60. What anatomical formations pass through the superior orbital fissure?
All the oculomotor nerves (oculomotor, trochlear, abducent), 1 branch of the trigeminal nerve (ophthalmic nerve), superior ophthalmic vein pass through the superior orbital fissure.
61. List the main clinical signs of the syndrome of the superior orbital fissure.
When the bones of the orbit are affected, the so-called "syndrome of the superior orbital fissure". In this case, there will be symptoms of damage to the nerves and blood vessels passing through the upper orbital fissure (see above): 1. Complete paralysis of all muscles of the eyeball (complete ophthalmoplegia) 2. Lowering of the upper eyelid (ptosis) 3. Mydriasis - pupil dilation 4. Disorder sensitivity of the skin of the eyelids, conjunctiva and cornea (lesion of 1 pair of the trigeminal nerve) 5. Light exophthalmos (retrobulbar hematoma due to damage to the superior ophthalmic vein)
Section II. Refraction.
62. Indicate visual acuity if the subject sees line 10 of the Sivtsev table from a distance of 3.5 m.
In accordance with the Snellen formula, V = d / D. V - visual acuity d - distance from which the patient sees line 10 (3.5 m) D - distance from which the patient should see line 10 (5 m) Thus, V = 3.5 /5 = 0.7 Therefore, the visual acuity of the subject is 0.7
63. A 70-year-old patient has visual acuity of 1.0. Is it possible to judge the type of clinical refraction based on these data? If so, what kind of refraction are we talking about?
Yes, you can. If the patient's visual acuity is 1.0, then this means that his refraction is emmetropia or hyperopia (due to the strain of accommodation at a young age with hyperopia, visual acuity may be normal). However, in this case (a 70-year-old patient) the volume of accommodation is zero, hence the only possible option is emmetropia.
64. Does a 55-year-old person need glasses for near with hyperopia 2.5 d in both eyes? If yes, please write a prescription.
Yes, they are needed.
Rp.: Reading glasses.
Ou Sph + 5.0 diopters
65. Is surgical treatment of progressive myopia used? If yes, what is the operation?
Yes, it does. With progressive myopia, an operation is performed, aimed at strengthening the posterior segment of the eye. Strips of preserved autofascia or homosclera are passed along the posterior pole of the sclera and sutured 5-6 mm from the limbus. After engraftment of grafts, the sclera in the posterior pole thickens, which prevents its further stretching.
66. In the study of clinical refraction in the vertical meridian revealed hypermetropia 1.0 D, and in the horizontal - hypermegropia 2.5 D. Write a detailed diagnosis of this condition. H 1.0 D
Complex hyperopic astigmatism
H 2.5 D direct type (refraction in vertical
meridians are stronger).
67. What is the visual acuity of the patient if he distinguishes the details of the signs of the first row of the Sivtsev table from a distance of 1.5 m?
V=d/D=1.5/50= 0.03
68. Prescribe near glasses for a 70-year-old patient who has hypermetropia of 2.0 D in both eyes.
Rp.: Reading glasses.
Ou Sph + 5.0 diopters
69. O What factors determine the amount of accommodation?
The main factor determining the amount of accommodation is age patient. With age, physiological involutional processes occur in the lens, which are expressed in the compaction of its tissue, which leads to a gradual decrease in the volume of accommodation.
Increased myopia during the year by 1.0 diopters or more.
71. Define the concept of "astigmatism".
Astigmatism - a combination in one eye of different types of refraction or different degrees of one type of refraction.
72. If the subject has a visual acuity of 0.01, then from what maximum distance can he count the fingers of your hand?
V = d / D, therefore d = V x D V = 0.01 D \u003d 50 m (since the thickness of the fingers approximately corresponds to the thickness of the signs of the first line of the Sivtsev table) Thus, d \u003d V x D \u003d 0.01 x 50 m \u003d 0.5 m. The subject will be able to count the fingers from a distance of 50 cm.
73. Approximately how old is a patient who, having hypermetropia of 1.0 D, uses spherical glasses +2.0 D for near vision?
In this case, +1.0 D spherical glasses are required to correct hypermetropia. An additional +1.0 D is needed to correct presbyopia. Thus, the volume of accommodation in this patient is reduced by 1.0 D, which corresponds to an approximate age of 40 years.
