaliculus chordae tympani, through which the nerve passes - the drum string, chorda tympani, and which ends in fissura petrotympanica (Glaseri).
3. Tympanic tubule, canaliculus tympanicus, skips the branch of the lingopharyngeal nerve. The canaliculus begins with the lower opening of the tympanic tubule at the bottom of the petrous fossa, fossula petrosa (from the side of the lower surface of the stony part), and, going arcuate posteriorly, upward and then forward, opens with the upper opening of the tympanic canaliculus, apertura superior canaliculi tympanici (on the anterior surface of the petrous part) ... Canaliculus tympanicus communicates with canalis nervi facialis Falloppii in the area of \u200b\u200bhis knee. 4. The canal of the carotid artery, canalis caroticus, is short, wide and curved. The internal carotid artery and its venous and nerve plexus pass through it. The canal begins with a hole located on the lower surface of the pyramid - foramen caroticum externum.
Further, the canal rises upward, then forms a bend almost at a right angle and, going horizontally anteriorly and inside, opens with the internal opening of the carotid canal, foramen caroticum internum. Near the external opening, in the wall of the carotid canal, small openings of the carotid canaliculi open, canaliculi curaticotympanici. These canals are short, go to the anterior wall of the cavum tympani, bypassing the wall of the carotid canal from above. Opening in the anterior wall of the cavum tympani, they pass the branches of the internal carotid artery and the superior and inferior carotid tympanic nerves.
Mastoid part,pars mastoidea, located posterior to the external auditory canal. Outside, it smoothly turns into scales, and from the inside - into a rocky part. Downward, the mastoid part faces a free convex surface, posteriorly and outwardly - a rough surface. The posterior, occipital edge, margo occipitalis, connects to the mastoid edge of the occipital bone, forming the occipital-mastoid suture, sutura occipitomastoidea.
Top edge, together with the posterior part of the parietal edge of the scales, forms the parietal notch, incisura parietalis. This notch is performed by the mastoid angle of the parietal bone, angulus mastoideus, connecting to the mastoid part with the help of the mastoid-parietal suture, suturaparietomastoidea. In front, in the upper part, the mastoid part passes into scales, in the lower part it borders on the tympanic part, forming a tympanic-mastoid fissure with it, fissura tympanomastoidea. In the anterior section, which constitutes the upper-posterior part of the edge of the external auditory foramen, there is a small protrusion - the access spine, spina suprameatum, and near it posteriorly - the mastoid fossa, fossa mastoidea.
The rough antero-lower part of the outer surface and ends with a blunt and powerful mastoid process, processus mastoideus, which is directed obliquely anteriorly and downward and is easily felt through the skin, in adults it varies, the degree of its development in children of the first years of life is poorly expressed (Fig. 83 ). In the posterior-lower part of the outer surface of the process there is a mastoid opening, foramen mastoideum, belonging to the group of graduation openings, emissaria Santorini; it penetrates through the entire thickness of the bone and opens on the inner surface of the mastoid process. This hole is not constant in size and position: sometimes it is one and is located in the area of \u200b\u200bsutura squamomastoidea, sometimes there are several of them.
From the outside and from below, the mastoid process carries a deep mastoid notch, incisura mastoidea, - the place where the digastric muscle (m. Digastricus) begins. Medial and parallel to the notch passes the groove of the occipital artery, sulcus arteriaeoccipitalis. On the inner, cerebral, surface of the mastoid, there is an S-shaped groove, sulcus sigmoideus, - the place of occurrence of the venous sinus of the same name - sinus sigmoideus. Very often, the inlet of the above-mentioned foramen mastoideum opens into the same groove. Processus mastoideus belongs to the group of pneumatic bones. As can be seen from the drawings depicting the cut of the mastoid process, it has a large number of interconnected cells, cellulae mastoideae, lined with a mucous membrane. The cells are filled with air coming in from the middle ear cavity. In the anteroposterior corner, inside the mastoid process, there is a large cell called the tympanic cavity, antrum tympanicum, which communicates, on the one hand, with the middle ear cavity, and on the other, with the mastoid cells.
The number and size of cells can be different for different individuals. The tympanic part, pars tympanica, is laid during the period of embryonic development in the form of a horseshoe-shaped half-ring - a tympanic ring, annuhis tympanicus, which forms the lower periphery of the external auditory canal. The ends of the semicircle: the anterior, large tympanic spine, spina tympanica major, and the posterior, minor tympanic spine, spina tympanica minor, limit the gap, called the tympanic notch, incisura tympanica (Rivini), above which (above both spines) hangs the lower edge of the scaly part of the temporal bones, thus closing the semicircle from above. The tympanic groove, sulcus tympanicus, is the site of attachment of the tympanic membrane along the circumference of the inner surface of the ring.
On the inner surface of spina tympanica major there is an obliquely passing spinous scallop, crista spinarum, the sharp ends of which are called: anterior - processus tympanicus anterior, and posterior - processus tympanicus posterior. A sulcus mallei runs along the crest and below it. Due to the growth of bone substance from the outer surface of the semicircle, the latter takes the form of a grooved plate, which on the temporal bone of an adult forms the anterior, lower and part of the posterior wall of the external auditory opening, porus acusticus externus, and the external auditory meatus, meatus acusticus externus. With the lengthening of the bone groove of the tympanic part, the external auditory canal also lengthens with age: thus, the tympanic membrane, which lies more superficially in children, due to this, goes into depth.
The upper front edge of the tympanic part is separated from the scaly part over a large extent by the anterior edge of the stony part wedging between them - the lower process of the roof of the tympanic cavity, processus inferior tegmenis tympani (s. Crista tegmentalis). Between this process in front and pars tympanica behind, a stony-tympanic gap, fissura petrotympanica (Glaseri), is formed, through which small vessels and a nerve pass - a drum string, chorda tympani. Between the process at the back and the pars squamosa in front, another gap is formed - stony-scaly, fissura petrosquamosa, made by connective tissue.
The posterior lower edge of the tympanic part borders on the mastoid part of the temporal bone, forming at the point of contact a tympanic-mastoid fissure, fissura tympanomastoidea, in the depth of which the outlet of the mastoid canaliculus, canaliculus mastoideus, starting in the fossa jugularis, opens. The edge is pointed and elongated downward in the form of a ridge, crista peirosa, part of which at the base of the processus styloideus is most developed, is called the styloid sheath, vagina processus styloidei. The lower surface of the tympanic part and the fossa at the root of the zygomatic process of the scaly part form the articular fossa of the lower jaw, fossa mandibularis, at the bottom of which are fissura petrotympanica (Glaseri) and fissura petrosquamosa. This fossa is divided by the glazing slit into two parts - anterior and posterior.
The front part, lined with articular cartilage, faces the cavity of the mandibular joint, it is called inside- or intracapsular part, pars intracapsularis; back - located outside the joint and is called outside-or extracapsular part, pars extracapsularis (see "Mandibular joint").