Temporal bone location. Canals of the temporal bone. Anatomy: temporal bone. drum string channel
25969 0
(os temporale), steam room. It distinguishes three parts located around the external auditory opening: scaly, pyramid (stony part) and tympanic (Fig. 1, 2).
The organs of hearing and balance are located in the temporal bone, vessels and nerves pass through its canals. It is involved in the formation of the temporomandibular joint.
scaly part(pars squamosa) represents a vertically located plate, connected by a free edge with the lower edge of the parietal bone and with a large wing of the sphenoid bone. Below, it is adjacent to the drum and stony parts, separated from them tympanosquamous fissure (fissura tympanosquamosa) and stony-scaly fissure (fissura petrosquamosa)[visible only on the bones of young subjects].
outdoor, temporal surface (fades temporalis), the squamous part is smooth, participates in the formation of the temporal fossa. Below it is limited zygomatic process (processus zygomaticus), which is directed anteriorly, connects to the temporal process of the zygomatic bone, forming the zygomatic arch. At the base of the zygomatic process, a root is distinguished, which forms articular tubercle, and less pronounced articular tubercle (tuberculum retroarticulare), passing into the temporal line. Between the articular and articular tubercles is formed 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 - outside view: 1 - scaly part; 2 - zygomatic process; 3 - articular tubercle; 4 - behind the articular tubercle; 5 - mandibular fossa; 6 - stony-scaly gap; 7 - the edge of the roof of the tympanic cavity; 8 - stony-tympanic fissure; 9 - styloid process; 10 - drum part; 11 - mastoid process; 12 - mastoid notch; 13 - external auditory meatus; 14 - mastoid opening; 15 - supra-passing awn; 16 - temporal line; 17 - furrow of the middle temporal artery;
c - anterior surface of the pyramid of the temporal bone: 1 - parietal edge; 2 - cerebral surface of the scales; 3 - stony-scaly gap; 4 - the roof of the tympanic cavity; 5 - arched elevation; 6 - groove of the sigmoid sinus; 7 - mastoid opening; 8 - occipital margin; 9 - furrow of the upper stony sinus; 10 - the upper edge of the pyramid; 11 - trigeminal depression; 12 - carotid channel; 13 - rocky part; 14 - front surface of the pyramid; 15 - musculo-tubal canal; 16 - wedge-shaped edge; 17 — a furrow of a small stony nerve; 18 - furrow of a large stony nerve; 19 — a fissure of the channel of a small stony nerve; 20 — a cleft of the channel of a big stony nerve;
d - inside view: 1 - scaly part; 2 - semicircular elevation; 3 - roof of the tympanic cavity; 4 - groove of the sigmoid sinus; 5 - mastoid opening; 6 — an aperture of a tubule of a vestibule; 7 - styloid process; 8 - aperture of the tubule of the cochlea; 9 - furrow of the lower stony sinus; 10 - internal auditory meatus; 11 - furrow of the superior sagittal sinus; 12 - zygomatic process;
e - bottom view: 1 - stony-scaly crack; 2 - stony-tympanic fissure; 3 - muscular-tubal channel; 4 - internal aperture of the carotid canal; 5 - the top of the pyramid; 6 - the lower surface of the pyramid; 7 - furrow of the lower stony sinus; 8 - external aperture of the carotid canal; 9 - stony dimple; 10 - condylar tubule; 11 - jugular fossa; 12 - stylomastoid opening; 13 - furrow of the occipital artery; 14 - mastoid notch; 15 - mastoid process; 16 - styloid process; 17 - tympanic scaly fissure; 18 - mandibular fossa; 19 - articular tubercle; 20 - zygomatic process
Rice. 2. Cutting the temporal bone through the tympanic cavity:
1 - arcuate elevation; 2 — a probe in a knee of the channel of a facial nerve; 3 — a furrow of a big stony nerve; 4 - semi-channel of the muscle straining the eardrum; 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
On the outer surface of the squamous part of the temporal bone passes groove of the middle temporal artery (sulcus a. temporalis mediae).
internal, brain surface (fades cerebralis) has cerebral elevations, depressions of the convolutions (finger-shaped); along it pass the furrows of the vessels of the meninges.
Human Anatomy S.S. Mikhailov, A.V. Chukbar, A.G. Tsybulkin
It consists of many elements (channels, furrows, surfaces, tubercles, etc.) and students of medical academies remember how they studied it in Latin as a nightmare.
The temporal bone is located on the border between the cranial vault and the base of the skull. It is connected to almost all other bones of the skull by various types of connections. It contains the organs of balance (vestibular apparatus) and hearing (inner ear). From below, various muscles of the neck are attached to it, from the inside, the carotid artery (internal branch) passes through it, and on the outside there is an auditory opening on its surface. These are far from all the formations that the temporal bone has.
