Home Smell from the mouth Where is the human eye socket located? Bone formations of the orbit

Smell from the mouth

Where is the human eye socket located? Bone formations of the orbit

It is important to know the anatomy of the orbit and its dimensions in order to correctly perform an 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. Is in sphenoid bone, is the entrance to the third branch of the 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. She performs important function- drainage of 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 optic nerve.

Most common symptom diseases of the bone orbit of the skull - 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.

In case of inflammation, oncological diseases the orbit, its injury reduces visual acuity (up to 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 forward or backward deviation of the eye), 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

Anatomical features of the orbit, incl. age-related, largely determine and explain the clinical manifestations of its pathology.

Eyeballs located in two bony cavities of the skull, shaped like quadrangular pyramids. Their apex is directed posteriorly, towards the brain, and the anterior part, the base of the pyramid towards the face, constitutes the entrance to the orbit.
A child's eye socket is smaller than an adult's eye socket

Parameter Dimensions in mm
. in an adult in a newborn 10 years
Horizontal diameter 40 24 36
Vertical diameter 55 16.5 32
Depth 40-50 24 36
Angle between sagittal axes 45° 110°

In young children, the orbit is smaller and flatter than in adults.

The proximity of the orbit to other structures.

WITH cranial cavity the orbit is bordered by the posterior two-thirds of the upper wall formed by the frontal bone and the lesser wing of the sphenoid bone. In this part, the upper wall of the orbit is thin.
WITH frontal sinus the orbit borders in the anterior part of the upper wall. The frontal sinus in children is practically absent (remains rudimentary). By the age of 8 it is already formed. However, it reaches full development by the age of 25.
Ethmoid sinus borders on the inner wall of the orbit, formed by the maxillary, lacrimal, ethmoidal bones over a long distance, and the sphenoid bone. The ethmoid sinus is separated from the orbit by a thin bone plate as thin as a sheet of paper (Lamina Papyracla), which is also perforated with numerous openings for the passage of blood vessels and nerves.
Gaimorova ( maxillary sinus) . Its upper arch is formed by the lower wall of the orbit (zygomatic, maxillary and palatine bones). The upper wall of the maxillary sinus is relatively thin and is easily damaged by injury. The maxillary sinus in newborns looks like a small slit. Until the age of 7, she grows slowly. It reaches full development only by 15-20 years.
In early childhood, the lower wall of the orbit is located above two rows of primordia of milk and permanent teeth.
Main sinus. Does not directly border the orbit. However, it is located close to the frontal sinus and the ethmoidal labyrinth (posterior cells)
.

Contents of the eye socket

The orbital cavity contains:
1. eyeball;
2. fatty tissue;
3. muscles;
4. vessels;
5. nerves;
6. ligamentous apparatus.

The volume of the contents of the orbit is approximately 30 cubic meters. cm (for an adult), for a child - 20 cubic meters. cm.

1. Eyeball. Weight of the eyeball: in a newborn 2.3 g; in an adult - 7.5 g; the size of the anterior-posterior axis: 17-18 mm, in an adult - 22-24 mm.

2. Fat fiber. The eyeball in the orbit lies on a soft cushion of fatty tissue, which acts as a shock absorber for the eyeball and serves as protection for the vessels and nerves of the orbit. Fatty tissue consists of individual cells formed by a connective tissue membrane.

3. Muscles of the orbit. Each orbit contains 6 external muscles of the eyeball that ensure its movement.

The four rectus muscles begin at the apex of the orbit from the connecting ring surrounding the optic opening and are attached to the eyeball in its anterior section. This creates a muscular funnel in which the eyeball is located.

Two other muscles:
- the superior oblique muscle begins in the depth of the orbit;
- inferior oblique muscle - originates on the lower wall of the orbit.
Both eye muscles attach to the eyeball behind its equator.

4. Vessels of the orbital and eye system:
Arteries of the orbit They are distinguished by very thin walls, strongly convoluted and loosely connected with the fiber of the orbit.

Orbital artery - branch of the internal carotid artery- supplies blood to the organ of vision (with the exception of the eyelids, which are supplied with arterial blood through branches extending from the external carotid artery). The ophthalmic artery enters the orbit through the optic nerve canal and is located in the orbit in close proximity to the optic nerve. One of the branches of the ophthalmic artery is the central retinal artery. It penetrates through the dura mater into the body of the optic nerve and through it into the eyeball.