74. Is there a connection between age and the position of the further point of clear vision?
No. The position of the further point of clear vision depends only on the type of clinical refraction.
75. Specify the type of the most acceptable correction of high degree anisometropia.
contact correction.
76. What can cause irregular astigmatism?
Irregular astigmatism is characterized by local changes in the refractive power on different segments of the same meridian. The causes of incorrect astigmatism are most often diseases of the cornea: injuries, scars, keratoconus, etc.
77. Does a 50-year-old patient need near glasses with myopia 2.0 D in both eyes? If yes, please write a prescription.
No, not needed. To correct myopia, glasses of -2.0 D will be required, and to correct presbyopia at this age, glasses of +2.0 D will be required. Therefore, glasses will not be needed.
78. List the indications for the appointment of bifocal glasses.
Myopia and hypermetropia of moderate and high degree in the elderly.
79. What drugs can impair near vision. Why?
The deterioration of near vision is associated with accommodation paralysis. Accommodation paralysis can be caused by atropine-like drugs (anticholinergics).
80. On the figure of the cross, give an example of mixed astigmatism.
With mixed astigmatism, there is myopia in one meridian, hypermetropia in the other:
M 1.0 D H2.0D
81. A spherical positive lens has a main focal length of 50 cm. What is its optical power?
D=1/F=1/ 0.5 = 2.0 D
82. Can a person at the age of 25 with hypermetropia of 2.5 D have visual acuity equal to 1? If yes, due to what factors?
Yes maybe. Due to the tension of accommodation (an increase in the curvature of the lens), with a slight degree of hypermetropia at a young age, the rays can be focused on the retina and distance vision does not suffer.
83. Would you write a prescription for near glasses for a 60-year-old patient who has 1.0D myopia in both eyes?
Rp.: Near glasses
Ou Sph+2.0 diopter
84. If it becomes necessary to correct anisometropia with spherical glasses, what is the main principle to be followed?
Basic principle: the difference in refractive power between spherical glasses on different eyes should not exceed 2.0 D.
85. What is the main difference between a spherical stack and a cylindrical one?
Spherical glass refracts light rays equally in all meridians (directions), while cylindrical glass refracts rays only in a plane perpendicular to the axis of the cylinder. In connection with this feature, cylindrical glasses are used in the correction of astigmatism.
86. What is the refractive power of the cornea?
87. Can a person aged 65 with hypermetropia of 2.5 D have visual acuity of 1? Why?
No, it cannot, since the volume of accommodation after 60 years is zero (that is, there is practically no accommodation). Therefore, the eye cannot, due to the increase in the curvature of the lens, focus the rays of light on the retina, and they are focused behind the retina (since the patient has hypermetropia).
88. A 72-year-old patient has myopia of 2.0 D in both eyes. The optical media are transparent, the fundus is normal. Write a prescription for glasses.
Rp.: Distance glasses Rp.: Near glasses
Ou Sph -2.0 D Ou Sph +1.0 D
Dp = 64 mm Dp = 62 mm
| " |
With a horizontal dimension of 40 mm, and vertical - 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) 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 runs along
Rice. 2.1.3. Bones that form the eye socket:
/ - orbital process of the zygomatic bone; 2 - cheekbone; 3 - fronto-sphenoid 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; // - block hole; 12 - ethmoid bone; 13 - nasal bone; 14 - frontal process of the upper jaw; 15 - lacrimal bone; 16 - upper jaw; 17 - infraorbital foramen; 18 - palatine bone; 19 - infraorbital sulcus; 20 - infraorbital fissure; 21 - zygomatic-facial opening; 22 - supraorbital fissure
suture lines. In this case, the fracture occurs both along the line of the zygomatic-maxillary suture in the downward direction or down-outward along the line of the zygomatic-frontal suture. The direction of the fracture depends on the site of application of the traumatic force.
