Antipyretics for children are prescribed by a pediatrician. But there are emergency situations for fever when the child needs to be given medicine immediately. Then the parents take responsibility and use antipyretic drugs. What is allowed to give to infants? How can you bring down the temperature in older children? What medicines are the safest?
Orbit- a closed space containing a large number of complex anatomical structures that ensure the vital activity and functions of the organ of vision. The close apathomo-toiographic connection of the orbit with the cranial cavity, paranasal sinuses causes the same type of symptoms in many, sometimes absolutely various diseases, exacerbates the course of the pathological process in the orbit (tumor, inflammatory) and, of course, presents great difficulties in carrying out orbital operations.
Bone orbit is a geometric figure similar in shape to a tetrahedral pyramid, the apex of which is directed backwards and somewhat medially (at an angle of 45 ° with respect to the sagittal axis). The shape of the anterior part of the orbit can be close to round, but more often the diameters in the vertical and horizontal directions vary (on average, they are about 35 and 40 mm, respectively).
V.V. Valsky in the study of dimensions orbits by using computed tomography(CT) in 276 healthy individuals, it was found that the horizontal diameter of the orbit at the entrance is on average 32.6 mm in men and 32.7 mm in women. In the middle third, the diameter of the orbit is almost halved and reaches 18.2 mm in men and 16.8 mm in women. The depth of the orbit is also variable (from 42 to 50 mm). According to the shape, one can distinguish a short and wide (with such an orbit, its depth is the smallest), a narrow and long orbit, in which the greatest depth is noted.
Distance from the posterior pole of the eye to the top of the orbit in men is on average 25.6 mm, in women - 23.5 mm. The bone walls are unequal in thickness and length: the most powerful outer wall, especially closer to the edge of the orbit, the thinnest - the inner and upper. The length of the outer wall ranges on average from 41.2 mm in women to 41.6 mm in men.
outer wall formed by the zygomatic, partially frontal and large wing of the main bone. The thickest is the zygomatic bone, but towards the back it becomes thinner and its thinnest section is located at the junction with the large wing of the main bone. This structural feature of the zygomatic bone plays an important role in bone operations in orbit; a thick anterior surface makes it possible to preserve the integrity of the bone flap at the time of its fixation during wall resection, and in a thin area, a fracture easily occurs at the moment of bone traction. The outer wall borders on the temporal fossa, at the top of the orbit - on the middle cranial fossa.
bottom wall- the orbital surface of the maxillary bone, and the anterior-outer section - the zygomatic bone and the orbital process. In the lateral part of the lower wall, near the lower orbital fissure, there is an infraorbital groove - a depression covered with a connective tissue membrane. The furrow gradually passes into the bone canal, which opens on the anterior surface of the maxillary bone 4 mm from the lower orbital edge closer to its outer border.
Through channel pass the lower orbital nerve, artery and vein of the same name. The thickness of the lower orbital wall is 1.1 mm. This bony septum separates the contents of the orbit from the maxillary sinus and requires very gentle manipulation. When exentering the orbit, lower subperiosteal orbitotomy, the surgeon must take into account the thickness of the lower wall in order to avoid surgical fracture of the wall.
Inner wall formed by the lacrimal bone, lamina lamina, lamina ethmoid, frontal process of the maxillary bone and body of the sphenoid bone. The largest of them is a paper plate 0.2 mm thick, which separates the orbit from the cells of the lattice labyrinth. In this area, the wall is almost vertical, which is important to consider when cutting off the periosteum during subperiosteal orbitotomy or orbital insertion. In the anterior part of the inner wall, the lacrimal bone curves towards the nose, and there is also a recess for the lacrimal sac.
Upper wall of the orbit triangular in shape and is formed in the anterior and middle sections by the frontal bone, in the posterior - by the small wing of the main bone. The orbital part of the frontal bone is thin and fragile, especially in the posterior 2/3 of it, where the wall thickness does not exceed 1 mm. In the elderly, the bone substance of the upper wall can be gradually replaced by fibrous tissue. This should be taken into account when preparing elderly patients for surgery. In addition, the assessment of the state of the upper wall of the orbit helps to develop tactics for managing patients with tumor or inflammatory lesions of the orbit.
Top wall borders on the frontal sinus, which in the frontal direction can extend to the middle of the wall, and in the anteroposterior direction - sometimes up to the middle third of the orbit. Throughout the surface of the upper wall of the orbit is smooth, in the middle third of it there is a concavity, in the outer and inner sections there are two recesses for the lacrimal gland (lacrimal fossa) and for the block of the superior oblique muscle.
Vertex orbits coincides with the beginning of the optic nerve drip, the diameter of which reaches 4 mm, and the length is 5-6 mm. Through its external opening, enters the orbit optic nerve and usually the ophthalmic artery.
Or the orbit, orbita, is a paired four-sided cavity, cavitas orbitalis (LNA), resembling a pyramid, which contains the organ of vision. It has an entrance to the orbit, aditus orbitalis, which is limited by the orbital margin, margo orbitalis. The depth of the orbit in an adult is from 4 to 5 cm, the width is about 4 cm. It is important to take this into account in clinical practice when probing the wounds of the orbit, inserting a needle during injections. The orbit is limited by four walls: upper, lower, medial and lateral, lined with periosteum, periorbita.
Top wall, paries superior, is formed by the orbital surface of the frontal bone and the lesser wing of the sphenoid bone. It separates the orbit from the anterior cranial fossa and the brain.
bottom wall, paries inferior, is formed by the orbital surface of the upper jaw, the zygomatic bone and the orbital process of the palatine bone. The lower wall is the roof of the maxillary sinus (maxillary sinus), which should be considered in clinical practice.
medial wall, paries medialis, formed by the frontal process of the upper jaw, the lacrimal bone, the orbital plate of the ethmoid bone, the body of the sphenoid bone and partially the orbital surface of the frontal. The medial wall is thin and has a number of openings for the passage of blood vessels and nerves. This circumstance easily explains the penetration of pathological processes from the lattice cells into the orbit and vice versa.
Lateral wall, paries lateralis, is formed by the orbital surface of the zygomatic bone and the greater wing of the sphenoid bone, as well as the ophthalmic part of the frontal bone. It separates the orbit from the temporal.
In the orbit, we observe a number of holes and crevices, with the help of which it is combined with other formations of the skull: the optic nerve canal, canalis opticus, lower orbital fissure, fissura orbitalis inferior, superior orbital fissure; fissura orbitalis superior, zygomatic-orbital foramen, foramen zygomaticoorbitale; nasolacrimal canal, canalis nasolacrimalis, anterior and posterior ethmoid openings, foramen ethmoidalis anterior et posterior.