It should be emphasized:
- branches of the ophthalmic artery also supply the skin and muscles of the forehead, the lateral walls of the nose and anastomose with the branches of the external carotid artery;
- branches of the ophthalmic artery also supply blood to the paranasal sinuses.

Veins of the orbit
The outflow of blood from the eye occurs through the main trunk of the superior ophthalmic vein, its branches - the inferior ophthalmic vein, and their numerous branches that collect blood from the eyeball, external eye muscles, partially nasal sinuses, forehead and nose area, lacrimal gland and lacrimal sac, conjunctiva and sinuses of the dura mater.

The orbital veins do not have valves and the blood from them flows from the superior orbital vein into the cavernous sinus (mainly) and the facial vein.
In the genesis of pathology of the organ of vision, paranasal sinuses, and skull, the commonality of blood circulation and structure indications plays an important role.

5.Nerves of the orbit.
The orbit contains the ciliary ganglion and the optic nerve. motor nerves eye muscles, branches of the trigeminal nerve (sensory nerve) and branches of the sympathetic nerves - from the cervical plexus of the internal carotid artery and from the plexuses of the cavernous sinus.

Motor nerves of the orbit. These include the following cranial nerves: oculomotor nerve - III pair (n. osulomotoris), trochlear nerve - IV pair (n. trochlearis) and abducens nerve - VI pair (n. abducens).

Oculomotor nerve. Innervates:
- 3 rectus muscles of the eyeball - internal, superior, inferior;
- inferior oblique muscle;
- upper eyelid lifter;
- sphincter of the pupil;
- ciliary muscle.

The following important diagnostic fact should be emphasized: the oculomotor nerve, starting from the nuclei of the gray matter, passes along the base of the skull to the cavernous sinus, is located in the thickness of its outer wall and only then through the upper orbital fissure gets into the eye socket.

Trochlear nerve. Innervates the superior oblique muscle of the eyeball. Like the oculomotor nerve, it travels a long way along the base of the skull to the orbit. From its core, located next to the cores oculomotor nerve, passes to the cavernous sinus, is located in its outer wall, and then penetrates into the orbit through the superior orbital fissure.

Abducens nerve. Innervates the external eye muscle. At the base of the brain it penetrates into the cavernous sinus, where it is located next to the internal carotid artery.

Sensory nerves of the orbit. Sensitive innervation of the eye is carried out by the trigeminal nerve, its first branch (n. ophtalmicus), which departs from the Gasserian ganglion, penetrates the cavernous sinus, and then through the superior palpebral fissure into the orbital cavity. Its branches are the sensory nerves of the eyeball, eyelids, lacrimal sac, lacrimal gland, forehead skin and scalp to the parietal and temporal regions.

Ciliary (ciliary) node(ganglio ciliare). Connects the sensory and motor nerves of the orbit with the sympathetic nervous system. Its size is about 2 mm. Located posterior to the eyeball (approximately 10-18 mm from its posterior pole), near the optic opening. It is located under the external rectus muscle, adjacent to the superior outer part of the optic nerve.
The main number of sensory nerves of the eyeball is concentrated in the ciliary ganglion. The use of retrobulbar anesthesia in microsurgery is based on its blocking.

Knowledge of the appointments and topography of nerves by eye doctors - required condition in diagnosing visual, trophic and motor pathological changes organ of vision.

6. Physiological holes and crevices, as well as possible pathological holes in the bone walls of the orbit.

Numerous openings in the bony walls of the orbit for the nerves and vessels of the orbit, as well as openings that occur in cases of pathology (trauma, inflammatory processes, neoplasms), can contribute to the spread of the pathological process into the orbit from the border structures (brain, cavernous sinus, paranasal sinuses) , as well as into these structures from the orbit.
In the walls of the orbit there are also small openings for thin vessels and nerve branches connecting the orbital cavity with the paranasal sinuses.

With a horizontal dimension of 40 mm, and vertical - 32 mm(Fig. 2.1.3).

Most of the outer edge (margo lateralis) and the outer half of the bottom edge (margo infraorbitalis) The eye sockets are formed by the zygomatic bone. 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

Rice. 2.1.3. Bones that form the eye socket:

/ - orbital process of the zygomatic bone; 2 - cheekbone; 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 aperture; 10 - supraorbital notch; // - trochlear fossa; 12 - ethmoid bone; 13 - nasal bone; 14 - frontal process of the maxilla; 15 - lacrimal bone; 16 - upper jaw; 17 - infraorbital foramen; 18 - palatine bone; 19 - infraorbital groove; 20 - inferior orbital fissure; 21 -zygomaticofacial opening; 22 -superiorbital fissure

seam propagation lines. 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.