The frontal bone forms the upper edge of the orbit (margo supraorbitalis), and its outer and inner parts are involved in the formation of the outer and inner edges of the orbit, respectively. In newborns, the upper edge is sharp. It remains sharp in women throughout life, and in men it rounds off with age. On the upper edge of the orbit from the medial side, the supraorbital notch is visible (incisura frontalis), containing the supraorbital nerve (n. supraorbitalis) and vessels. In front of the artery and nerve and slightly outward relative to the supraorbital notch is a small supraorbital foramen (foramen supraorbitalis), through which the eponymous artery penetrates into the frontal sinus and spongy part of the bone (arteria supraorbitalis).
Inner edge of the eye socket (margo medialis orbitae) in the anterior sections it is formed by the maxillary bone, which extends the process to the frontal bone.
The configuration of the inner edge of the orbit is complicated by the presence of lacrimal scallops in this area. For this reason, Whitnall proposes to consider the shape of the inner edge as a wavy spiral (Fig. 2.1.3).
Lower edge of the eye socket (margo inferior orbitae) formed by half maxillary and half zygomatic bones. The infraorbital nerve passes through the lower edge of the orbit from the inside (n. infraorbitalis) and the artery of the same name. They come to the surface of the skull through the infraorbital foramen. (foramen infraorbitalis), located several knut-ri and below the lower edge of the orbit.
2.1.3. Bones, walls and openings of the orbit
As indicated above, the orbit is formed by only seven bones that 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 behind and from the temporal fossa - in front. The orbit is located directly below the anterior cranial fossa and above the maxillary sinus.
Upper wall of the eye(Paries superior orbitae)(Fig. 2.1.4).
The upper wall of the orbit is adjacent to the frontal sinus and to the anterior cranial fossa. It is formed by the orbital part of the frontal bone, and behind - by the lesser wing of the sphenoid bone.
Bone formations of the orbit
Rice. 2.1.4. Upper wall of the eye (after Reeh et al., 1981):
/ - orbital wall of the frontal bone; 2 - fossa of the lacrimal gland; 3 - front lattice hole; 4 - a large wing of the sphenoid bone; 5 - upper orbital fissure; 6 - lateral orbital tubercle; 7 - block hole; 8 - posterior crest of the lacrimal bone; 9 - anterior crest of the lacrimal bone; 10 - sutura notra
Between these bones passes the sphenoid-frontal suture (sutura sphenofrontalis).
On the upper wall of the orbit, there are a large number of formations that play the role of "marks" used in 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 adipose tissue, mainly in the back (accessory fossa Roche Dovinyo (Roch on-Duvigneaud)). From below, the fossa is limited by the zygomatic-frontal suture (s. fronto-zygomatica).
The surface of the bone in the region of the lacrimal fossa is usually smooth, but roughness is sometimes determined at the site of attachment of the supporting ligament of the lacrimal gland.
In the anteromedial part, approximately 5 mm from the edge, the trochlear fossa and trochlear spine are located (fovea trochlearis and 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, the supraorbital nerve passes, which is a branch of the frontal branch of the trigeminal nerve.
At the top of the orbit, directly at the small wing of the sphenoid bone, there is an optic opening - the entrance to the optic canal (canalis opticus).
The upper wall of the orbit is thin and fragile. It thickens up to 3 mm in the place of formation of its small wing of the sphenoid bone (ala minor os sphenoidale).
The greatest thinning of the wall is observed in cases where the frontal sinus is exceptionally strongly 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 that a bone fracture occurs with the formation of sharp bone fragments during an injury. Through the upper wall, various pathological processes (inflammation, tumors) that develop in the frontal sinus spread into the orbit. It is necessary to pay attention to the fact that the upper wall is located on the border with the anterior cranial fossa. This circumstance is of great practical importance, since injuries to the upper wall of the orbit are often combined with brain damage.
The inner wall of the orbit(Paries me-dialis 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 (pro-cessus frontalis os zygomaticum), lacrimal braid
Rice. 2.1.5. The inner wall of the orbit (after Reeh et al., 1981):
1 - anterior lacrimal scallop and frontal process of the maxilla; 2 - lacrimal fossa; 3 - posterior lacrimal scallop; 4 - lamina papyracea ethmoid bone; 5 - front lattice hole; 6 -optic opening and canal, superior orbital fissure and spina recti lateralis; 7- lateral angular process of the frontal bone; 8 - inferoorbital margin with zygomatic-facial opening located on the right
Chapter 2
Tew and the lateral orbital surface of the sphenoid bone (fades orbitalis os sphe-noidalis), located most deeply. In the region of the seam between the ethmoid and frontal bones, anterior and posterior ethmoid openings are visible. (foramina ethmoidalia, anterius et pos-terius), through which the nerves and vessels of the same name pass (Fig. 2.1.5).