Canals of the temporal bone
There are several canals and tubules in the temporal bone:
- sleepy channel;
- tubules sleepy-tympanic;
- musculo-tubal canal;
- front channel;
- drum tubule;
- drum string tubule;
- mastoid canal.
Each canal of the temporal bone contains a certain anatomical formation. Consider the anatomy of these channels in more detail.
sleepy channel
This canal is named so because it contains the temporal part of the internal carotid artery. The carotid canal (in Latin canalis caroticus) originates from below the temporal bone with an external opening, passes through its thickness upwards and then turns anteriorly almost at a right angle and ends in the cranial cavity. The ICA (internal carotid artery) supplies most of the brain. The carotid artery in the canal is accompanied by veins and a plexus of nerve fibers of the sympathetic nervous system.
Carotid tubules
In Latin - canaliculi caroticotympanici - they are two small tubules that branch off from the carotid canal and lead into the tympanic cavity. Contain these channels carotid-tympanic nerve fibers.
Musculo-tubal canal
In Latin - canalis musculotubarius. It originates from the anterior superior wall of the tympanic cavity. The entrance to the canal is located near the external auditory opening. Inside the channel itself there is a horizontal partition that divides it into two half-channels. In the upper semi-canal lies a muscle that strains the eardrum. It is smaller than the bottom. The lower channel forms an anatomical connection between the pharyngeal cavity (atmospheric pressure) and the tympanic cavity to equalize air pressure on opposite sides of the tympanic membrane. Thanks to this channel, we can always hear the same at various fluctuations in atmospheric pressure. On the other hand, inflammation of the mucous membrane of this canal can lead to inflammatory processes in the tympanic cavity.
front channel
The facial canal (in Latin canalis facialis) originates in the lower part of the internal auditory meatus and runs horizontally. Inside the temporal bone, it turns at a right angle, forming the knee of the facial canal, and exits into the tympanic cavity. Having passed through the latter in the posterior direction, it turns down and goes to the surface of the temporal bone, where it ends with a hole, which is called the stylomastoid because of the proximity of the styloid and mastoid process near it.
Drum string tubule
In Latin - canaliculus chordae tympani. It originates from the facial canal near the stylomastoid foramen and ends in the tympanic cavity. The contents of this canal are the nerve that innervates the anterior two-thirds of the tongue (taste sensations) and the salivary glands (sublingual and submandibular). This nerve is called the drum string.
drum tubule
In Latin - canaliculus tympanicus. It originates on the surface of the temporal bone (its petrous part) and also leads to the tympanic cavity.
mastoid tubule
In Latin - canaliculus mastoideus. It contains the ear branch of the nervus vagus (vagus nerve). It starts in the jugular fossa and leads to the tympanic mastoid fissure.
As you can see, the temporal bone is literally pitted with various channels, tubules, furrows and other anatomical formations. Especially when you consider that its volume (stony part) is slightly larger than the volume of a matchbox. All this is due to the presence in the temporal bone of ultrafine organs of hearing and coordination, which have a rich innervation, as well as blood supply.
Video: Temporal bone - Channels
Canals of the temporal bone
The carotid canal (canalis caroticus), through which the internal carotid artery and the internal carotid (vegetative) plexus pass into the cranial cavity, begins on the lower surface of the pyramid with the external opening of the carotid canal. Further, the carotid canal rises upward, bends at a right angle, goes forward and medially. The canal opens into the cranial cavity with an internal carotid foramen.
The musculoskeletal canal (canalis musculotubarius) has a common wall with the carotid canal. It starts at the anterior edge of the pyramid near its border with the scales of the temporal bone, goes posteriorly and laterally, parallel to the anterior edge of the pyramid. The musculoskeletal canal is divided by a septum into two semi-canals. The upper semi-canal (semicanalis musculi tensoris tympani) is occupied by the muscle of the same name that strains the eardrum, and the lower semi-canal of the auditory tube (semicanalis tubae auditivae) is the bone part of this tube. Both semi-channels open into the tympanic cavity on its anterior wall.
The facial canal (canalis facialis), in which the facial nerve and blood vessels pass, begins at the bottom of the internal auditory canal. Then, in the thickness of the pyramid of the temporal bone, the facial canal goes horizontally forward, perpendicular to the longitudinal axis of the pyramid. Having reached the level of the cleft of the canal of the large stony nerve, the canal leaves laterally and posteriorly at a right angle, forming a bend, or knee of the facial canal (geniculum canalis facialis). Further, the canal follows horizontally posteriorly along the axis of the pyramid to its base, where it turns vertically downward, bending around the tympanic cavity. On the lower surface of the pyramid, the canal ends with an awl-mastoid opening.