The frontal bone forms the superior edge of the orbit (margo supraorbitalis), 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. The supraorbital notch is visible on the upper edge of the orbit on the medial side. (incisura frontalis), containing the supraorbital nerve (n. supraorbitalis) and vessels. Anterior to the artery and nerve and slightly outward relative to the supraorbital notch is a small supraorbital foramen. (foramen supraorbitalis), through which the artery of the same name penetrates into the frontal sinus and the spongy part of the bone (arteria supraorbitalis).

Inner edge of the orbit (margo medialis orbitae) in the anterior sections it 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 of lacrimal ridges in this area. 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) formed half by the maxillary and half by the zygomatic bones. Through the lower edge of the orbit with inside pass through the infraorbital nerve (p. infraorbitalis) and the artery of the same name. They exit onto the surface of the skull through the infraorbital foramen (foramen infraorbitalis), located somewhat medially and below the lower edge of the orbit.

2.1.3. Bones, walls and openings of the orbit

As stated above, the orbit is formed by only seven bones, which are also involved in the formation of the facial skull.

The medial walls of the orbits are parallel. They are separated from each other by the sinuses of the ethmoid and sphenoid bones. The lateral walls separate the orbit 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).

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.

Bone formations of the orbit

Rice. 2.1.4. Superior wall of the orbit (after Reeh et al., 1981):

/ - orbital wall of the frontal bone; 2 - fossa of the lacrimal gland; 3 - anterior ethmoidal opening; 4 - greater 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 sphenoid-frontal suture runs between these bones (sutura sphenofrontalis).

On the upper wall of the orbit there are a large number of formations that play the role of “marks” used during surgical interventions. The fossa of the lacrimal gland is located in the anterolateral part of the frontal bone (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 Roch on-Duvigneaud). From below, the fossa is limited by the zygomaticofrontal suture (s. fronto-zigomatica).

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 at a distance of 5 mm from the edge, the trochlear fossa and trochlear spine are located (fovea trochlearis et spina trochlearis), on the tendon ring of which the superior oblique muscle is attached.

The supraorbital nerve, which is a branch of the frontal branch of the trigeminal nerve, passes through the supraorbital notch, located on the upper edge of the frontal bone.

At the apex of the orbit, directly at the lesser wing of the sphenoid bone, the optic foramen is located - the entrance to the optic canal (canalis opticus).

The upper wall of the orbit is thin and fragile. It thickens to 3 mm in the place 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 resorption occurs with age bone tissue top wall. 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 a bone fracture occurs during injury, 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 medialis orbitae)(Fig. 2.1.5).

The inner wall of the orbit is the thinnest (thickness 0.2-0.4 mm). It is formed by 4 bones: the orbital plate of the ethmoid bone (lamina orbitalis os ethmoi-dale), frontal process of the maxilla (processus frontalis os zigomaticum), tear braid

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 papyracea 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 - inferoorbital margin with zygomaticofacial foramen located on the right

Chapter 2. ORBITS AND AUXILIARY APPARATUS OF THE EYE

Tew and lateral orbital surface of the sphenoid bone (fades orbitalis os sphenoidalis), located most deeply. In the area of the suture between the ethmoid and frontal bones, the anterior and posterior ethmoidal foramina are visible (foramina ethmoidalia, anterius et pos-terius), through which the nerves and vessels of the same name pass (Fig. 2.1.5).

A tear trough is visible in the anterior part of the inner wall (sulcus lacrimalis), continuing into the fossa of the lacrimal sac (fossa sacci lacrimalis). It contains the lacrimal sac. As the tear trough moves downward, it becomes the nasolacrimal canal. (glander-lis nasolacrimalis).

The boundaries of the lacrimal fossa are outlined by two ridges - the 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. Acutely developing ptosis often occurs in children. 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.

The ethmoid bone, which participates in the formation of the internal wall, contains numerous air-containing bone formations, which may 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 ethmoidal suture, anomalies in the development of bone walls often occur, 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 front holes lie at a distance of 20 mm behind the anterior lacrimal ridge, and the posterior ones - at a distance of 35 mm.

