How is the superior orbital fissure limited? Structure of the eye socket
Superior orbital fissure, connecting the orbit with the cranial cavity, is located between the upper and outer walls of the orbit, latsral to the optic nerve canal. Its size is 3x22 mm. It is divided into upper, or lateral, and lower, or medial, parts by two tendons of the extraocular muscles.
Through it they enter the orbit optic and oculomotor nerves. The first within the fissure is divided into three branches: the lacrimal and frontal nerves are located in the lateral part of the fissure, the nasociliary nerve passes through its medial part. The trochlear nerve is located medial to the frontal.
Oculomotor nerve within the gap it is also divided into two branches: the upper one, located between the trochlear and nasociliary nerves, and the lower one, passing at the medial edge of the gap. The superior ophthalmic and sometimes the inferior ophthalmic veins exit through the superior orbital fissure: the first - from the orbit through the upper part, the second - through the lower.
Gap covered with a connective tissue membrane - a very non-destructive protection during the spread of a tumor or inflammatory process in both directions.
Inferior orbital fissure located between the lower and outer walls at a distance of 10 mm (options from 2 to 12 mm are possible) from the outer orbital edge. It connects the orbit with the pterygopalatine and infratemporal fossae. With malignant tumors of the orbit, early spread of the process to both the pterygopalatine and temporal fossa is possible, which is extremely important to take into account when planning treatment and performing orbital exenteration.
Through inferior orbital fissure The infraorbital artery and the nerve of the same name pass through, and also enter the zygomatic nerve, perforating the periorbita. The inferior orbital fissure is the gateway to the anastomosis of the orbital venous system with the venous plexuses of the pterygopalatine fossa and the deep vein of the face. These features are important, especially during the surgical treatment of phlegmon and orbital abscesses.
Periorbita it is firmly connected to the underlying walls of the orbit only in the area of the bone sutures and along the edges of the natural openings; throughout the rest of its length it is adjacent to the walls, forming a slit-like subperiosteal space. Naturally, during orbital operations, if manipulations in the noperiosteal space are necessary, the surgeon must remember the places of close contact of the periorbita and adjacent bones.
Bone volume orbits on average is 23 cm3 in women and 26 cm3 in men, 80% of the volume is occupied by the neuromuscular system, blood vessels, fatty tissue and only 20% by the eye itself. Studying Pirogov sections, P.I. Kolesnikov determined the distance of the eye from the walls of the orbit: from the upper wall - by 6.7 mm, from the outer wall - by 6.3, from the bottom - by 9.5, from the inner wall - by 9 mm. It would seem that the significant distance of the eye from the upper and inner walls of the orbit makes these zones more accessible for palpation examination of the retrobulbar space.
However, in the upper section it difficult due to an overhanging superior orbital rim (concave position of the superior orbital wall).
The lower section is more accessible to palpation orbits, since the concavity of the lower wall of the orbit is much less. In front, starting from the orbital edge, merging along the edge with the periosteum, there is the fifth “wall” of the orbit - the tarso-orbital fascia (septum orbitae), which in the eyelid area is woven into the edge of the cartilage of the upper and lower eyelids. Thus, the orbital cavity includes everything that lies behind the tarso-orbital fascia.
It is important to know the anatomy of the orbit and its dimensions in order to correctly produce instrumental examination and treat diseases by injection. With injuries to the bone cavity, there is a high probability of an abscess and other diseases that can spread to the brain.
Structure
The orbit is formed by four walls - outer, inner, upper and lower. They are tightly connected to each other. The total volume of the orbit is up to 30 ml, 5 ml of this space is occupied by the eyeball.
The orbital cavity may change with age. In children it is smaller in size, increasing as the bones grow.
Other structures of the bony orbit:
- eyeball;
- nerve endings;
- vessels;
- muscle joints, ligaments;
- fatty tissue.
The standard dimensions of the skull orbit are 4.0x3.5x5.5 cm (width-height-depth).
The anatomical formations of the orbit of the skull include:
- lacrimal fossa;
- nasolacrimal duct;
- supraorbital notch;
- infraorbital groove;
- side spike;
- eye slits.
Holes and crevices
There are openings in the walls of the orbit through which nerve endings and blood vessels pass:
- Lattice. Located between the top and inner walls. The nasociliary veins, arteries and nerves pass through them.
- Oval hole. Located in the sphenoid bone, it is the entrance to the third branch trigeminal nerve.
- Round hole. It is the entrance to the second branch of the trigeminal nerve.
- Optic or bony canal. Its length is up to 6 mm, and the optic nerve and ophthalmic artery pass through it. Connects the cranial fossa and the orbit.
In the depths of the orbit there are fissures: the superior and inferior orbital. The first is covered by a connective film through which the frontal, lacrimal, nasociliary, trochlear, abducens and oculomotor nerves pass. The superior ophthalmic vein also emerges.
The inferior orbital fissure is covered by a connecting septum, which serves as a barrier to infections. It performs an important function - draining blood from the eye. The inferior ophthalmic vein, the inferior orbital and zygomatic nerves, and branches of the pterygopalatine nerve ganglion pass through it.
Walls and partitions
- Outer wall. It is the most durable and is rarely damaged by injury. Formed by the sphenoid, zygomatic and frontal bones.
- Internal. This is the most fragile partition. It is damaged even with blunt trauma, causing emphysema (air in the orbit of the skull) to develop. The wall is formed by the ethmoid bone. There is a depression called the lacrimal fossa or lacrimal sac.
- Upper. Formed by the frontal bone, a small portion of the posterior part consists of the sphenoid bone. There is a fossa where the lacrimal gland is located. In the anterior region of the septum there is the frontal sinus, which is a hotbed for the spread of infection.