In the depths of the orbit, on the border between the upper and lateral walls, there is a gap in the form of a comma (superior orbital fissure, fissura orbitalis superior), formed by the body of the sphenoid bone, its large and small wings. It connects the orbit to the cranial cavity (middle cranial fossa). All motor nerves pass through the superior orbital fissure. eyeball: oculomotor, n. oculomotorus, blocky, n. trochlearis, efferent, n. abducens, and optic nerve, n. ophthalmicus, and the main venous collector of the orbit (superior ophthalmic vein, v. ophthalmica superior). The concentration within the upper orbital fissure of a number of important formations explains in the clinic the occurrence of a peculiar symptom complex, which, when this area is affected, is called the syndrome of the superior orbital fissure.
On the border between the lateral and lower walls of the orbit passes the lower orbital fissure, fissura orbitalis inferior. It is limited by the lower edge of the large wing of the sphenoid bone and the body of the upper jaw. In the anterior part, the gap connects the orbit with the infratemporal, and in the back - with the pterygopalatine fossa. Venous anastomoses pass through the inferior orbital fissure, connecting the veins of the orbit with the venous plexus of the pterygopalatine fossa and the deep vein of the face, v. facialis profunda.
17-09-2012, 16:51
Description
Eye socket shape
The eye socket contains
- eyeball,
- external muscles of the eye
- nerves and blood vessels
- adipose tissue, with
- iron gland.
Rice. 2.1.1. View of the right and left eye sockets from the front (a) and from the side at an angle of 35 degrees (b) (according to Henderson, 1973): a - the camera is placed along the median axis of the skull. The right visual opening is slightly covered by the medial wall of the orbit. The left optic opening is slightly visible in the form of a small depression (small arrow). The large arrow points to the supraorbital fissure; b - the camera is placed at an angle of 35 degrees relative to the midline. The optic canal (small arrow) and the superior orbital fissure (large arrow) are clearly visible..
Rice. 2.1.2. Ocular and orbital axes and their relationship
Rice. 2.1.3. Bones that form the eye socket: 1 - orbital process of the zygomatic bone; 2 - zygomatic bone; 3 - frontal-sphenoid process of the zygomatic bone: 4 - orbital surface of the large wing of the sphenoid bone; 5 - large wing of the sphenoid bone; 6 - lateral process of the frontal bone; 7 - fossa of the lacrimal gland; 8 - frontal bone; 9 - visual aperture; 10 - supraorbital notch; 11 - block hole; 12 - ethmoid bone; 13 - nasal bone; 14 - frontal process of the upper jaw; 15 - lacrimal bone; 16 - upper jaw; 17 - infraorbital foramen; 18 - palatine bone; 19 - infraorbital sulcus; 20 infraorbital fissure; 21-zygomatic-facial opening; 22-superior orbital fissure
The medial walls of the orbit are almost parallel, and the distance between them is 25 mm. The outer walls of the orbit in adults are located relative to each other at an angle of 90 °. Thus, the divergent axis of the orbit is half 45°, i.e. 22.5° (Fig. 2.1.2).
Linear and volumetric dimensions of the eye socket hesitate at different people over a fairly wide range. However, the averages are as follows. The widest part of the orbit is located at a distance of 1 cm from its anterior edge and is 40 mm. The greatest height is approximately 35 mm, and the depth is 45 mm. Thus, in an adult, the volume of the eye socket is approximately 30 cm3.
Forms the eye socket seven bones:
- ethmoid bone (os ethmoidale),
- frontal bone (os frontale),
- lacrimal bone (os lacrimale),
- maxillary bone (maxilla),
- palatine bone (os palatimim),
- sphenoid bone
- and zygomatic bone (os zigomaticum).
Edges of the eye socket
In an adult, the shape of the edge of the orbit (margoorbitalis) is a quadrilateral with a horizontal dimension of 40 mm, and a vertical dimension of 32 mm (Fig. 2.1.3).
The largest part of the outer edge (margo lateralis) and the outer half of the lower edge (margo infraorbitalis) of the orbit forms cheekbone. The outer edge of the orbit is quite thick and can withstand heavy mechanical loads. When a bone fracture occurs in this area, it usually follows the line of suture propagation. In this case, the fracture occurs both along the line of the zygomatic-maxillary suture in the downward direction or down-outward along the line of the zygomatic-frontal suture. The direction of the fracture depends on the site of application of the traumatic force.
frontal bone forms the upper edge of the orbit (margo siipraorbitalis), and its outer and inner parts are involved in the formation of the outer and inner edges of the orbit, respectively. In newborns, the upper edge is sharp. It remains sharp in women throughout life, and in men it rounds off with age. On the upper edge of the orbit from the medial side, the supraorbital notch (incisura frontalis) is visible, containing the supraorbital nerve (n. siipraorbitalis) and vessels. In front of the artery and nerve and slightly outward relative to the supraorbital notch, there is a small supraorbital foramen (foramen supraorbitalis), through which the artery of the same name (arteria siipraorbitalis) penetrates into the frontal sinus and spongy part of the bone.
Inner edge of the eye socket(margo medialis orbitae) in the anterior sections is formed by the maxillary bone, which extends the process to the frontal bone.
The configuration of the inner edge of the orbit is complicated by the presence in this area lacrimal scallops. For this reason, Whitnall proposes to consider the shape of the inner edge as a wavy spiral (Fig. 2.1.3).
Lower edge of the eye socket(margo inferior orbitae) is formed by half the maxillary and half the zygomatic bones. The infraorbital nerve (n. infraorbitalis) and the artery of the same name pass through the lower edge of the orbit from the inside. They come to the surface of the skull through the infraorbital foramen (foramen infraorbitalis), located somewhat medially and below the lower edge of the orbit.
Bones, walls and openings of the orbit
As indicated above, the orbit is formed by only seven bones, which are also involved in the formation of the facial skull.
medial walls eye sockets are parallel. They are separated from each other by the sinuses of the ethmoid and sphenoid bones. Lateral walls separate the orbit from the middle cranial fossa behind and from the temporal fossa - in front. The orbit is located directly below the anterior cranial fossa and above the maxillary sinus.
Upper wall of the orbit (Paries superior orbitae)(Fig. 2.1.4).
Rice. 2.1.4. Upper wall of the orbit (according to Reeh et, al., 1981): 1 - orbital wall of the frontal bone; 2- fossa of the lacrimal gland; 3 - front lattice hole; 4 - a large wing of the sphenoid bone; 5 - upper orbital fissure; 6 - lateral orbital tubercle; 7 - block hole; 8 - posterior crest of the lacrimal bone; 9 - anterior crest of the lacrimal bone; 10 - sutura notra
The upper wall of the orbit is adjacent to the frontal sinus and to the anterior cranial fossa. It is formed by the orbital part of the frontal bone, and behind - by the lesser wing of the sphenoid bone. The sphenofrontal suture (sutura sphenofrontalis) passes between these bones.
On the upper wall of the orbit there is a large number of formations that play the role of "marks" used in surgical interventions. In the anterolateral part of the frontal bone is the fossa of the lacrimal gland (fossa glandulae lacrimalis). The fossa contains not only the lacrimal gland, but also a small amount of adipose tissue, mainly in the posterior part (the accessory fossa of Pout Dovigneaud (Roch on-Duvigneaud)). From below, the fossa is limited by the zygomatic-frontal suture (s. frontozigomatica).