The optic canal is located deep in the orbit on the inner wall. (canalis opticus), connecting the orbital cavity with the cranial cavity.

Outer wall of the orbit(Paries latera-lis orbitae)(Fig. 2.1.6).

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 with the temporal fossa (fossa temporalis), performed by the temporalis muscle (i.e. temporalis). It is delimited from the upper and lower walls by orbital fissures. These boundaries extend anteriorly to the sphenoid-frontal (sutura spheno-frontalis) and zygomaticomaxillary (sutura zi-gomaticomaxilare) seams (Fig. 2.1.6).

The posterior section of the outer wall of the orbit is formed only by the orbital surface of the greater wing of the sphenoid bone, and the anterior section is formed by the orbital surface of the zygomatic bone. Between them there is a sphenoid-zygomatic suture (sutura sphenozigomatica). The presence of this suture greatly simplifies orbitotomy.

Rice. 2.1.6. Outer wall of the orbit (after Reeh et al., 1981):

1 - frontal bone; 2 - greater wing of the sphenoid bone; 3 - cheekbone; 4 - superior orbital fissure; 5 - spina recti la-teralis; 6- inferior orbital fissure; 7 - the opening through which the branch passes from the zygomaticoorbital nerve to the lacrimal gland; 8 - zygomaticoorbital foramen

Bone formations of the orbit

On the body of the sphenoid bone at the junction of the broad and narrow parts There is a small bony protrusion (spike) located in the superior orbital fissure (spina recti lateralis), from which the external rectus muscle begins.

On the zygomatic bone, near the edge of the orbit, there is a zygomaticoorbital foramen (/. zigomaticoorbitale), through which the branch of the zygomatic nerve leaves the orbit (p. zigomatico-orbitalis), heading towards the lacrimal nerve. The orbital eminence is also found in this area (eminentia orbitalis; orbital tubercle of Withnell). The external ligament of the eyelid, the external “horn” of the levator, and Lockwood’s ligament are attached to it (lig. suspensorium), orbital septum (septum orbitale) and lacrimal fascia (/. lacrimalis).

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 should know that the posterior edge of the incision is at a distance of 12-13 from the middle cranial fossa mm in men and 7-8 mm among women .

Inferior wall of the orbit(Paries inferior orbitae)(Fig. 2.1.7).

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.

The lower wall of the orbit is formed by three bones: the orbital surface of the upper jaw (fades orbitalis os maxilla), occupying most of the floor of the orbit, the zygomatic bone (os zigomaticus) and the orbital process of the palatine bone (processus orbitalis os zigomaticus)(Fig. 2.1.7). The palatine bone forms a small area at the back of the eye socket.

The shape of the lower wall of the orbit resembles an equilateral triangle.

Between the inferior 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) the inferior orbital fissure is located (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.

The infraorbital groove (groove) begins on the lateral edge of the lower surface of the maxillary bone (sulcus infraorbitalis), which, as we move forward, turns into a channel (canalis infraorbitalis). They contain

Rice. 2.1.7. Inferior wall of the orbit (after Reeh et al., 1981):

I- 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

lies 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.

The lower 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.

Visual channel(Canalis opticus)(Fig. 2.1.3, 2.1.5, 2.1.8).

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 horizontal (Fig. 2.1.3, 2.1.5, 2.1.8).

The optic canal leads to the middle cranial fossa (fossa cranialis media). Its length is 8-10 mm. The axis of the optic canal is directed downward and outward. Rejection of this

Chapter 2. ORBITS AND AUXILIARY APPARATUS OF THE EYE

Rice. 2.1.8. Apex of the orbit (after Zide, Jelks, 1985):

1 - inferior orbital fissure; 2 - round hole; 3 - superior orbital fissure; 4 - optic foramen and optic canal

axis from the sagittal plane, as well as downwards, relative to the horizontal plane, is 38°.

The optic nerve passes through the canal (p. opticus), ophthalmic artery (a. ophthalmica), 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 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 section.

By the age of three, the visual canal reaches normal size. Its diameter is more than 7 mm it is already necessary to consider it a deviation from the norm and assume the presence of a pathological process. 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 dimensions. If different diameters of the visual canals are detected (at least 1 mm) one 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, optic nerve gliomas, aneurysms in the area of the sphenoid bone, and intraorbital spread of tumors of the optic chiasm are most often found. 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 lead to expansion of the visual canal. This is benign hyperplasia arachnoid, fungal infections (mycoses), granulomatous inflammatory reaction(syphilitic gumma, tuberculoma). Canal expansion also occurs in 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).