The tubule of the drum string (canaliculus chordae tympani) starts from the canal of the facial nerve slightly above the awl-mastoid opening, goes forward and opens into the tympanic cavity. In this tubule passes a branch of the facial nerve - a tympanic string (chorda tympani), which then exits the tympanic cavity through the stony-tympanic fissure.
The tympanic tubule (canaliculus tympanicus) begins with a lower opening in the depths of a stony dimple on the lower surface of the pyramid, then rises upward into the tympanic cavity through its lower wall. Further, the tubule continues in the form of a furrow (sulcus promontorii)
on the labyrinth wall of this cavity on the surface of the cape (promontorium). Then the Canadian perforates the upper wall of the tympanic cavity and ends with a cleft canal of the small stony nerve on the anterior surface of the pyramid. In the tympanic tubule passes the tympanic nerve - a branch of the glossopharyngeal nerve.
The mastoid tubule (canaliculus mastoideus) originates in the jugular fossa, crosses the facial canal in its lower part and opens into the tympanic-mastoid fissure. The auricular branch of the vagus nerve passes through this tubule.
Carotid-tympanic tubules (canaliculi caroticotympanici) begin on the wall of the carotid canal (near its outer opening) and penetrate into the tympanic cavity.
Both tubules serve to pass the nerves and arteries of the same name into the tympanic cavity.
Temporal bone, os temporale, the paired bone has a complex structure, since it performs all 3 functions of the skeleton and not only forms part of the side wall and base of the skull, but also contains the organs of hearing and gravity. It is the product of the fusion of several bones (mixed bone) that exist independently in some animals, and therefore consists of three parts:
1) scaly part, pars squamosa;
2) drum part, pars tympanica and
3) rocky part, pars petrosa.
During the 1st year of life, they merge into a single bone, closing external auditory canal, meatus acusticus externus, in such a way that the scaly part lies above it, the stony part is inward from it, and the tympanic part is behind, below and in front. Traces of the fusion of individual parts of the temporal bone remain for life in the form of intermediate sutures and crevices, namely: on the border of pars squamosa and pars petrosa, on the anteroposterior surface of the latter - fissura petrosquamos a; in the depths of the mandibular fossa - fissura tympanosquamosa, which is divided by the process of the stony part into fissura petrosquamosa and fissura petrotympanica(the chorda tympani nerve comes out through it).
Squamous part, pars squamosa, participates in the formation of the lateral walls of the skull. It belongs to the integumentary bones, i.e., it ossifies on the soil of the connective tissue and has a relatively simple structure in the form of a vertically standing plate with a rounded edge superimposed on the corresponding edge of the parietal bone, margo squamosa, in the form of fish scales, hence its name.
On its cerebral surface, facies cerebralis, traces of the brain are visible, digital impressions, impressiones digitatae, and ascending groove from a. meningea media. The outer surface of the scales is smooth, participates in the formation of the temporal fossa (the anatomy of which is considered) and therefore is called facies temporalis.
Departs from her zygomatic process, processus zygomaticus, which goes forward at the connection with the zygomatic bone. At its beginning, the zygomatic process has two roots: anterior and posterior, between which there is a fossa for articulation with the lower jaw, fossa mandibularis.
On the lower surface of the anterior root is placed articular tubercle, tuberculum articulare, preventing dislocation of the head of the lower jaw forward with a significant opening of the mouth.
Drum part, pars tympanica, the temporal bone forms the anterior, lower and part of the posterior edge of the external auditory canal, ossifies endesmally and, like all integumentary bones, has the form of a plate, only sharply curved.
External auditory canal, meatus acusticus externus, is a short channel, heading inward and somewhat forward and leading into the tympanic cavity. Its top edge external opening, porus acusticus externus, and part of the posterior edge are formed by the scales of the temporal bone, and for the rest of the length - by the tympanic part.
In a newborn, the external auditory canal has not yet been formed, since the tympanic part is an incomplete ring (annulus tympanicus), tightened by the tympanic membrane. Due to such a close location of the tympanic membrane outward, newborns and young children are more often observed diseases of the tympanic cavity.
The stony part, pars petrosa, is so named for the strength of its bone substance, due to the fact that this part of the bone is involved in the base of the skull, and is the bone receptacle of the organs of hearing and gravity, which have a very thin structure and need strong protection from damage. It develops on the basis of cartilage. The second name of this part is the pyramid, given by its shape of a trihedral pyramid, the base of which is turned outward, and the top is forward and inward to the sphenoid bone.