- Bottom. Formed by the upper jaw and zygomatic bone. The inferior septum is a segment of the maxillary sinus. With injuries and bone fractures, the eyeball drops and the oblique muscles become pinched. It is impossible to move the eye up and down.
All septa, except the lower one, are located near the paranasal sinuses and are therefore susceptible to infection. There is a high probability of tumor growth.
Physiological functions
The orbit of the skull performs the following functions:
- protecting the eyeball from damage, maintaining its integrity;
- connection with the middle cranial fossa;
- preventing the development of infection and inflammatory process on the organs of vision.
Common diseases and their symptoms
Symptoms occur due to tumor and inflammatory processes, injuries, damage to blood vessels or the optic nerve.
The most common symptom of disease of the bone orbit of the skull is a violation of the dislocation of the eyeball in the orbit.
It comes in three types:
- exophthalmos (protrusion);
- enophthalmos (retraction);
- violation of the position down or up.
With inflammation, cancer of the orbit, or injury to it, visual acuity decreases (even to the point of blindness). The mobility of the eyeball is also impaired, its location in the orbit may change, and the eyelids swell and turn red.
Symptoms of damage to the superior palpebral fissure:
- omission upper eyelid;
- pupil dilation;
- complete immobility of the eyeball;
- exophthalmos.
If the outflow of blood in the superior ophthalmic vein is impaired, then dilation of the veins of the eye is noticeable.
Diagnostic methods
The examination involves a visual inspection of the location of the eyeball in the orbit; the ophthalmologist palpates the outer walls.
To clarify the diagnosis, exophthalmometry (a method for assessing the deviation of the eye forward or backward), ultrasound or x-ray of musculoskeletal tissue is performed. If cancer is suspected, a biopsy is performed.
The orbit is an important component of the visual organ system. Despite the fact that this is a bone formation, it contains nerve fibers, muscle tissue, and blood vessels that can give way various diseases. All orbital diseases must be diagnosed and treated in a timely manner.
Useful video about the structure of the eye socket
17-09-2012, 16:51
Description
Eye socket shape
The eye socket contains
- eyeball,
- external muscles of the eye,
- nerves and blood vessels,
- fatty tissue, with
- useful 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 optic opening is slightly covered by the medial wall of the orbit. The left optic foramen is slightly visible as a small depression (small arrow). The large arrow points to the superior orbital 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 - frontosphenoid process of the zygomatic bone: 4 - orbital surface of the greater 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 hole; 10 - supraorbital notch; 11 - trochlear fossa; 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 - inferior orbital groove; 20 infraorbital fissure; 21-zygomaticofacial foramen; 22-superiorbital 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 equal to half 45°, i.e. 22.5° (Fig. 2.1.2).
Linear and volumetric dimensions of the orbit fluctuate different people within a fairly wide range. However, the average values are as follows. The widest part of the orbit is located at a distance of 1 cm from its anterior edge and is equal to 40 mm. The greatest height is approximately 35 mm, and the depth is 45 mm. Thus, in an adult, the volume of the orbit 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 (os sphenoidale)
- and zygomatic bone (os zigomaticum).
Orbital edges
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 is formed by 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 the sutures. In this case, the fracture occurs either along the line of the zygomatic-maxillary suture in a downward direction or downward-outward along the line of the zygomatic-frontal suture. The direction of the fracture depends on the location of the traumatic force.
Frontal bone forms the upper edge of the orbit (margo siipraorbitalis), and its outer and inner parts participate in the formation of the outer and inner edges of the orbit, respectively. In newborns, the upper edge is sharp. It remains acute in women throughout life, and in men it rounds off with age. On the upper edge of the orbit on the medial side, the supraorbital recess (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 the spongy part of the bone.
Inner edge of the orbit(margo medialis orbitae) in the anterior sections is formed by the maxillary bone, which gives off a process to the frontal bone.
The configuration of the inner edge of the orbit is complicated by the presence in this area tear combs. For this reason, Whitnall suggests considering the shape of the inner edge as a wavy spiral (Fig. 2.1.3).
Lower edge of the orbit(margo inferior orbitae) is formed half by the maxillary and half by the zygomatic bones. Through the lower edge of the orbit with inside pass the infraorbital nerve (n. infraorbitalis) and the artery of the same name. They exit onto the surface of the skull through the infraorbital foramen (foramen infraorbitalis), located somewhat inward and below the lower edge of the orbit.
Bones, walls and openings of the orbit
As stated above, the orbit is formed by only seven bones, which also participate 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 The orbit is separated from the middle cranial fossa in the back and from the temporal fossa in the front. The orbit is located directly under the anterior cranial fossa and above the maxillary sinus.
Superior wall of the orbit (Paries superior orbitae)(Fig. 2.1.4).
Rice. 2.1.4. Superior wall of the orbit (according to Reeh et, al., 1981): 1 - orbital wall of the frontal bone; 2- fossa of the lacrimal gland; 3 - anterior ethmoidal opening; 4 - large wing of the sphenoid bone; 5 - superior orbital fissure; 6 - lateral orbital tubercle; 7 - trochlear fossa; 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 the anterior cranial fossa. It is formed by the orbital part of the frontal bone, and posteriorly by the small wing of the sphenoid bone. The sphenofrontal suture (sutura sphenofrontalis) runs between these bones.
On the upper wall of the orbit there is a large number of formations that play the role of “tags”, used during surgical interventions. In the anterolateral part of the frontal bone there is a fossa of the lacrimal gland (fossa glandulae lacrimalis). The fossa contains not only the lacrimal gland, but also a small amount of fatty tissue, mainly in the posterior part (accessory fossa Pout of Dovigneau (Roch on-Duvigneaud)). From below, the fossa is limited by the zygomaticofrontal suture (s. frontozigomatica).