The lacrimal sulcus 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. The lacrimal groove, as it moves downward, passes into the lacrimal canal (sapa-lis nasolacrimalis).
The boundaries of the lacrimal fossa are delineated by two crests - the anterior and posterior lacrimal crests. (crista lacrimalis anterior et posterior). The anterior lacrimal crest continues down and gradually passes into the lower edge of the orbit.
The anterior lacrimal crest is easily palpable through the skin and is a marker during operations on the lacrimal sac.
As mentioned above, the main part of the inner wall of the orbit is represented by the ethmoid bone. Since it is the thinnest of all the bone formations of the orbit, it is through it that the inflammatory process most often spreads from the sinuses of the ethmoid bone to the tissues of the orbit. This can lead to the development of cellulitis, phlegmon of the orbit, thrombophlebitis of the veins of the orbit, toxic neuritis of the optic nerve, etc. Acutely developing ptosis often occurs in children. The inner wall is also the site of the spread of tumors from the sinus to the orbit and vice versa. Often it is destroyed during surgical interventions.
The inner wall is somewhat thicker only in the posterior sections, especially in the region of the body of the sphenoid bone, as well as in the region of the posterior lacrimal crest.
The ethmoid bone involved in the formation of the inner wall contains numerous air-containing bone formations, which can explain the rarer occurrence of fractures of the medial wall of the orbit than the thick bottom of the orbit.
It should also be mentioned that in the area of the lattice suture, abnormalities 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. The weakening of the inner wall also occurs with age. The reason for this is atrophy of the central parts of the bone plate.
In practical terms, especially when performing anesthesia, it is important to know the location of the anterior and posterior ethmoidal foramina through which the branches of the ophthalmic artery, as well as the branches of the nasociliary nerve, pass.
The anterior ethmoid openings open at the anterior end of the fronto-ethmoid suture, and the posterior ones near the posterior end of the same suture (Fig. 2.1.5). Thus, the front holes lie at a distance of 20 mm behind the anterior lacrimal crest, and the posterior ones at a distance of 35 mm.
In the depths of the orbit on the inner wall is the optic canal (canalis opticus), communicating the cavity of the orbit with the cavity of the skull.
The 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 on the temporal fossa (fossa temporalis), performed by the temporalis muscle (i.e. temporalis). It is delimited from the upper and lower walls by the orbital fissures. These borders extend anteriorly to the sphenofrontal (sutura sphenofrontalis) and zygomatic-maxillary (sutura zi-gomaticomaxilare) seams (Fig. 2.1.6).
The posterior section of the outer wall of the orbit forms only the orbital surface of the greater wing of the sphenoid bone, and the anterior section forms the orbital surface of the zygomatic bone. Between them is a wedge-zygomatic suture (sutura sphenozygomatica). The presence of this suture greatly simplifies the orbitotomy.
Rice. 2.1.6. The outer wall of the orbit (after Reeh et al., 1981):
1 - frontal bone; 2 - a large wing of the sphenoid bone; 3 - cheekbone; 4 - upper orbital fissure; 5 - spina recti lateralis; 6- infraorbital fissure; 7 - an opening through which a branch passes from the zygomatic-orbital nerve to the lacrimal gland; 8 - zygomatic-orbital foramen
Bone formations of the orbit
On the body of the sphenoid bone, at the junction of the wide and narrow parts of the upper orbital fissure, there is a small bony protrusion (thorn) (spina recti lateralis), from which the external rectus muscle originates.
The zygomatic-orbital foramen (/. zigomaticoorbital), through which the branch of the zygomatic nerve leaves the orbit (n. zigomatico-orbitalis), leading to the lacrimal nerve. The orbital eminence is also found in the same area. (eminentia orbitalis; orbital tubercle of Whitnell). Attached to it is the external ligament of the eyelid, the external "horn" of the levator, the ligament of Lockwood (lig. suspensorium), orbital septum (septum orbitale) and lacrimal fascia (/. lacrimalis).