The surface of the bone in the region of the lacrimal fossa is usually smooth, but roughness is sometimes determined at the site of attachment of the supporting ligament of the lacrimal gland.
In the anteromedial part, approximately 5 mm from the edge, are located trochlear fossa and trochlear spine(fovea trochlearis et spina trochlearis), on the tendon ring of which the superior oblique muscle is attached.
Through the supraorbital notch, located on the upper edge of the frontal bone, passes supraorbital nerve, which is a branch of the frontal branch of the trigeminal nerve.
At the top of the orbit, directly at the lesser wing of the sphenoid bone, is located visual aperture- entrance to the optic canal (canalis opticus).
The upper wall of the orbit is thin and fragile. It thickens up to 3 mm at the site of formation of its small wing of the sphenoid bone (ala minor os sphenoidale).
The greatest thinning of the wall is observed in cases where the frontal sinus. Sometimes with age, resorption of the bone tissue of the upper wall occurs. In this case, the periorbita is in contact with the dura mater of the anterior cranial fossa.
Since the upper wall is thin, it is in this area that fracture occurs when a bone is injured with the formation of sharp bone fragments. Through the upper wall, various pathological processes (inflammation, tumors) that develop in the frontal sinus spread into the orbit. It is necessary to pay attention to the fact that the upper wall is located on the border with the anterior cranial fossa. This circumstance is of great practical importance, since injuries to the upper wall of the orbit are often combined with brain damage.
The inner wall of the orbit (Paries tedialis orbitae)(Fig. 2.1.5).
Rice. 2.1.5. The inner wall of the orbit (according to Reeh et al, 1981): 1 - anterior lacrimal scallop and frontal process of the upper jaw; 2- lacrimal fossa; 3 - posterior lacrimal scallop; 4- lamina parugasea of the ethmoid bone; 5 - front lattice hole; 6-optic opening and canal, superior orbital fissure and spina recti lateralis; 7 - lateral angular process of the frontal bone: 8 - inferoorbital margin with zygomatico-facial opening located on the right
The inner wall of the orbit is the thinnest (0.2-0.4 mm thick). It is formed by 4 bones:
- orbital plate of the ethmoid bone (lamina orbitalis os ethmoidale),
- frontal process of the upper jaw (processus frontalis os zigomaticum),
- lacrimal bone
- and the lateral orbital surface of the sphenoid bone (fades orbitalis os sphenoidalis), located most deeply.
In front of the inner wall is visible tear trough(sulcus lacrimalis), continuing into the fossa of the lacrimal sac (fossa sacci lacrimalis). It contains the lacrimal sac. The tear trough, as it moves downward, passes into the lacrimal canal (canalis nasolacrimalis).
The boundaries of the lacrimal fossa are delineated by two ridges - anterior and posterior lacrimal crests(crista lacrimalis anterior et posterior). The anterior lacrimal crest continues down and gradually passes into the lower edge of the orbit.
The anterior lacrimal crest is easily palpable through the skin and is a marker during operations on the lacrimal sac.
As mentioned above, the main part of the inner wall of the orbit is represented by the ethmoid bone. Since it is the thinnest of all the bone formations of the orbit, it is through it that the inflammatory process most often spreads from the sinuses of the ethmoid bone to the tissues of the orbit. This can lead to the development of cellulitis, phlegmon of the orbit, thrombophlebitis of the veins of the orbit, toxic neuritis of the optic nerve, etc. Children often develop acutely developing ptosis. The inner wall is also the site of the spread of tumors from the sinus to the orbit and vice versa. Often it is destroyed during surgical interventions.
The inner wall is somewhat thicker only in the posterior sections, especially in the region of the body of the sphenoid bone, as well as in the region of the posterior lacrimal crest.
Ethmoid bone, which is involved in the formation of the inner wall, contains numerous air-containing bone formations, which can explain the rarer occurrence of fractures of the medial wall of the orbit than the thick bottom of the orbit.
It should also be mentioned that in the area of \u200b\u200bthe lattice seam, often there are anomalies in the development of bone walls, for example, congenital "gaping", significantly weakening the wall. In this case, the bone tissue defect is covered with fibrous tissue. The weakening of the inner wall also occurs with age. The reason for this is atrophy of the central parts of the bone plate.
In practical terms, especially when performing anesthesia, it is important to know the location of the anterior and posterior ethmoidal foramina through which the branches of the ophthalmic artery, as well as the branches of the nasociliary nerve, pass.
The anterior ethmoid openings open at the anterior end of the fronto-ethmoid suture, and the posterior ones near the posterior end of the same suture (Fig. 2.1.5). Thus, the anterior openings lie 20 mm behind the anterior lacrimal crest, and the posterior openings lie 35 mm behind.
In the depths of the orbit on the inner wall is located visual channel(canalis opticus), communicating the cavity of the orbit with the cavity of the skull.
The outer wall of the orbit (Paries lateralis orbitae)(Fig. 2.1.6).
Rice. 2.1.6. The outer wall of the orbit (according to Reeh et al, 1981): 1 - frontal bone; 2 - a large wing of the sphenoid bone; 3 - zygomatic bone; 4 - upper orbital fissure; 5 - spina recti lateralis; 6 - infraorbital fissure; 7 - opening through which a branch passes from the zygomatic-orbital nerve to the lacrimal gland; 8 - zygomatic-orbital opening
The outer wall of the orbit in its posterior section separates the contents of the orbit and the middle cranial fossa. In front, it borders on the temporal fossa (fossa temporalis), made by the temporal muscle (t. temporalis). It is delimited from the upper and lower walls by the orbital fissures. These boundaries extend in front to the sphenofrontal (sutura sphenofrontalis) and zygomatic-maxillary (sutura zigomaticomaxilare) sutures (Fig. 2.1.6).
Posterior part of the outer wall of the orbit forms only the orbital surface of the greater wing of the sphenoid bone, and the anterior section - the orbital surface of the zygomatic bone. Between them is the wedge-zygomatic suture (sutura sphenozigomatica). The presence of this suture greatly simplifies the orbitotomy.
On the body of the sphenoid bone at the junction of the wide and narrow parts of the upper orbital fissure is located small bony prominence(thorn) (spina recti lateralis), from which the external rectus muscle begins.
On the zygomatic bone near the edge of the orbit is located zygomatico-orbital foramen(i. zigomaticoorbitale), through which the orbit leaves the branch of the zygomatic nerve (p. zigomatico-orbitalis), heading to the lacrimal nerve. In the same area, the orbital eminence (eminentia orbitalis; Whitnell's orbital tubercle) is also found. Attached to it is the external ligament of the eyelid, the external "horn" of the levator, the ligament of Lockwood (lig. suspensorium), the orbital septum (septum orbitale) and the lacrimal fascia (/. lacrimalis).