The shape and size of the superior orbital fissure varies 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). 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).

The oculomotor, trochlear nerves, the first branch of the trigeminal nerve, the abducens nerve, the superior orbital vein, the recurrent lacrimal artery, and the sympathetic root of the ciliary ganglion pass through the superior orbital fissure (Fig. 2.1.9).

Common tendon ring (anulus tendi-neus communis; ring of Zinn) is located between the superior orbital fissure and the optic

Rice. 2.1.9. Location of structures in the region of the superior orbital fissure and ring of Zinn (after Zide, Jelks, /985):

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; // - internal rectus muscle; 12 - inferior rectus muscle

Bone formations of the orbit

Channel. 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 upper branch inferior ophthalmic vein (v. ophthalmica inferior). Outside the ring, on the lateral side of the superior orbital fissure, the trochlear nerve passes (p. trochlearis), superior ophthalmic vein (v. ophthalmica superior), as well as the lacrimal and frontal nerves (paragraphs 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 disruption of the 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).

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 eye socket. 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 the pterygopalatine fossa (fossa pterygo-palatina), and in front - the temporal fossa (fossa temporalis), performed by the temporal muscle (Fig. 2.1.10).

Blunt trauma temporal muscle can lead to hemorrhage in the orbit as a result of destruction of the vessels of the pterygopalatine fossa.

Rice. 2.1.10. Temporal, infratemporal and pterygopalatine fossa:

/ - temporal fossa; 2 - pterygopalatine fossa; 3 - oval hole; 4 - pterygopalatine foramen; 5 - inferior orbital fissure; 6 - eye socket; 7 - cheekbone; 8 - alveolar process of the maxilla

Behind the lower orbital fissure in the large wing of the main bone there is a round hole (foramen rotundum), connecting the middle cranial fossa with the pterygopalatine fossa. Through this opening, branches of the trigeminal nerve, in particular the maxillary nerve, penetrate into the orbit (n. maxillaris). When leaving the foramen, the maxillary nerve gives off a branch - the infraorbital nerve (n. infraorbi-talis), 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 extend 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 zygomatic nerve also penetrates the orbit (p. zigo-maticus), minor branch of the pterygopalatine ganglion (g an g- sphenopalatina) and veins (inferior ophthalmic), draining blood from the orbit into the pterygoid plexus (plexus pterygoideus).

In the orbit, the zygomatic nerve divides into two branches - the zygomatic-facial (g. 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. From the zygomaticotemporal nerve towards the lacrimal gland, the

Chapter 2. ORBITS AND AUXILIARY APPARATUS OF HAAZ

The nerve trunk 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.

The medial wall of the orbit, paries medians orbitae, is formed (from front to back) by the lacrimal bone, the orbital plate of the ethmoid bone and the lateral surface of the body of the sphenoid bone. In the anterior part of the wall there is a lacrimal groove, sulcus lacrimalis, which continues into the fossa of the lacrimal sac, fossa sacci lacrimalis. The latter passes downwards into the nasolacrimal canal, canalis nasolacrimalis. There are two openings along the upper edge of the medial wall of the orbit: the anterior ethmoidal opening, foramen ethmoidale anterius, at the anterior end of the frontoethmoidal suture, and the posterior ethmoidal opening, foramen ethmoidale posterius, near the posterior end of the same suture. All the walls of the orbit converge at the optic canal, which connects the orbit to the cranial cavity. The walls of the orbit are covered with thin periosteum.

The lateral wall of the orbit, paries lateralis orbitae, is formed in the posterior part by the orbital surface of the greater wing of the sphenoid bone, in the anterior part - by the orbital surface of the zygomatic bone. Between these bones there passes the sphenoid-zygomatic suture, sutura sphenozygomatica. The upper and lateral walls are separated from each other by the superior orbital fissure, fissure orbitalis superior, which is located between the large and small wings of the sphenoid bone. On the orbital surface of the zygomatic bone there is a zygomatic orbital foramen, foramen zygomaticoorbitale.

76. What bones form the upper and lower walls of the orbit?

The upper wall, paries superior, is formed by the orbital part of the frontal bone, and its posterior section by the small wings of the sphenoid bone. Between these two bones there is a sphenoid-frontal suture, sutura sphenofrontalis. At the root of each lesser wing there is an optic canal, canalis opticus, through which the optic nerve and ophthalmic artery pass. At the anterior edge of the upper wall, closer to its lateral corner, there is a fossa of the lacrimal gland, fossa glandulae lacrimalis, and in front and inside of the edge there is a trochlear fossa, fovea trochlearis, and a trochlear spine, spina trochlearis.