The outer wall of the orbit is the place of the easiest access to the contents of the orbit during various surgical interventions. The spread of the pathological process to the orbit from this side is extremely rare and is associated, as a rule, with diseases of the zygomatic bone.
When performing an orbitotomy, the ophthalmosurgeon must know that the posterior edge of the incision is at a distance of 12-13 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. Such a neighborhood is important in practical terms, since in diseases of the maxillary sinus, the orbit is often affected 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 bottom of the orbit, the zygomatic bone (os zygomaticus) and orbital process of the palatine bone (processus orbitalis os zygomaticus)(Fig. 2.1.7). The palatine bone forms a small area at the back of the orbit.
The shape of the lower wall of the orbit resembles an equilateral triangle.
Between the lower edge of the orbital surface of the sphenoid bone (fades orbitalis os sphenoidalis) and the posterior edge of the orbital surface of the maxillary bone (fades orbitalis os maxilla) is the inferior orbital fissure (fissura orbitalis inferior). The line that can be drawn through the axis of the inferior orbital fissure forms the outer border of the inferior wall. The internal border can be determined along the course of the anterior and posterior ethmoid-maxillary sutures.
On the lateral edge of the lower surface of the maxillary bone, the infraorbital groove (groove) begins (sulcus infraorbitalis), which, as we move forward, turns into a channel (canalis infraorbitalis). They have
Rice. 2.1.7. Inferior wall of the orbit (after Reeh et al., 1981):
I- mandibular margin, maxillary part; 2 - infraorbital foramen; 3 - orbital plate of the upper jaw; 4 - inferoorbital groove; 5 - orbital surface of the large wing of the sphenoid bone; 6 - marginal process of the zygomatic bone; 7 - lacrimal fossa; 8 - infraorbital fissure; 9 - the place of the beginning of the lower oblique muscle
lies 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 a different density. It is denser near and somewhat outside the infraorbital nerve. Inside, the wall becomes noticeably thinner. It is in these places that post-traumatic fractures are localized. The lower wall is also the site of the spread of inflammatory and tumor processes.
visual channel(Canalis opticus)(Fig. 2.1.3, 2.1.5, 2.1.8).
Several inside the upper orbital fissure is the optic opening, which is the beginning of the visual canal. Separates the optic opening from the upper orbital fissure at the junction of the lower wall of the lesser wing of the sphenoid bone, the body of the sphenoid bone with its lesser wing.
The opening of the optic canal facing the orbit has dimensions of 6-6.5 mm in the vertical plane and 4.5-5 mm in 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. Deviation of this
Chapter 2
Rice. 2.1.8. Apex of the eye socket (after Zide and Jelks, 1985):
1 - infraorbital fissure; 2 - round hole 3 - upper orbital fissure; 4 - visual aperture and visual canal
axis from the sagittal plane, as well as down, relative to the horizontal plane, equals 38 °.
The optic nerve passes through the canal (p. opticus), ophthalmic artery (a. ophthalmica), immersed in the sheaths of the optic nerve, 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 one.
Already by the age of three, the visual canal reaches its usual 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 visual channel is observed with the development of various pathological processes. In young children, it is necessary to compare the diameter of the optic canal on both sides, since it has not yet reached the final dimensions. When detecting different diameters of the visual canals (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, gliomas of the optic nerve, aneurysms in the region of the sphenoid bone, 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 the expansion of the visual canal. These are benign arachnoid hyperplasia, fungal lesions (mycoses), granulomatous inflammatory reaction (syphilitic gumma, tuberculoma). Channel dilatation also occurs in sarcoidosis, neurofibroma, arachnoiditis, arachnoid cyst, and chronic hydrocephalus. .
The narrowing of the channel is possible with fibrous dysplasia or fibroma of the sphenoid bone.
Superior orbital fissure(Fissura orbitalis superior).