The outer wall of the orbit is the place of the easiest access to the contents of the orbit during various surgical interventions. The spread of the pathological process to the orbit from this side is extremely rare and is usually associated with diseases of the zygomatic bone.
When performing an orbitotomy, the ophthalmic surgeon must be aware that the posterior edge of the incision is separated from the middle cranial fossa at a distance of 12-13 mm in men and 7-8 mm in women.
Inferior wall of the orbit (Paries inferior orbitae)(Fig. 2.1.7).
Rice. 2.1.7. Inferior wall of the orbit (according to Reeh et al., 1981): 1 - lower orbital margin, maxillary part; 2 - infraorbital foramen; 3- orbital plate of the upper jaw; 4 - infraorbital groove; 5 - orbital surface of the large wing of the sphenoid bone; 6 - marginal process of the zygomatic bone; 7 - lacrimal fossa; 8 - infraorbital fissure; 9 - the place of the beginning of the lower oblique muscle
The bottom of the orbit is also the roof of the maxillary sinus. Such a neighborhood is important in practical terms, since in diseases of the maxillary sinus, the orbit is often affected and vice versa.
Inferior wall of the orbit made up of three bones:
- the orbital surface of the upper jaw (fades orbitalis os maxilla), which occupies most of the bottom of the orbit,
- zygomatic bone (os zygomaticus)
- and the orbital process of the palatine bone (processus orbitalis os zigomaticus) (Fig. 2.1.7).
The shape of the lower wall of the orbit resembles an equilateral triangle.
Between the lower edge of the orbital surface of the sphenoid bone (fades orbitalis os sphenoidalis) and the posterior edge of the orbital surface of the maxillary bone (fades orbitalis os maxilla) is located inferior orbital fissure(fissura orbitalis inferior). The line that can be drawn through the axis of the inferior orbital fissure forms the outer border of the inferior wall. The internal border can be determined along the course of the anterior and posterior ethmoid-maxillary sutures.
On the lateral edge of the lower surface of the maxillary bone begins infraorbital groove(groove) (sulcus infraorbitalis), which, as we move forward, turns into a channel (canalis infraorbitalis). They contain the infraorbital nerve (n. infraorbitalis). In the embryo, the infraorbital nerve lies freely on the bony surface of the orbit, but gradually sinks into the rapidly growing maxillary bone.
The external opening of the infraorbital canal is located under the lower edge of the orbit at a distance of 6 mm (Fig. 2.1.3, 2.1.5). In children, this distance is much less.
Inferior wall of the orbit has different densities. It is denser near and somewhat outside the infraorbital nerve. Inside, the wall becomes noticeably thinner. It is in these places that post-traumatic fractures are localized. The lower wall is also the site of the spread of inflammatory and tumor processes.
The optic canal (Canalis opticus)(Fig. 2.1.3, 2.1.5, 2.1.8).
Rice. 2.1.8. Orbital apex (according to Zide and Jelks, 1985): 1 - infraorbital fissure; 2- round hole; 3- upper orbital fissure; 4-optic opening and optic canal
Several inside the upper orbital fissure is the optic opening, which is the beginning of the visual canal. Separates the optic opening from the upper orbital fissure at the junction of the lower wall of the lesser wing of the sphenoid bone, the body of the sphenoid bone with its lesser wing.
The opening of the optic canal facing the orbit has dimensions of 6-6.5 mm in the vertical plane and 4.5-5 mm in the horizontal (Fig. 2.1.3, 2.1.5, 2.1.8).
visual channel leads to middle cranial fossa(fossa cranialis media). Its length is 8-10 lilas. The axis of the optic canal is directed downward and outward. The deviation of this axis from the sagittal plane, as well as downward, relative to the horizontal plane, is 38°.
The optic nerve (n. opticus), the ophthalmic artery (a. ophtalmica), immersed in the sheaths of the optic nerve, and also the trunks of the sympathetic nerves pass through the canal. After entering the orbit, the artery lies below the nerve, and then crosses the nerve and is located outside.
Since the position of the ophthalmic artery changes in the embryonic period, the canal takes the form of a horizontal oval in the posterior section and a vertical oval in the anterior one.
Already to three years old the optic canal reaches its normal size. Its diameter of more than 7 mm should already be considered a deviation from the norm and suggest the presence of a pathological process. A significant increase in the visual channel is observed with the development of various pathological processes. In young children, it is necessary to compare the diameter of the optic canal on both sides, since it has not yet reached the final dimensions. If different diameters of the optic canals (at least 1 mm) are detected, one can quite confidently assume the presence of an anomaly in the development of the optic nerve or a pathological process localized in the canal. In this case, the most frequently found gliomas of the optic nerve, aneurysms in the sphenoid bone, intraorbital spread of tumors of the optic chiasm. It is quite difficult to diagnose intratubular meningiomas. Any long-term optic neuritis may indicate the possibility of developing intratubular meningioma.
A large number of other diseases leads to the expansion of the visual channel. This benign hyperplasia arachnoid, fungal lesions (mycoses), granulomatous inflammatory reaction (syphilitic gumma, tuberculoma). Channel dilatation also occurs in sarcoidosis, neurofibroma, arachnoiditis, arachnoid cyst, and chronic hydrocephalus.
The narrowing of the channel is possible with fibrous dysplasia or fibroma of the sphenoid bone.
Superior orbital fissure (Fissura orbitalis superior).
The shape and size of the upper orbital fissure differ significantly among different individuals. It is located on the outer side of the visual opening at the top of the orbit and has the shape of a comma (Fig. 2.1.3, 2.1.6, 2.1.8, 2.1.9).
Rice. 2.1.9. Location of structures in the region of the maxillary fissure and zinn ring (according to Zide and Jelks, 1985): 1 - external rectus muscle; 2-upper and lower branches of the oculomotor nerve; 3- frontal nerve; 4- lacrimal nerve; 5 - block nerve; 6 - upper rectus muscle; 7 - nasociliary nerve; 8 - levator of the upper eyelid; 9 - upper oblique muscle; 10 - abducens nerve; 11 - internal rectus muscle; 12 - lower rectus muscle
It is limited by the small and large wings of the sphenoid bone. The upper part of the superior orbital fissure is narrower on the lateral side than on the medial side and from below. At the junction of these two parts is the spine of the rectus muscle (spina recti).
Pass through the superior orbital fissure
- oculomotor,
- trochlear nerves,
- I branch of the trigeminal nerve
- abducens nerve,
- supraorbital vein,
- recurrent lacrimal artery,
- sympathetic root of the ciliary ganglion (Fig. 2.1.9).
Common tendon ring(anulus tendineus communis; zinn ring) is located between the upper orbital fissure and the optic canal. The optic nerve, the ophthalmic artery, the upper and lower branches of the trigeminal nerve, the nasociliary nerve, the abducens nerve, and the sympathetic roots of the trigeminal ganglion enter the orbit through the Zinn ring and are thus located in the muscular funnel (Fig. 2.1.8, 2.1.9).