The surface of the bone in the area of the lacrimal fossa is usually smooth, but sometimes roughness is detected at the site of attachment of the suspensory ligament of the lacrimal gland.
In the anteromedial part, approximately 5 mm from the edge, there are 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 apex of the orbit, directly at the lesser wing of the sphenoid bone, there is optic hole- entrance to the optic canal (canalis opticus).
The upper wall of the orbit is thin and fragile. It thickens to 3 mm at the site where it is formed by the small wing of the sphenoid bone (ala minor os sphenoidale).
The greatest thinning of the wall is observed in cases where the frontal sinus is extremely developed. Sometimes, with age, resorption of the bone tissue of the upper wall occurs. In this case, the periorbita is in contact with the hard meninges anterior cranial fossa.
Since the upper wall is thin, it is in this area Trauma causes a bone fracture with the formation of sharp bone fragments. Through the upper wall, various pathological processes (inflammation, tumors) developing in the frontal sinus spread into the orbit. It is also 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.
Inner wall of the orbit (Paries Мedialis orbitae)(Fig. 2.1.5).
Rice. 2.1.5. Inner wall of the orbit (after Reeh et al, 1981): 1 - anterior lacrimal ridge and frontal process of the maxilla; 2- lacrimal fossa; 3 - posterior lacrimal ridge; 4- lamina rarugasea of the ethmoid bone; 5 - anterior ethmoidal opening; 6-optic foramen and canal, superior orbital fissure and spina recti lateralis; 7 - lateral angular process of the frontal bone: 8 - lower orbital margin with the zygomaticofacial foramen 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 maxilla (processus frontalis os zigomaticum),
- lacrimal bone
- and the lateral orbital surface of the sphenoid bone (fades orbitalis os sphenoidalis), located most deeply.
Visible in front of the inner wall tear trough(sulcus lacrimalis), continuing into the fossa of the lacrimal sac (fossa sacci lacrimalis). It contains the lacrimal sac. As it moves downwards, the lacrimal groove passes into the nasolacrimal canal (capalis nasolacrimalis).
The boundaries of the lacrimal fossa are outlined by two ridges - anterior and posterior lacrimal ridges(crista lacrimalis anterior et posterior). The anterior lacrimal ridge continues downwards and gradually passes into the lower edge of the orbit.
The anterior lacrimal ridge is easily palpable through the skin and is a mark during operations on the lacrimal sac.
As indicated 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 tissue of the orbit. This can lead to the development of cellulite, orbital phlegmon, thrombophlebitis of the orbital veins, toxic optic neuritis, etc. Children often experience acutely developing ptosis. The inner wall is also where tumors spread from the sinus to the orbit and vice versa. It is often destroyed during surgical interventions.
The inner wall is somewhat thicker only in the posterior sections, especially in the area of the body of the sphenoid bone, as well as in the area of the posterior lacrimal crest.
Ethmoid bone, participating in the formation of the internal 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 floor of the orbit.
It is also necessary to mention that in the area of the lattice seam there are often abnormalities in the development of bone walls, for example, congenital “gaping,” which significantly weakens the wall. In this case, the bone tissue defect is covered with fibrous tissue. Weakening of the inner wall also occurs with age. The reason for this is atrophy of the central areas 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 pass, as well as the branches of the nasociliary nerve.
The anterior ethmoidal openings open at the anterior end of the frontoethmoidal suture, and the posterior ones - near the posterior end of the same suture (Fig. 2.1.5). Thus, the anterior openings lie at a distance of 20 mm behind the anterior lacrimal ridge, and the posterior ones at a distance of 35 mm.
Located deep in the orbit on the inner wall visual channel(canalis opticus), connecting the orbital cavity with the cranial cavity.
Outer wall of the orbit (Paries lateralis orbitae)(Fig. 2.1.6).
Rice. 2.1.6. Outer wall of the orbit (according to Reeh et al, 1981): 1 - frontal bone; 2 - large wing of the sphenoid bone; 3 - zygomatic bone; 4 - superior orbital fissure; 5 - spina recti lateralis; 6 - inferior orbital fissure; 7 - hole through which the branch passes from the zygomatic-orbital nerve to the lacrimal gland; 8 - zygomaticoorbital foramen
The outer wall of the orbit in its posterior section separates the contents of the orbit and middle cranial fossa. In front it borders with the temporal fossa (fossa temporalis), made by the temporal muscle (t. temporalis). It is delimited from the upper and lower walls by orbital fissures. These boundaries extend anteriorly to the sphenoid-frontal (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 is the orbital surface of the zygomatic bone. Between them is the sphenoid-zygomatic suture (sutura sphenozigomatica). The presence of this suture greatly simplifies orbitotomy.
On the body of the sphenoid bone, at the junction of the wide and narrow parts of the superior orbital fissure, there is small bony prominence(spike) (spina recti lateralis), from which the external rectus muscle begins.
On the zygomatic bone near the edge of the orbit is located zygomaticoorbital foramen(i. zigomaticoorbitale), through which the branch of the zygomatic nerve (n. zigomatico-orbitalis) leaves the orbit, heading to the lacrimal nerve. In the same area, the orbital eminence (eminentia orbitalis; orbital tubercle of Withnell) is also found. The external ligament of the eyelid, the external “horn” of the levator, Lockwood’s ligament (lig. suspensorium), orbital septum (septum orbitale) and lacrimal fascia (/. lacrimalis) are attached to it.