The shape and size of the supraorbital fissure differ significantly from individual to individual. It is located on the outer side of the visual opening at the top of the orbit and has the shape of a comma (Fig. 2.1.3, 2.1.6, 2.1.8, 2.1.9). It is limited by the small and large wings of the sphenoid bone. The upper part of the superior orbital fissure is narrower on the lateral side than on the medial side and from below. At the junction of these two parts is the spine of the rectus muscle (spina recti).
The oculomotor, trochlear nerves, the 1st 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 tendinus communis; Zinn ring) is located between the upper orbital fissure and the visual
Rice. 2.1.9. Location of structures in the region of the supraorbital fissure and zinn ring (according to Zide, Jelks, /985):
1 - external rectus muscle; 2 - superior and inferior branches of the oculomotor nerve; 3 - frontal nerve; 4 - lacrimal nerve; 5 - block nerve; 6 - upper rectus muscle; 7 - nasociliary nerve; 8 - levator of the upper eyelid; 9 - superior oblique muscle; 10 - abducens nerve; // - internal rectus muscle; 12 - inferior rectus muscle
Bone formations of the orbit
channel. The optic nerve, the ophthalmic artery, the upper and lower branches of the trigeminal nerve, the nasociliary nerve, the abducens nerve, and the sympathetic roots of the trigeminal ganglion enter the orbit through the Zinn ring and are thus located in the muscular funnel (Fig. 2.1.8, 2.1.9).
Immediately below the annulus in the supraorbital fissure passes the superior branch of the inferior ophthalmic vein (v. ophthalmica inferior). Outside the ring, on the lateral side of the upper orbital fissure, the trochlear nerve passes (n. trochlearis), superior ophthalmic vein (v. ophthalmica superior), as well as the lacrimal and frontal nerves (pp. lacrimalis et frontalis).
The expansion of the superior orbital fissure may indicate the development of various pathological processes, such as aneurysm, meningioma, chordoma, pituitary adenoma, benign and malignant tumors of the orbit.
Sometimes an inflammatory process of an unclear nature develops in the region of the upper orbital fissure (Talas-Hant syndrome, painful ophthalmoplegia). It is possible that inflammation spreads to the nerve trunks that go to the external muscles of the eye, which is the cause of the pain that occurs with this syndrome.
The inflammatory process in the region of the upper orbital fissure can lead to disruption of the venous drainage of the orbit. The consequence of this is swelling of the eyelids and eye sockets. Tuberculous encephalic periostitis has also been described, extending to structures located in the intraorbital fissure.
Inferior orbital fissure(Fissura orbitalis inferior)(Fig. 2.1.7-2.1.10).
The inferior orbital fissure is located in the posterior third of the orbit between the bottom and the outer wall. Outside, it is limited by a large wing of the sphenoid bone, and on the medial side by the palatine and maxillary bones.
The axis of the infraorbital fissure corresponds to the anterior projection of the visual opening and lies at a level corresponding to the lower edge of the orbit.
The infraorbital fissure extends forward more than the upper orbital fissure. It ends at a distance of 20 mm from the edge of the eye. It is this point that is the reference point for the posterior border during subperiosteal removal of the bone of the lower wall of the orbit.
Directly below the inferior orbital fissure and on the outer side of the orbit is the pterygopalatine fossa. (fossa pterygo-palatina), and in front - temporal fossa (fossa temporalis), performed by the temporalis 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.
Rice. 2.1.10. Temporal, infratemporal and pterygopalatine fossae:
/ - temporal fossa; 2 - pterygopalatine fossa; 3 - oval hole; 4 - pterygopalatine opening; 5 - infraorbital fissure; 6 - eye socket; 7 - cheekbone; 8 - alveolar process of the upper jaw
Behind the infraorbital fissure in the greater wing of the sphenoid bone is a round hole (foramen rotundum), connects the middle cranial fossa with the pterygopalatine fossa. Branches of the trigeminal nerve, in particular the maxillary nerve, penetrate into the orbit through this opening. (n. maxillaris). When leaving the hole, the maxillary nerve gives off a branch - the infraorbital nerve (n. infraorbi-talis), which, together with the infraorbital artery (a. infraorbitalis) enters the orbit through the infraorbital fissure. In the future, 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 go to the front 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 (lower ophthalmic) that drain blood from the orbit to the pterygoid plexus (plexus pterygoideus).