Immediately under the ring in the upper orbital fissure passes superior branch of the inferior ophthalmic vein(v. ophthalmica inferior). Outside the ring from the lateral side of the upper orbital fissure pass trochlear nerve(n. trochlearis), superior ophthalmic vein (v. ophthalmica superior), as well as the lacrimal and frontal nerves (nn. lacrimalis et frontalis).
The expansion of the superior orbital fissure may indicate the development of various pathological processes, such as aneurysm, meningioma. chordoma. pituitary adenoma, benign and malignant tumors of the orbit.
Sometimes an inflammatory process of an unclear nature develops in the region of the upper orbital fissure (Talas-Hant syndrome, painful ophthalmoplegia). It is possible that inflammation spreads to the nerve trunks that go to the external muscles of the eye, which is the cause of the pain that occurs with this syndrome.
The inflammatory process in the region of the upper orbital fissure can lead to violation of the venous drainage of the orbit. The consequence of this is swelling of the eyelids and eye sockets. Tuberculous encephalic periostitis has also been described, extending to structures located in the intraorbital fissure.
Inferior orbital fissure (Fissura orbitalis inferior)(Fig. 2.1.7-2.1.10).
Rice. 2.1.10. Temporal, infratemporal and pterygopalatine fossae: 1 - temporal fossa; 2-pterygopalatine fossa; 3 - oval hole; 4 - pterygopalatine opening; 5 - infraorbital fissure; 6 - eye socket; 7 - zygomatic bone; 8 - alveolar process of the upper jaw
The inferior orbital fissure is located in the posterior third of the orbit between the bottom and the outer wall. Outside, it is limited by a large wing of the sphenoid bone, and on the medial side by the palatine and maxillary bones.
The axis of the infraorbital fissure corresponds to the anterior projection of the visual opening and lies at a level corresponding to the lower edge of the orbit.
The infraorbital fissure extends forward more than the upper orbital fissure. It ends at a distance of 20 mm from the edge of the orbit. It is this point that is the reference point for the posterior border during subperiosteal removal of the bone of the lower wall of the orbit.
Directly below the inferior orbital fissure and on the outer side of the orbit is located pterygopalatine fossa(fossa ptervgo-palatina), and in front - temporal fossa(fossa temporalis), performed by the temporal muscle (Fig. 2.1.10).
Blunt trauma to the temporal muscle can lead to hemorrhage into the orbit as a result of destruction of the vessels of the pterygopalatine fossa.
Behind the infraorbital fissure in the greater wing of the sphenoid bone is located round hole(foramen rotundum), connecting the middle cranial fossa with the pterygopalatine fossa. Branches of the trigeminal nerve, in particular the maxillary nerve (n. maxillaris), penetrate into the orbit through this opening. When leaving the hole, the maxillary nerve gives off a branch - infraorbital nerve(n. infraorbitalis), which, together with the infraorbital artery (a. infraorbitalis), enters the orbit through the infraorbital fissure. Subsequently, the nerve and artery are located under the periosteum in the infraorbital groove (sulcus infraorbitalis), and then pass into the infraorbital canal (foramen infraorbitalis) and exit to the facial surface of the maxillary bone at a distance of 4-12 mm below the middle of the orbital margin.
Through the lower orbital fissure from the infratemporal fossa (fossa infratemporalis) also penetrate into the orbit zygomatic nerve(n. zigomaticus), a small branch of the pterygopalatine ganglion (gangsphenopalatina) and veins (lower eye), draining blood from the orbit to the pterygoid plexus (plexus pterygoideus).
In the orbit, the zygomatic nerve divides into two branches- zygomatic-facial (r. zigomaticofacialis) and zygomatic-temporal (n. zigomaticotemporalis). Subsequently, these branches penetrate into the canals of the same name in the zygomatic bone on the outer wall of the orbit and branch out in the skin of the zygomatic and temporal regions. From the zygomatic-temporal nerve towards the lacrimal gland, the nerve trunk is separated, which carries secretory fibers.
The inferior orbital fissure is closed by Müller's smooth muscle. In lower vertebrates, contracting, this muscle leads to protrusion of the eye.
Soft tissues of the eye socket
Having outlined the basic information regarding the bone formations of the orbit, it is necessary to focus on its contents. The content of the orbit is a complex complex of anatomical formations that have different functional significance and belong to different tissues both in origin and in structure (Fig. 2.1.11 - 2.1.13).
Rice. 2.1.11. Topographic relationship between the eyeball and the soft tissues of the orbit (no Ducasse, 1997): a - horizontal section of the orbit (1 - optic nerve: 2 - external rectus muscle: 3 - internal rectus muscle; 4 - ethmoid sinus; 5 - fibrous bands to the outer wall of the orbit); b - sagittal section of the orbit (1 - eyeball; 2 - superior rectus muscle; 3 - superior orbital vein; 4 - inferior rectus muscle; 5 - inferior oblique muscle; 6 - frontal sinus; 7 - maxillary sinus; 8 - cerebral hemisphere) ; c - coronal section of the orbit (1 - eyeball; 2 - levator of the upper eyelid; 3 - superior rectus muscle; 4 - external rectus muscle; 5 - superior oblique muscle; 6 - ophthalmic artery; 7 - internal rectus muscle; 8 - inferior oblique muscle; 9 - lower rectus muscle; 10 - frontal sinus; 11 - air cavities of the ethmoid bone; 12 - maxillary sinus
Rice. 2.1.12. Horizontal section passing at the level of the edge of the eyelids: the superficial head of the internal ligament of the eyelid is not visible at this level, but the orbital septum is visible. The posterior fibers of Horner's muscle originate from the pretarsal part of the orbicularis oculi muscle, while the more anteriorly located fibers of the muscle attach to the preseptal part of the orbicularis muscle. (1 - lower rectus muscle; 2 - internal rectus muscle; 3 - external rectus muscle; 4 - restraining ("sentinel") ligament of the internal rectus muscle; 5 - orbital septum; 6 - Horner's muscle; 7 - lacrimal sac; 8 - lacrimal fascia; 9 - circular muscle of the eye; 10 - "cartilaginous" (tarsal) plate; 11 - fatty tissue; 12 - restraining ("sentinel") ligament of the external rectus muscle)
Rice. 2.1.13. The ratio of fascial membranes and fatty tissue to the muscle funnel (according to Parks, 1975): 1 - lower oblique muscle; 2 - intermuscular septum; 3 - fatty tissue located outside the muscle funnel; 4 - lower rectus muscle; 5 - external rectus muscle; 6 - zinn ring; 7 - levator of the upper eyelid; 8- upper straight muscle; 9 - fatty tissue located above the muscle funnel; 10 tenon capsule; 11 orbital septum; 12 conjunctiva; 13 orbital septum
Let's start the description with the tissue that covers the bony walls of the orbit.