The outer wall of the orbit is the place of easiest access to the contents of the orbit during various surgical interventions. The spread of the pathological process to the orbit on 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 distant from the middle cranial fossa at a distance of 12-13 mm in men and 7-8 mm in women.
Lower wall of the orbit (Paries inferior orbitae)(Fig. 2.1.7).
Rice. 2.1.7. Lower 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 - inferior orbital groove; 5 - orbital surface of the greater wing of the sphenoid bone; 6 - marginal process of the zygomatic bone; 7 - lacrimal fossa; 8 - inferior orbital fissure; 9 - origin of the inferior oblique muscle
The bottom of the orbit is also the roof of the maxillary sinus. This proximity is important from a practical point of view, since diseases of the maxillary sinus often affect the orbit and vice versa.
Inferior wall of the orbit formed by three bones:
- orbital surface of the upper jaw (fades orbitalis os maxilla), occupying most of the floor of the orbit,
- zygomatic bone (os zigomaticus)
- 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) there is inferior orbital fissure(fissura orbitalis inferior). A 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 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 it moves forward, turns into a canal (canalis infraorbitalis). They contain the infraorbital nerve (p. 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. The inside wall becomes noticeably thinner. It is in these places that post-traumatic fractures are localized. The lower wall is also the site of spread of inflammatory and tumor processes.
Optic canal (Canalis opticus)(Fig. 2.1.3, 2.1.5, 2.1.8).
Rice. 2.1.8. Apex of the orbit (according to Zide, Jelks, 1985): 1 - inferior orbital fissure; 2- round hole; 3- superior orbital fissure; 4-optic foramen and optic canal
The optic foramen is located slightly inward of the superior orbital fissure, which is the beginning of the optic canal. The optic foramen is separated from the superior orbital fissure by the area connecting 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 plane (Fig. 2.1.3, 2.1.5, 2.1.8).
Visual channel leads to the 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°.
Through the canal pass the optic nerve (n. opticus), the ophthalmic artery (a. ophtalmica), immersed in the optic nerve sheath, as well as the trunks of the sympathetic nerves. After entering the orbit, the artery lies below the nerve, and then crosses the nerve and is located outside.
Since in embryonic period The position of the ophthalmic artery changes, the canal takes the form of a horizontal oval in the posterior section and a vertical oval in the anterior section.
By the age of three, the visual canal reaches normal size. Its diameter of more than 7 mm must already be considered a deviation from the norm and the presence of a pathological process must be assumed. A significant increase in the optic canal 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 its final size. If a different diameter of the optic canals is detected (at least 1 mm), we can fairly 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, most often found optic nerve gliomas, aneurysms in the sphenoid bone area, 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 expansion of the optic canal. This is benign hyperplasia of the arachnoid membrane, fungal infections(mycoses), granulomatous inflammatory reaction(syphilitic gumma, tuberculoma). Dilation of the canal also occurs with sarcoidosis, neurofibroma, arachnoiditis, arachnoid cyst and chronic hydrocephalus.
Narrowing of the canal is possible with fibrous dysplasia or fibroma of the sphenoid bone.
Superior orbital fissure (Fissura orbitalis superior).
Shape and size of the superior orbital fissure vary significantly between individuals. It is located on the outside of the optic opening at the apex 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 superior orbital fissure and ring of Zinn (according to Zide, Jelks, 1985): 1 - external rectus muscle; 2-superior and inferior branches of the oculomotor nerve; 3- frontal nerve; 4- lacrimal nerve; 5 - trochlear nerve; 6 - superior rectus muscle; 7 - nasociliary nerve; 8 - levator of the upper eyelid; 9 - superior oblique muscle; 10 - abducens nerve; 11 - internal rectus muscle; 12 - inferior 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 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,
- superior orbital vein,
- recurrent lacrimal artery,
- sympathetic root of the ciliary ganglion (Fig. 2.1.9).
Common tendon ring(anulus tendineus communis; ring of Zinn) is located between the superior orbital fissure and the optic canal. Through the ring of Zinn, the optic nerve, ophthalmic artery, superior and inferior branches of the trigeminal nerve, nasociliary nerve, abducens nerve, sympathetic roots of the trigeminal ganglion enter the orbit and are thereby located in the muscular funnel (Fig. 2.1.8, 2.1.9).
Immediately below the ring in the superior orbital fissure passes superior branch of the inferior ophthalmic vein(v. ophthalmica inferior). Outside the ring on the lateral side of the superior orbital fissure there are trochlear nerve(n. trochlearis), superior ophthalmic vein (v. ophthalmica superior), as well as lacrimal and frontal nerves (nn. lacrimalis et frontalis).
Widening 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 unknown nature develops in the area of the superior orbital fissure (Talasa-Hant syndrome, painful ophthalmoplegia). Inflammation may spread to the nerve trunks leading to the external muscles of the eye, which is the cause of the pain that occurs with this syndrome.
The inflammatory process in the area of the superior orbital fissure can lead to violation of venous drainage of the orbit. The consequence of this is swelling of the eyelids and eye sockets. Tuberculous encephalic periostitis, spreading to structures located in the intraorbital fissure, has also been described.
Inferior orbital fissure (Fissura orbitalis inferior)(Fig. 2.1.7-2.1.10).
Rice. 2.1.10. Temporal, infratemporal and pterygopalatine fossa: 1 - temporal fossa; 2-pterygopalatine fossa; 3 - oval hole; 4 - pterygopalatine foramen; 5 - inferior orbital 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. Externally, it is limited by the greater 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 optic foramen and lies at a level corresponding to the lower edge of the orbit.
The inferior orbital fissure extends forward more than the superior orbital fissure. It ends at a distance of 20 mm from the edge of the orbit. It is this point that is the landmark of the posterior border when performing subperiosteal removal of the bone of the lower wall of the orbit.