The lower wall of the orbit, paries inferior orbitae, is formed mainly by the orbital surface of the upper jaw, as well as part of the orbital surface of the zygomatic bone and the orbital process of the palatine bone. Between the lower edge of the orbital surface of the greater wing and the posterior edge of the orbital surface of the upper jaw there is a lower orbital fissure, fissura orbitalis inferior, reaching the anterior end to the zygomatic bone. Through this gap the orbital cavity communicates with the pterygopalatine and infratemporal fossae. On the lateral edge of the orbital surface of the upper jaw, the infraorbital groove begins, sulcus infraorbitalis, which passes into the infraorbital canal, canalis infraorbitalis, which lies in the thickness of the anterior sections of the lower wall of the orbit.

77. What does the eye socket connect to?

The length of the anteroposterior axis (depth) of the orbit in an adult varies from 4 to 5 cm, the width at its entrance is about 4 cm, the height usually does not exceed 3.5-3.75 cm. The orbit has four walls, of which the lateral wall most durable. The zygomatic, frontal, sphenoid, ethmoid bones, as well as the orbital surface of the body of the upper jaw (Fig.) take part in the formation of the walls. The frontal sinus is located in the upper wall of the G.; the lower wall separates the G. from the maxillary sinus. At the apex of the eye there is an opening of the optic canal through which the optic nerve and ophthalmic artery pass. On the border between the upper and lateral walls there is the superior orbital fissure, which connects the G.’s cavity with the cranial cavity; the ophthalmic, oculomotor, abducens, trochlear nerves and ophthalmic veins pass through it. On the border between the lateral and lower walls of the orbital wall there is the lower orbital fissure, through which the infraorbital nerve passes along with the artery and vein of the same name, the zygomatic nerve, and venous anastomoses. On the medial wall of the gland there are anterior and posterior ethmoidal openings through which the nerves, arteries and veins of the same name pass from the gland into the labyrinth of the ethmoid bone and the nasal cavity. In the thickness of the lower wall there is an infraorbital groove, which passes anteriorly into the canal of the same name, which opens on the anterior surface with a hole; in this canal passes the infraorbital nerve with the artery and vein of the same name. In G. there are depressions - pits of the lacrimal gland and lacrimal sac; the latter passes into the bony nasolacrimal canal, which opens into the lower nasal meatus. G.'s cavity contains the eyeball, fascia, muscles, blood vessels, nerves, lacrimal gland, and fatty tissue. The posterior part of the eyeball is surrounded by a vagina - Tenon's fascia, associated with the muscles, periosteum and bones of the eyeball. The muscular apparatus of the eyeball consists of 6 muscles of the eyeball and the muscle that lifts the upper eyelid. The eyeball's blood supply is carried out by the ophthalmic artery, a branch of the internal carotid artery. The outflow of blood occurs through the ophthalmic veins into the cavernous sinus. Sensitive innervation of G. tissues is carried out optic nerve- 1st branch of the trigeminal nerve.

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

The eye socket usually does not have an exact geometric shape, but most often resembles a four-sided pyramid, with the base facing forward. The apex of the orbit faces the optic canal (Fig. 2.1.1-2.1.3).

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 opening; 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. Highest 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. The infraorbital nerve (n. infraorbitalis) and the artery of the same name pass through the lower edge of the orbit from the inside. 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

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 dura mater of the 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.

In the area of the suture between the ethmoid and frontal bones, the anterior and posterior ethmoidal openings (foramina ethmoidalia, anterius et posteriiis) are visible, through which the nerves and vessels of the same name pass (Fig. 2.1.5).

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.

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.

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

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 palatine bone forms a small area at the back of the eye socket.

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 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 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 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. These are 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.

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 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, in particular the maxillary nerve (n. maxillaris), penetrate into the orbit. 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 - inferior 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 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; 11 - fatty tissue; 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 happen during surgical intervention, 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 that 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 emanating from the paranasal sinuses. 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 starts 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 elastic fibers in the connective tissue surrounding Tenon’s capsule.

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 its 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 - upper part of the levator fascia of the upper eyelid ( central part 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 her 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.

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