Periosteum (periorbita). The bones of the orbit, like all bones in the body, are covered with a layer of fibrous tissue called the periosteum. It should be emphasized that the periosteum is not tightly fixed to the bone almost throughout its entire length. It is tightly attached only to the edges of the orbit, in the region of the upper and lower orbital fissures, as well as near the optic canal, lacrimal gland and lacrimal scallops. In other places, it is easily separated. This can occur both during surgery and in the post-traumatic period as a result of accumulation of exudate or transudate under the periosteum.
At the visual opening, the periosteum gives fibrous cords to the external muscles of the eye, as well as deep into the orbit, while dividing fatty tissue into lobules. It also envelops the vessels and nerves.
In the visual canal, the periosteum is combined with the endosteal layer of the dura mater.
The periosteum also covers the upper orbital fissure, with the exception of the passage of vessels and nerves.
Anteriorly, the periosteum covers the frontal, zygomatic, and nasal bones. Through the inferior orbital fissure, it spreads in the direction of the pterygoid and palatine bones and the temporal fossa.
The periosteum also lines the lacrimal fossa, forming the so-called lacrimal fascia, enveloping the lacrimal sac. At the same time, it spreads between the anterior and posterior lacrimal scallops.
The periosteum of the orbit is intensively supplied with blood vessels, which are extremely intensively anastomosing with each other, and is innervated by branches of the trigeminal nerve.
The periosteum is a dense fibrous tissue serves as a rather powerful obstacle to the spread of blood after an injury, inflammatory process, tumors emanating from the paranasal sinuses. However, it eventually collapses.
For coffee disease(infantile cortical hyperostosis) inflammation of the periosteum develops for an unknown reason, leading to proptosis and an increase in intraorbital pressure to such an extent that glaucoma develops. Granular cell sarcoma also originates from the periosteum. The periosteum may be the only barrier between the contents of the orbit and the dermoid cyst, the mucocele.
The potential space between the periorbita and the bones provides the possibility of a fairly complete removal of the tissues of the orbit in tumors. It must also be pointed out that the periosteum must be preserved as much as possible when removing tumors because it is an obstacle to its further distribution.
Fascia. The organization of the fibrous tissue of the orbit has traditionally been considered in terms of anatomy. Based on this, the fascia of the orbit is divided into three parts: the fascial membrane covering the eyeball (Tenon's capsule; fascia bitlbi), the membranes. covering the external muscles of the eye and "sentinel" ligaments, originating from the fascia of the external muscles of the eye and heading to the bones and eyelids (Fig. 2.1.12).
Thanks to the work of Koomneef, who used the methods of reconstructive anatomy (restoration of the volumetric arrangement of structures based on the analysis of serial sections), soft tissues eye sockets are currently considered as a complex biomechanical system that provides the mobility of the eyeball.
Vagina of the eyeball(Tenon's capsule; fascia bulbi) (Fig. 2.1.13, 2.1.14)
Rice. 2.1.14. Posterior part of the Tenon's capsule: The figure shows part of the Tenon's capsule of the right orbit after the removal of the eyeball (1 - conjunctiva; 2 - external rectus muscle; 3 - superior rectus muscle; 4 - optic nerve; 5 - superior oblique muscle; 6 - mouths of the meibomian glands; 7 - lacrimal opening; 8 internal rectus muscle, 9 - lacrimal meat; 10 - Tenon's capsule; 11 - lower oblique muscle; 12 - lower rectus muscle)
is a connective tissue membrane that begins in the region of the posterior part of the eye at the point of entry of the optic nerve and goes anteriorly, enveloping the eyeball. Its anterior margin fuses with the conjunctiva of the eye in the corneoscleral region.
Although the Tenon's capsule adheres closely to the eye, it can still be separated from it at a certain distance. At the same time, bridges of delicate fibrous tissue remain between the eyeball and the capsule. The resulting space is called the potential Tenon space.
Implants after enucleation of the eyeball are placed in the cavity of the Tenon capsule or somewhat back, within the muscle funnel.
Tenon's capsule is subject to various inflammatory processes. This occurs with pseudotumors of the orbit, scleritis and choroiditis. The inflammatory process often ends with fibrosis of the capsule.
Outside Tenon's capsule connects to the system of fibrous cords and layers, dividing the fatty tissue of the orbit into lobules (Fig. 2.3.12). The eye is thus tightly connected to the surrounding fatty tissue, but at the same time retains the ability to rotate in different planes. This is facilitated by the presence of elastic fibers in the connective tissue surrounding the Tenon's capsule.
Four muscles penetrate the Tenon's capsule (Fig. 2.3.14). This occurs approximately at a distance of 10 mm from the limbus. When passing through the Tenon's capsule, fibrous layers (intermuscular septa) depart into the muscle. Eyeball covered with Tenon's capsule just behind the insertion of the rectus muscles. Thus, in front of the place of attachment of the muscles to the eyeball, three tissue layers are found: the most superficial is the conjunctiva, then the Tenon's capsule, and the most internal is the intramuscular septum (septa). It is important for an ophthalmologist to remember these formations, especially during surgery on the muscles. In cases of dissection of the Tenon capsule at a distance of more than 10 mm from the limbus, the fatty tissue of the orbit bulges forward, leading to prolapse of the orbit.
Tenon's capsule forms a series of facies formations. In the horizontal plane, the capsule extends from the internal rectus muscle to the place of attachment to the periosteum of the zygomatic bone, and from the external rectus muscle to the lacrimal bone.
Between the superior rectus muscle and the levator aponeurosis of the upper eyelid there is also many fascial bands, which coordinate the movement of the eye and eyelid. If these connective tissue strands are removed, which happens during resection of the levator due to ptosis, hypotropia (downward strabismus) may develop.
The fascial membranes of the external muscles of the eye are thin, especially in the posterior regions. Anteriorly, they thicken considerably.
As indicated somewhat above, fibrous strands heading towards the walls of the orbit depart from the external muscles of the eye. As they move away from the muscles, they are more and more clearly identified as anatomical formations. These fibrous bands are called suspension ligaments. The most powerful are the ligaments that originate from the rectus muscles (internal and external) (Fig. 2.1.12, 2.1.15).
Rice. 2.1.15. Distribution of fascial membranes of the right eye socket (posterior view): 1 - the upper part of the fascia of the levator of the upper eyelid (the central part of the upper transverse ligament); 2 - common part of the fascia of the levator of the upper eyelid and the upper rectus muscle; 3-medial ligament of the lacrimal gland; 4 upper transverse ligament (together with 1 and 2); 5 - intermuscular membranes; 6 - lacrimal gland; 7 - lower transverse ligament; 8 - posterior lacrimal scallop, 9 - medial capsular ligament ("guard" ligament); 10 - lateral tubercle of the orbit (Whitnell's ligament); 11-lateral capsular ("sentinel") ligament; 12 - Tenon's capsule (back part); 13 - tendon of the superior oblique muscle and block
External suspensory ligament more powerful. It starts on the posterior surface of the lateral orbital eminence (Whitnell's tubercle) and goes towards the external fornix of the conjunctiva and the outer part of the orbital septum (Fig. 2.1.15).