Directly below the inferior orbital fissure and on the outside 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 lower orbital fissure in the large wing of the main bone is located round hole(foramen rotundum), connecting the middle cranial fossa with the pterygopalatine fossa. Through this hole, branches of the trigeminal nerve penetrate into the orbit, in particular the maxillary nerve (n. maxillaris). When leaving the foramen, the maxillary nerve gives off a branch - infraorbital nerve(n. infraorbitalis), which, together with the infraorbital artery (a. infraorbitalis), penetrates 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 onto the facial surface of the maxillary bone at a distance of 4-12 mm below the middle of the edge of the orbit.
Through the inferior orbital fissure from the infratemporal fossa (fossa infratemporalis) the orbit also penetrates zygomatic nerve(n. zigomaticus), small branch of the pterygopalatine ganglion (gangsphenopalatina) and veins (inferior ophthalmic), draining blood from the orbit to the pterygoid plexus (plexus pterygoideus).
In the orbit, the zygomatic nerve divides into two branches- zygomatico-facial (zigomaticofacialis) and zygomaticotemporal (p. 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 in the skin of the zygomatic and temporal regions. A nerve trunk carrying secretory fibers separates from the zygomaticotemporal nerve towards the lacrimal gland.
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 orbit
Having outlined the basic information regarding the bone formations of the orbit, it is necessary to focus on its contents. The contents of the orbit are a complex set of anatomical formations that have different functional significance and belong to different tissues both in origin and 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 cords 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 muscle; 9 - lower rectus muscle; 10 - frontal sinus; 11 - air spaces of the ethmoid bone;
Rice. 2.1.12. Horizontal section passing at the level of the eyelid margin: 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 arise from the pretarsal portion of the orbicularis oculi muscle, while the more anterior fibers of the muscle insert into the preseptal portion of the orbicularis oculi muscle. (1 - inferior rectus muscle; 2 - internal rectus muscle; 3 - external rectus muscle; 4 - retaining (“sentinel”) ligament of the internal rectus muscle; 5 - orbital septum; 6 - Horner’s muscle; 7 - lacrimal sac; 8 - lacrimal fascia; 9 - orbicularis oculi muscle; 10 - “cartilaginous” (tarsal) plate; 12 - retaining (“sentinel”) ligament of the external rectus muscle)
Rice. 2.1.13. The ratio of the fascial sheaths and fatty tissue to the muscular infundibulum (according to Parks, 1975): 1 - inferior oblique muscle; 2 - intermuscular septum; 3 - fatty tissue located outside the muscle funnel; 4 - inferior rectus muscle; 5 - external rectus muscle; 6 - Zinn ring; 7 - levator of the upper eyelid; 8- superior rectus 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 covering the bony walls of the orbit.
Periosteum (periorbita). The bones of the orbit, like all bones in the body, are covered by a layer of fibrous tissue called periosteum. It must 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 area of the superior and inferior orbital fissures, as well as at the optic canal, lacrimal gland and lacrimal crests. In other places it comes off easily. 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 optic opening, the periosteum gives off fibrous cords to the external muscles of the eye, as well as deep into the orbit, dividing the fatty tissue into lobules. It also envelops blood vessels and nerves.
In the optic canal, the periosteum unites with the endosteal layer of the dura mater.
The periosteum also covers the superior orbital fissure, with the exception of the passage of blood vessels and nerves.
In front, the periosteum covers the frontal, zygomatic and nasal bones. Through the inferior orbital fissure it spreads towards the pterygoid and palatine bones and the temporal fossa.
The periosteum also lines the lacrimal fossa, forming the so-called lacrimal fascia, which envelops the lacrimal sac. In this case, it spreads between the anterior and posterior lacrimal ridges.
The periosteum of the orbit is intensively supplied with blood vessels, which exclusively anastomose with each other, and is innervated by branches of the trigeminal nerve.
The periosteum, being a dense fibrous tissue, serves as a rather powerful obstacle to the spread of blood after injury, inflammatory process, tumors arising from paranasal sinuses nose However, it eventually collapses.
For Coffey's disease(infantile cortical hyperostosis) for an unknown reason, inflammation of the periosteum develops, leading to proptosis and increased intraorbital pressure to such an extent that glaucoma develops. Granular cell sarcoma also arises from the periosteum. The periosteum may be the only barrier between the contents of the orbit and the dermoid cyst, mucocele.
The potential space between the periorbita and the bones allows for fairly complete removal of orbital tissue for tumors. It is also necessary to point out that the periosteum must be preserved as much as possible when removing tumors, since it is an obstacle to its further spread.
Fascia. The organization of the fibrous tissue of the orbit has traditionally been discussed using anatomical terms. 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 methods of reconstructive anatomy (restoration of the volumetric arrangement of structures based on the analysis of serial sections), soft fabrics The orbits are currently considered as a complex biomechanical system that ensures 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 Tenon's capsule: The picture shows part of Tenon's capsule of the right orbit after removal of the eyeball (1 - conjunctiva; 2 - external rectus muscle; 3 - superior rectus muscle; 4 - optic nerve; 5 - superior oblique muscle; 6 - mouth of the meibomian glands; 7 - lacrimal punctum; 8 internal rectus muscle, 9 - lacrimal caruncle; 10 - Tenon's capsule; 11 - inferior oblique muscle; 12 - inferior rectus muscle)
is a connective tissue membrane that begins in the posterior part of the eye at the entrance of the optic nerve and moves anteriorly, enveloping the eyeball. Its anterior edge fuses with the conjunctiva of the eye in the corneoscleral region.