The pyramid has three surfaces: front, back and bottom. The anterior surface is part of the bottom of the middle cranial fossa; the posterior surface faces posteriorly and medially and forms part of the anterior wall of the posterior cranial fossa; the lower surface is turned downwards and is visible only on the outer surface of the base of the skull. The external relief of the pyramid is complex and due to its structure as a container for the middle (tympanic cavity) and inner ear (a bony labyrinth consisting of the cochlea and semicircular canals), as well as the passage of nerves and blood vessels.
On the front surface of the pyramid, near its top, there is a slight depression, impressio trigemini, from the node of the trigeminal nerve (n. trigemini,). Outside of it pass two thin grooves, medial - sulcus n. petrosi majoris, and lateral - sulcus n. petrosi minoris. They lead to two openings of the same name: medial, hiatus candlis n. petrosi majoris, and lateral, hiatus canalis n. petrosi minoris. Outside of these holes, an arched elevation is noticeable, eminentia arcuata, formed due to the protrusion of a rapidly developing labyrinth, in particular the upper semicircular canal.
The surface of the bone between eminentia arcuata and squama temporalis forms the roof of the tympanic cavity, tegmen tympani.
Approximately in the middle of the back surface of the pyramid is internal auditory opening, porus acusticus internus, which leads to internal auditory canal, meatus acusticus internus where the facial and auditory nerves pass, as well as the artery and veins of the labyrinth.
From the lower surface of the pyramid, facing the base of the skull, a thin pointed styloid process, processus styloideus serving as an attachment site for muscles "anatomical bouquet"(mm. styloglossus, stylohyoideus, stylopharyngeus), as well as ligaments - ligg. stylohyoideum and stylomandibular. The styloid process is part of the temporal bone of branchial origin. Together with lig. stylohyoideum, it is a remnant of the hyoid arch.
Between the styloid and mastoid processes is stylomastoid foramen, foramen stylomastoideum, through which n exits. facialis and a small artery enters. Medially from the styloid process is a deep jugular fossa, fossa jugularis. Anterior to the fossa jugularis, separated from it by a sharp ridge, is the outer opening of the carotid canal, foramen caroticum externum.
The pyramid has three edges: front, back and top. The short anterior margin forms an acute angle with the scales. In this corner, one can see orifice of the musculotube canal, candlis musculo tubarius leading to the tympanic cavity. This channel is divided by a partition into two sections: upper and lower. Upper, smaller semi-canal, semicanalis m. tensoris tympani, contains this muscle, and the lower, larger, semicandlis tubae auditivae, is the bony part of the auditory tube, which serves to conduct air from the pharynx into the tympanic cavity.
Along the upper edge of the pyramid, separating the anterior and posterior surfaces, there is a clearly visible groove, sulcus sinus petrosi superiors, - a trace of the venous sinus of the same name.
Rear edge of the pyramid anterior to the fossa jugularis connects to the basilar part of the occipital bone and forms with this bone sulcus sinus petrosi inferioris- a trace of the lower stony venous sinus.
The outer surface of the base of the pyramid serves as a place of muscle attachment, which is the reason for its outer relief (process, notches, roughness). From top to bottom, it stretches into mastoid process, processus mastoideus. The sternocleidomastoid muscle is attached to it, which maintains the head in balance, necessary for the vertical position of the body. Therefore, the mastoid process is absent in tetrapods and even anthropoid apes and develops only in humans due to their upright posture.
On the medial side of the mastoid process there is a deep mastoid notch, incisura mastoidea, - the place of attachment m. digastricus; even more inwards - a small furrow, sulcus a. occipitalis, - a trace of the artery of the same name.
On the outer surface of the base of the mastoid process, a smooth triangle is isolated, which is a place for quick access to the cells of the mastoid process when they are filled with pus.
Inside the mastoid process and contains these cells of cellulae mastoideae, which are air cavities separated by bone crossbars, receiving air from the tympanic cavity, with which they communicate through antrum mastoideum. On the cerebral surface of the base of the pyramid passes deep furrow, sulcus sinus sigmoidei where the venous sinus of the same name lies.
Canals of the temporal bone. The largest channel is canalis caroticus through which the internal carotid artery passes. Starting with its external opening on the lower surface of the pyramid, it rises upward, then bends at a right angle and opens with its internal opening at the top of the pyramid medially from the canalis musculotubarius.
Facial canal, canalis facialis, starts in depth porus acusticus internus, from where the canal first goes forward and laterally to the cracks (hiatus) on the anterior surface of the pyramid; at these holes, the canal, remaining horizontal, turns at a right angle laterally and backward, forming a bend - knee, geniculum canalis facialis, and then down and ends through the foramen stylomastoideum, located on the lower surface of the pyramid of the temporal bone, canalis musculotubarius.