Internal suspension ligament but originates somewhat behind the posterior lacrimal crest and goes to the lateral part of the orbital septum, the lacrimal caruncle and the semilunar fold of the conjunctiva.
Upper transverse Witnell's ligament many authors consider it as the upper suspension ligament.
Lockwood once described hammock-like structure extending under the eyeball from the inner wall of the orbit to the outer wall. It is formed by the fusion of the fasciae of the inferior rectus and inferior oblique muscles. This ligament can support the eye even after removal of the maxilla and orbital floor. It is more powerful in front of the inferior oblique muscle.
In the fascial membrane of all the external muscles of the eye, you can find a different amount smooth muscle fibers. Most of all they are in the fascia of the upper and lower rectus muscles.
The dense connective tissue surrounding the external muscles of the eye forms a funnel, the top of which is located in the zinn ring. The anterior border of the infundibulum lies at a distance of 1 mm from the point of attachment of the external muscles of the eye to the sclera.
All strands of fibrous tissue of the orbit, including fibrous layers of lobules of adipose tissue, belong to the fascicular system of the orbit. This dense connective tissue may undergo a pathological lesion such as fasciitis nodosum, an inflammatory pseudotumor.
For more information about the fascial formations of the orbit, see the section on the description of the external muscles of the eye.
Fatty tissue of the orbit. All spaces of the orbit that do not contain the eyeball, fascia, nerves, blood vessels or glandular structures are filled with adipose tissue (Fig. 2.1.11). Adipose tissue is, as it were, a shock absorber for the eyeball and other structures of the orbit.
In the anterior part of the orbit, fibrous connective tissue predominates in fatty tissue, while in the posterior parts, fatty lobules predominate.
The fatty tissue of the orbit is divided by the connective tissue septa into two parts - central and peripheral. Central part lies in the muscle funnel. In its anterior part, it is bounded by the posterior surface of the eye, covered with a Tenon's capsule. peripheral part of the fatty tissue of the orbit is limited by the periosteum of the walls of the orbit and the orbital septum.
When opening the orbital septum in the region of the upper eyelid, right in the center is visible preaponeurotic fat pad. Inside and below the block is the inner fat pad of the upper eyelid. It is lighter and denser. In the same area is the subtrochlear nerve (n. intratrochlearis) and the terminal branch of the ophthalmic artery.
The main cellular component of the fat lobules is lipocyte, the cytoplasm of which is made of neutral free and bound fats. Clusters of lipocytes are surrounded connective tissue containing numerous blood vessels.
Despite the presence of a large amount of adipose tissue, tumors in the orbit, the source of which can be adipose tissue, are extremely rare (lipoma, liposarcoma). It is assumed that orbital liposarcoma generally develops not from lipocytes, but from ectomesenchyme cells.
Most often, adipose tissue is involved in the development inflammatory pseudotumors of the orbit, being its structural component. As the disease progresses, lipocytes are destroyed, releasing free lipids. Free, extracellularly located lipids in turn increase the inflammatory process, causing a granulomatous reaction. This inflammatory process is completed by fibrosis of the affected and surrounding tissues. This condition is rated as lipogranuloma. The development of lipogranuloma can lead to trauma to the orbit, accompanied by necrosis of fatty tissue.
Almost all pathological processes of a granulomatous nature (mycoses, Wegener's granulomatosis, etc.) include adipose tissue.
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eye socket, or orbit, orbita, is a paired four-sided cavity, cavitas orbitalis (LNA), resembling a pyramid, which contains the organ of vision. It has an entrance to the orbit, aditus orbitalis, which is limited by the orbital margin, margo orbitalis. The depth of the orbit in an adult is from 4 to 5 cm, the width is about 4 cm. It is important to take this into account in clinical practice when probing the wounds of the orbit, inserting a needle during injections. The orbit is limited by four walls: upper, lower, medial and lateral, lined with periosteum, periorbita. Top wall, paries superior, is formed by the orbital surface of the frontal bone and the lesser wing of the sphenoid bone. It separates the orbit from the anterior cranial fossa and the brain. bottom wall, paries inferior, is formed by the orbital surface of the upper jaw, the zygomatic bone and the orbital process of the palatine bone. The lower wall is the roof of the maxillary sinus (maxillary sinus), which should be considered in clinical practice. medial wall, paries medialis, formed by the frontal process of the upper jaw, the lacrimal bone, the orbital plate of the ethmoid bone, the body of the sphenoid bone and partially the orbital surface of the frontal. The medial wall is thin and has a number of openings for the passage of blood vessels and nerves. This circumstance easily explains the penetration of pathological processes from the lattice cells into the orbit and vice versa. Lateral wall, paries lateralis, is formed by the orbital surface of the zygomatic bone and the greater wing of the sphenoid bone, as well as the ophthalmic part of the frontal bone. It separates the orbit from the temporal. In the orbit, we observe a number of holes and crevices, with the help of which it is combined with other formations of the skull: the optic nerve canal, canalis opticus, lower orbital fissure, fissura orbitalis inferior, superior orbital fissure; fissura orbitalis superior, zygomatic-orbital foramen, foramen zygomaticoorbitale; nasolacrimal canal, canalis nasolacrimalis, anterior and posterior ethmoid openings, foramen ethmoidalis anterior et posterior. In the depths of the orbit, on the border between the upper and lateral walls, there is a gap in the form of a comma (superior orbital fissure, fissura orbitalis superior), formed by the body of the sphenoid bone, its large and small wings. It connects the orbit to the cranial cavity (middle cranial fossa). All the motor nerves of the eyeball pass through the superior orbital fissure: oculomotor, n. oculomotorus, blocky, n. trochlearis, efferent, n. abducens, and optic nerve, n. ophthalmicus, and the main venous collector of the orbit (superior ophthalmic vein, v. ophthalmica superior). The concentration within the upper orbital fissure of a number of important formations explains in the clinic the occurrence of a peculiar symptom complex, which, when this area is affected, is called the syndrome of the superior orbital fissure. On the border between the lateral and lower walls of the orbit passes the lower orbital fissure, fissura orbitalis inferior. It is limited by the lower edge of the large wing of the sphenoid bone and the body of the upper jaw. In the anterior part, the gap connects the orbit with the infratemporal, and in the back - with the pterygopalatine fossa. Venous anastomoses pass through the inferior orbital fissure, connecting the veins of the orbit with the venous plexus of the pterygopalatine fossa and the deep vein of the face, v. facialis profunda.
On the inner wall of the orbits there are anterior and posterior ethmoid openings, which serve to pass the nerves, arteries and veins of the same name from the orbits to the labyrinths of the ethmoid bone and the nasal cavity. In the thickness of the lower wall of the orbits lies the infraorbital sulcus, sulcus infraorbitalis, passing anteriorly into the canal of the same name, which opens on the front surface with a corresponding opening, foramen infraorbitale. This channel serves for the passage of the inferoorbital nerve with the same artery and vein.