Although Tenon's capsule is tightly attached to the eye, it can still be separated from it at a certain distance. In this case, bridges of delicate fibrous tissue remain between the eyeball and the capsule. The resulting space is called potential Tenon space.
After enucleation of the eyeball, the implants are placed into the cavity of Tenon’s capsule or slightly back, within the muscular funnel.
Tenon's capsule is susceptible to various inflammatory processes. This occurs with orbital pseudotumors, 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 also facilitated by the presence of connective tissue elastic fibers.
Four muscles penetrate through Tenon's capsule (Fig. 2.3.14). This occurs approximately 10 mm from the limbus. When passing through Tenon's capsule, fibrous layers (intermuscular septa) depart into the muscle. The eyeball is covered with Tenon's capsule just behind the insertion of the rectus muscles. Thus, in front of the site of attachment of the muscles to the eyeball, three tissue layers are found: the most superficial - the conjunctiva, then Tenon's capsule and the most internal - the intramuscular septum (septa). It is important for the ophthalmologist to remember these formations, especially during muscle surgery. In cases of dissection of Tenon's capsule at a distance of more than 10 mm from the limbus, the fatty tissue of the orbit protrudes forward, leading to orbital prolapse.
Tenon's capsule forms a series of facial formations. In the horizontal plane, the capsule extends from the internal rectus muscle to the site 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 cords are removed, which happens when a levator resection is performed for ptosis, hypotropia (downward squint) may develop.
The fascial membranes of the external muscles of the eye are thin, especially in the posterior areas. Anteriorly they thicken significantly.
As stated above, fibrous cords extend from the external muscles of the eye towards the walls of the orbit. As they move away from the muscles, they are more and more clearly identified as anatomical formations. These fibrous cords are called suspensory ligaments. The most powerful ligaments are those that originate from the rectus muscles (internal and external) (Fig. 2.1.12, 2.1.15).
Rice. 2.1.15. Distribution of the fascial membranes of the right orbit (posterior view): 1 - top part fascia of the levator of the upper eyelid (central part of the superior transverse ligament); 2 - common part of the fascia of the levator of the upper eyelid and the superior rectus muscle; 3-medial ligament of the lacrimal gland; 4 superior transverse ligament (together with 1 and 2); 5 - intermuscular membranes; 6 - lacrimal gland; 7 - lower transverse ligament; 8 - posterior lacrimal ridge, 9 - medial capsular ligament (“sentinel” ligament); 10 - lateral tubercle of the orbit (Withnell ligament); 11-lateral capsular (“sentinel”) ligament; 12 - Tenon’s capsule (posterior); 13 - superior oblique muscle tendon and block
External suspensory ligament more powerful. It begins on the posterior surface of the lateral orbital eminence (Withnell's tubercle) and is directed towards the external fornix of the conjunctiva and the outer part of the orbital septum (Fig. 2.1.15).
Internal suspensory ligament a originates slightly behind the posterior lacrimal ridge and goes to the lateral part of the orbital septum, the lacrimal caruncle and the semilunar fold of the conjunctiva.
Upper transverse Withnell's ligament many authors consider it as the superior suspensory ligament.
Lockwood once described hammock-like structure, spreading under the eyeball from the inner wall of the orbit to the outer wall. It is formed by fusion of the fascia of the inferior rectus and inferior oblique muscles. This ligament can support the eye even after the maxilla and floor of the orbit are removed. It is more powerful in front of the inferior oblique muscle.
In the fascial membrane of all the external muscles of the eye one can find varying amounts smooth muscle fibers. Most of them are in the fascia of the superior and inferior rectus muscles.
The dense connective tissue surrounding the extrinsic muscles of the eye forms a funnel, the apex of which is located in the ring of zinn. The anterior border of the muscular funnel lies at a distance of 1 mm from the place of attachment of the external muscles of the eye to the sclera.
All strands of fibrous tissue of the orbit, including fibrous layers of adipose tissue lobules, belong to the fascicular system of the orbit. This dense connective tissue can be subject to pathological lesions such as nodular fasciitis, inflammatory pseudotumor.
More information about the fascial formations of the orbit can be found in the section on the description of the extrinsic muscles of the eye.
Fatty tissue of the orbit. All spaces of the orbit that do not contain the eyeball, fascia, nerves, vessels or glandular structures are filled with fatty tissue (Fig. 2.1.11). Fatty tissue acts as a shock absorber for the eyeball and other structures of the orbit.
In the anterior part of the orbit, the fatty tissue is dominated by fibrous connective tissue, while in the posterior parts there are fatty lobules.
The fatty tissue of the orbit is divided by a connective tissue septum into two parts - central and peripheral. Central part lies in the muscular funnel. In its anterior part, it is limited by the posterior surface of the eye, covered with Tenon's capsule. Peripheral part of the fatty tissue of the orbit is limited by the periosteum of the orbital walls and the orbital septum.
When the orbital septum is opened in the area of the upper eyelid, a preaponeurotic fat pad. Inside and below the block is the internal fat pad of the upper eyelid. It is lighter and denser. In the same area there is the subtrochlear nerve (n. intratrochlearis) and the terminal branch of the ophthalmic artery.
The main cellular component of fat lobules is lipocyte, the cytoplasm of which is made of neutral free and bound fats. Clusters of lipocytes are surrounded by connective tissue containing numerous blood vessels.
Despite the presence of a large amount of fatty tissue, tumors in the orbit, the source of which can be adipose tissue, are extremely rare (lipoma, liposarcoma). It is assumed that liposarcoma of the orbit generally develops not from lipocytes, but from ectomesenchymal 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, enhance the inflammatory process, causing a granulomatous reaction. This inflammatory process is completed by fibrosis of the affected and surrounding tissues. This condition is assessed as lipogranuloma. Trauma to the orbit, accompanied by necrosis of fatty tissue, can lead to the development of lipogranuloma.