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The eyeball is located in the bone receptacle - the eye socket (orbita). The eye socket has the shape of a truncated tetrahedral pyramid, the top of which is turned towards the skull. The depth of the orbit in adults is 4-5 cm, the horizontal diameter at the entrance to the orbit (aditus orbitae) is about 4 cm, and the vertical diameter is 3.5 cm.
The orbit has four walls (upper, lower, outer and inner), three of which (inner, upper and lower) border on the paranasal sinuses.
bottom wall formed by the zygomatic bone, the orbital surface of the upper jaw and the orbital process of the palatine bone (Fig. 1). The bottom wall covers maxillary sinus, inflammatory processes which can quickly spread to the tissues of the orbit. The lower wall is most often subjected to blunt trauma (contusion); as a result, a downward displacement of the eyeball may occur, limiting its mobility upwards and outwards when the inferior oblique muscle (m. obliquus inferior) is infringed.
Top wall formed by the frontal bone, in the thickness of which there is a sinus (sinus frontalis), and a small wing of the sphenoid bone. On the frontal bone from the side of the orbit, at the outer edge, there is a small bone protrusion (spina trochlearis), to which the tendon (cartilaginous) loop is fixed, the tendon of the superior oblique muscle (lig. m, obliqui superioris) passes through it. In the frontal bone above and outside there is a fossa of the lacrimal gland (fossa glandulae lacrimalis). The upper wall of the orbit is located on the border with the anterior cranial fossa, which is very important to consider in case of injuries.
Inner wall formed: from below - by the upper jaw and palatine bone; from above - part of the frontal bone; behind - the sphenoid bone; in front - the lacrimal bone and the frontal process of the upper jaw.
In the lacrimal bone there is a posterior lacrimal crest, in the frontal process of the upper jaw there is an anterior lacrimal crest. Between them is a recess - the fossa of the lacrimal sac (fossa sacci lacrimalis), in which the lacrimal sac (saccus lacrimalis) is located. Hole size 7x13 mm; below, it passes into the nasolacrimal duct (ductus nasolacrimalis) 10-12 mm long, which runs in the wall of the maxillary bone and ends 2 cm posterior to the anterior edge of the inferior turbinate. If the wall is damaged, emphysema of the eyelids and orbits develops.
The inner, upper and lower walls of the orbit border on the paranasal sinuses, which often causes the spread of inflammation and the tumor process from them into the orbital cavity.
outer wall- the most durable; it is formed by the zygomatic, frontal bone and the greater wing of the sphenoid bone.
In the walls of the orbit near its apex there are openings and fissures through which large nerves and blood vessels 5–6 mm long pass into the orbital cavity (see Fig. 1).
Rice. 1. The structure of the eye socket
visual channel(canalis opticus) - a bone canal with a round hole with a diameter of 4 mm. Through it, the eye socket communicates with the cranial cavity. The optic nerve (n. opticus) and the ophthalmic artery (a. ophtalmica) pass through the optic canal.
Superior orbital fissure(fissura orbitalis superior) is formed by the body of the sphenoid bone and its wings. Through it, the orbit is connected to the middle cranial fossa. The gap is closed only by a thin connective tissue membrane through which three branches of the optic nerve (n. ophtalmicus) pass - n. lacrimalis, n. nasoclliaris, n. frontalis, as well as the oculomotor nerve (n. oculomotorius); the superior ophthalmic vein (v. ophtalmica superior) emerges from the orbit through this fissure. When the upper orbital fissure is damaged, the same complex of symptoms develops: complete ophthalmoplegia (lack of eyeball movement), ptosis (drooping of the upper eyelid), mydriasis (pupil dilation), tactile sensitivity disorder, retinal vein dilatation, exophthalmos (protrusion of the eyeball).
Inferior orbital fissure(fissura orbitalis inferior) is formed by the lower edge of the large wing of the sphenoid bone and the body of the upper jaw. Through it, the orbit communicates with the pterygopalatine and temporal fossa. The gap is closed by a connective tissue membrane, into which the fibers of the orbital muscle (m. Orbitalis) are woven, innervated by sympathetic nerve fibers. One of the two branches of the inferior ophthalmic vein (v. ophtalrmca interios) exits through this gap, and enters the orbit n. infraorbitalis and a. infraorbitalis, n. zygomaticus and rr. orbitalis from the pterygopalatine node (gangl. pterygopalatinum).
Front and rear grille openings(foramen ethmoidale anterius et posterius) - holes in the lattice plates. Through them pass the nerves of the same name, arteries and veins (branches of the nasociliary nerve).
oval hole(foramen ovale) is located in the greater wing of the sphenoid bone, connecting the middle cranial fossa with the infratemporal fossa. The mandibular nerve passes through it - n. n.andibularis (III branch of n. trigeminis).
On the inside, the orbit is covered with a periosteum (periorbita), which is tightly fused with the bones that form it in the canalis opticus region. Here is the tendon ring (annulus tendineus communis Zinni), in which all the oculomotor muscles begin, except for the inferior oblique.
To the fascia of the orbit in addition to the periosteum include:
- vagina of the eyeball (vag. bulbi);
- muscular fasciae (fasciae musculares);
- orbital septum (septum orbitale);
- fatty body of the orbit (corpus adiposum orbitae).
Vagina of the eyeball(vagina bulbi s. Tenoni) covers the entire eyeball, except for the cornea and exit site n. opticus. Its thickest part (2.5-3.0 mm) is located in the region of the equator of the eye, where the tendons pass oculomotor muscles, which acquire here a dense connective tissue sheath. Dense strands also depart from the equatorial zone, connecting the Tenon capsule with the periosteum of the walls and the edges of the orbit, thus creating a membrane that fixes the eyeball in the orbit. Below the eyeball is the suspensory ligament of Lockwood, which is of great importance in keeping the eyeball in the correct position during its movement.
Episcleral (Tenon's) space(spatium episclerale) is represented by loose episcleral tissue (this circumstance is often used for instillation of drugs, implantation of transposition materials for therapeutic purposes).
The orbital septum (septum orbitae) is the fifth movable wall of the orbit, which limits the cavity of the orbit when the eyelids close. It is formed by fasciae that connect the orbital edges of the cartilage of the eyelids with the bony edges of the orbit. The cavity of the orbit is filled with a fatty body; it is separated from the periosteum by a slit-like space. Vessels and nerves pass through the orbit from the apex to its base.
blood supply
The ophthalmic artery (a. ophtalmica) enters the orbit through the optic opening (foramen optidum) and immediately splits into several branches:
- central retinal artery (a. centralis retinae);
- supraorbital artery (a. supraorbitalis);
- lacrimal artery (a. lacrimalis);
- anterior and posterior ethmoid arteries (aa. ethmoidalis anterior et posterior);
- frontal artery (a. frontalis);
- short and longer posterior ciliary arteries (aa. ciliares posteriores breves et longae);
- muscular arteries (aa. musculares).