Almost all pathological processes of a granulomatous nature (mycoses, Wegener's granulomatosis, etc.) involve adipose tissue.
Article from the book: .
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. This is important to take into account in clinical practice when probing wounds of the orbit and inserting a needle for injections. The orbit is limited by four walls: superior, inferior, medial and lateral, lined with periosteum, periorbita.
Top wall, paries superior, 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, 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 taken into account in clinical practice.
Medial wall, paries medialis, formed by the frontal process of the maxilla, 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 ethmoid 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 ocular part of the frontal bone. It separates the orbit from the temporal lobe.
In the orbit we observe a number of holes and slits through which it is combined with other formations of the skull: the optic nerve canal, canalis opticus, inferior orbital fissure, fissura orbitalis inferior, superior orbital fissure; fissura orbitalis superior, zygomatic-orbital foramen, foramen zygomaticoorbitale; nasolacrimal canal, canalis nasolacrimalis, anterior and posterior ethmoidal openings, foramen ethmoidalis anterior et posterior.
In the depths of the orbit, on the border between the upper and lateral walls, there is a comma-shaped fissure (superior orbital fissure, fissura orbitalis superior), formed by the body of the sphenoid bone, its greater and lesser wings. It connects the orbit to the cranial cavity (middle cranial fossa). All motor nerves of the eyeball pass through the superior orbital fissure: oculomotor, n. oculomotorus, blocky, n. trochlearis, abducens, n. abducens, and optic nerve, n. ophthalmicus, and the main venous collector of the orbit (superior orbital vein, v. ophthalmica superior). The concentration within the superior orbital fissure of a number of important formations explains in the clinic the emergence of a peculiar symptom complex, which, when this area is affected, is called superior orbital fissure syndrome.
At the border between the lateral and inferior walls of the orbit there is the inferior orbital fissure, fissura orbitalis inferior. It is limited by the lower edge of the greater wing of the sphenoid bone and the body of the upper jaw. In the anterior part, the fissure connects the orbit with the infratemporal, and in the posterior part, 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.
The anatomy of the orbit is a rather interesting section of the structure of the facial skull. Knowing how the orbit of the eye is formed gives us an understanding possible diseases and the consequences that may arise from its pathology.
Walls
The walls of the orbit form these paired depressions in the skull like pyramids with truncated apices. Without the eye, one can see how their wide base faces the front surface of the skull, and the narrower part is directed deep into its cavity.
With a normal build and eye size, the orbital cavity has the following metric indicators: depth up to five centimeters, entrance (in width and height) about four. This is enough for the walls of the orbit to contain the eyeball and its muscles, nerves, the ophthalmic artery and its branches, the fatty body, and the periorbita (thin periosteum of the orbit). At the entrance it is attached to the bone walls, but can easily peel off. During trauma or surgery, periorbital detachment forms a subperiosteal space in which blood and exudate can accumulate. This accumulation prevents the further spread of infection or neoplasms from the paranasal sinuses into the orbit.
The boundaries of the entrance are formed not only by bone walls, but by a thin layer of connective tissue, which is called the “orbital septum”. It is the anterior border and separator between the orbit itself and the eyelids.
In addition, the anterior orbital part is protected externally by the orbicularis oculi muscle, which runs along the upper and lower edges, forming a muscle ring. She closes her eyelids, closes her eyes and, under the influence of a reflex, is able to very quickly close her eyes from mechanical damage.
It should be understood that the structure of the eye socket is not uniform and is similar to a “puzzle” of bones of different thicknesses, since they belong to other different structures of the skull.
The roof or superior wall is the portion of the frontal bone and the lesser wing of the sphenoid.
The floor or lower wall is a combination of the body of the upper jaw and the palatine bone.
What is the lateral wall formed by? The zygomatic bone and the greater wing of the sphenoid.
Finally, the medial wall of the orbit is composed of the largest number of components:
- area of the frontal process of the maxilla;
- lacrimal and ethmoid bone;
- sphenoid bone.
Inflammation of the bones and periosteum of the orbits is called periostitis. Often its cause is an infection of the lacrimal sac, the skin of the eyelids and face, and teeth. The process may be purulent or without its formation. According to localization, periostitis can be anterior or posterior. The latter form is more difficult to detect and treat, and its consequences are more dangerous, since the optic nerve is compressed, leading to loss of vision, and pus may break through into the cranial cavity with the formation of fistulas.
Capsule
The walls of the orbit are lined with a special fibrous Tenon's membrane, which separates the eyeball with its structures and the orbital fatty body. The space between the sclera and this capsule allows the eye to rotate. Tenon's membrane has a developed ligamentous apparatus, whose fascia balances the movement of the eyeball. A person has for circular motion The eyes are set to a certain amplitude; when it is exceeded, a simultaneous displacement of the eye and Tenon’s capsule occurs.
Inflammation of this structure is called tenonitis, and it can be allergic or metastatic in nature. Purulent tenonitis, unlike diffuse inflammation of the orbit, does not lead to worsening general condition sick. But conjunctival chemosis is still present, eye movements are painful and limited.
The fibrous membrane is not airtight. Through it, muscles and nerves approach the eye. There are several ways in which they are brought into the orbital cavity.
"Moves"
As we have already found out, the orbit is formed bone structures. Special openings are provided to communicate the eye socket with the rest of the space. One has a round shape and a cross-section of about four millimeters. The location is almost in the center of the truncated apex of the trapezium, where the canal that contains the optic nerve and blood vessels begins.
Where the top and outer wall orbit, there is a slit-like opening called the superior large fissure. It carries the main ophthalmic nerves and veins - superior and inferior.
The palpebral fissure, called the inferior one, appears at the border of the inner and lower walls of the orbit and serves for conducting facial nerves and infraorbital. Also in this place, the blood supply to the orbit occurs from the connection of its vessels and blood plexuses from the pterygopalatine fossa.
The bottom is pierced by the infraorbital passage, which completes the groove of the same name. It opens onto the facial surface and serves as a conductor for the inferior orbital nerve and its vessels.
The medial region of the orbit is adjacent to the cavities of the nose and its ethmoidal labyrinth. These structures communicate through the anterior and posterior ethmoidal foramina, with their help nerves, arterial and venous vessels enter the internal space of the orbit. This connection makes it possible to develop a subperiosteal abscess of the walls of the orbits against the background of sinusitis or ethmoiditis. The outcome of the disease can be a breakthrough of pus, orbital phlegmon, purulent diseases of the brain, retrobulbar abscess and sepsis.
Characteristics of pathologies
Orbital diseases, like any other, can be congenital or acquired in origin. Thus, a violation of the structure of the bones that form the orbital cavity can occur as a result of craniofacial dysostosis (hereditary disorder of bone development) or due to the development of a neoplasm - a bone cyst or teratoma.
You can also group diseases of the orbit, starting from the cause, according to the etiological factor:
Inflammation may be acute or may progress to chronic form, which is typical for Wegener's granulomatosis, sarcoidosis, eosinophilic granuloma, amyloidosis.
1 – normal orbit, 2 – inflammation of soft tissues, 3 – inflammatory infiltrate, 4 – superiosteal abscess, 5 – phlegmon of the orbit, 6 – breakthrough of pus into the skull
Most often, doctors deal with phlegmon of the orbit (an accumulation of pus in its tissues). The cause of diffuse inflammation is most often staphylococci, streptococci, Haemophilus influenzae and Escherichia coli. They, as a rule, enter the orbit through the ethmoidal openings, connecting it with the paranasal sinuses, so eye complications often occur after sinusitis or sinusitis. The spread of inflammation is accompanied by high fever and headache in the eye area. Upon examination, you may notice protrusion of the eyes from the orbits with the impossibility of their reentry, the conjunctiva swells, and vision decreases. This complication requires immediate medical care. Subconjunctival injections of antibiotics are usually prescribed, and orbital drainage is performed if necessary. Complications of phlegmon can include vein thrombosis, blindness, and brain abscess.
Symptoms
Diseases that in one way or another relate to the orbit give certain symptoms, which are divided into basic and additional. They can be found in the table.
| What's happening | Cause | |
| Leading symptoms | ||
| Exophthalmos | Protrusion of the eyeball from the orbit | In the orbit, the volume of contents increases due to hemorrhage, foreign object, edema, tumor, inflammatory exudate, mucocele from the paranasal sinus, hemangioma |
| Enophthalmos | The eye fails, sinks | Atrophy of orbital filling, mainly due to nerve palsy or facial fracture |
| Horizontal offset | Swelling, trauma, special location of cyst or tumor | |
| Ophthalmoplegia | Reducing the volume of movement | Most pronounced on the side opposite to the displacement |
| Violation of reposition | Inability to move the eye inside the orbit | Normal displacement of 5 mm is not possible in the presence of tumor or edema |
| Additional | ||
| Pain | Occurs from irritation of nerve endings in a closed cavity | Inflammation, infection of bone, soft tissue and nerves |
| Expansion-narrowing of the palpebral fissure | Mechanical stretching or contraction of the eyelids | Accompanies exophthalmos and anophthalmos, respectively |
| Visible abnormality in the shape of an eyeball | Reason: prolonged compression | Neoplasm, cyst, edema |
| Changes in the fundus | Visible vascular pathologies | Congestion, hemorrhage |
| Orbital rim deformation | Retraction, swelling, redness | Spread of the inflammatory process to the orbital septum |
Diagnostics
In order to find out why the orbits hurt, today they use radiation examination. It is very informative, since the orbit and its contents vary greatly in density, which is clearly displayed during examination.
The most popular and available method- This is an x-ray, but computed tomography and magnetic resonance imaging are considered more informative. To get a complete picture of the integrity of the orbital walls and its contents, it is necessary to take not one, but a whole series of photographs in different projections. CT scan It also allows you to determine complications of injury in the form of retrobulbar or subperiosteal hematoma, hemorrhage into the intrathecal space of the optic nerve, inflammation of the fat body, cellulitis and orbital abscess.
MRI in cases of orbital examination is of auxiliary value, since the procedure is very lengthy and has a number of contraindications.
Treatment
Many inflammatory diseases of the orbits are amenable to drug treatment. However, there is a possibility that the therapy will not be successful, and to stop further infection or tumor process it is necessary to resort to removing the contents of the orbit. This surgical intervention is called exenteration. It is absolutely necessary when malignant tumor the orbit itself or the eyeball, the germination of metastases from the adnexal apparatus of the eye or sinuses. The operation can be performed with preservation of the eyelids or their complete excision. The periosteum of the orbit and its contents are completely removed, the optic nerve and supply vessels are intersected and cauterized with an electrocoagulator.
Modern techniques The operation still allows you to save the eyelids, and create conditions in the eye socket that allow you to wear a prosthesis and thus hide the resulting cosmetic defect.
I would like to remind you that it is easier to prevent a disease than to deal with its consequences, so if you experience discomfort in the eyes, headaches, or difficulty moving the eyeballs, be sure to consult a doctor for a thorough examination.