In the orbit, the zygomatic nerve divides into two branches - the zygomatic-facial (g. zigomaticofacialis) and zygomatic-temporal (n. zigomaticotemporalis). Subsequently, these branches penetrate into the canals of the same name in the zygomatic bone on the outer wall of the orbit and branch out in the skin of the zygomatic and temporal regions. From the zygomatic-temporal nerve towards the lacrimal gland, separate
Chapter 2. EYEBOCALL AND HAAS AUXILIARY APPARATUS
The nerve trunk, carrying secretory fibers, is lying.
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 sulcus, sulcus lacrimalis, continuing into the fossa of the lacrimal sac, fossa sacci lacrimalis. The latter passes downward into the nasolacrimal canal, canalis nasolacrimalis. There are two openings along the upper edge of the medial wall of the orbit: the anterior ethmoidal foramen, foramen ethmoidale anterius, at the anterior end of the frontoethmoid suture, and the posterior ethmoid foramen, foramen ethmoidale posterius, near the posterior end of the same suture. All 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 a thin periosteum.
The lateral wall of the orbit, paries lateralis orbitae, is formed in the posterior region by the orbital surface of the greater wing of the sphenoid bone, and in the anterior region by the orbital surface of the zygomatic bone. Between these bones passes the sphenoid-zygomatic suture, sutura sphenozygomatica. The upper and side 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 is formed by the small wings of the sphenoid bone. Between these two bones passes the wedge-frontal suture, sutura sphenofrontalis. At the root of each small wing is the 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 anteriorly and inside from the edge 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 large wing and the posterior edge of the orbital surface of the upper jaw is the lower orbital fissure, fissura orbitalis inferior, reaching the front end to the zygomatic bone. Through this gap, the cavity of the orbit communicates with the pterygopalatine and infratemporal fossae. On the lateral edge of the orbital surface of the upper jaw, the infraorbital sulcus, sulcus infraorbitalis, begins, 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 is the eye socket connected to?
The length of the anteroposterior axis (depth) of the G. in an adult varies from 4 to 5 cm, the width at the entrance to it 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 the most durable. The zygomatic, frontal, sphenoid, ethmoid bones, as well as the orbital surface of the body of the upper jaw take part in the formation of the walls (Fig.). The frontal sinus is laid in the upper wall of G.; the lower wall separates G. from the maxillary sinus. At the top of G. 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 an upper orbital fissure connecting the G.'s cavity with the cranial cavity; the ophthalmic, oculomotor, abducent, trochlear nerves and ophthalmic veins pass through it. On the border between the lateral and lower walls of the G. 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 G., there are anterior and posterior ethmoid openings through which nerves, arteries, and veins of the same name pass from the G. to the labyrinth of the ethmoid bone and the nasal cavity. In the thickness of the lower wall there is an infraorbital groove, passing anteriorly into the canal of the same name, opening on the front surface with a hole, in this canal passes the infraorbital nerve with the same artery and vein. In G. there are depressions - pits of the lacrimal gland and lacrimal sac; the latter passes into the bone nasolacrimal canal, which opens into the lower nasal passage. G.'s cavity contains the eyeball, fascia, muscles, blood vessels, nerves, lacrimal gland, and adipose tissue. The posterior part of the eyeball is surrounded by a vagina - Tenon's fascia, associated with the muscles, periosteum and bones of G. The muscular apparatus of G. consists of 6 muscles of the eyeball and the muscle that raises the upper eyelid. The blood supply of G. is carried out by the ophthalmic artery - a branch of the internal carotid artery. The outflow of blood occurs through the eye veins into the cavernous sinus. Sensitive innervation of G.'s tissues is carried out by the ophthalmic nerve - the 1st branch of the trigeminal nerve.
The orbit (orbita) is a paired bone cavity in the front of the skull, localized on the sides of the root of the nose. Three-dimensional reconstructions of the orbit are more like a pear than a four-sided pyramid traditionally mentioned in textbooks, which, moreover, loses one face in the region of the top of the orbit.
The axes of the orbital pyramids converge posteriorly and, accordingly, diverge anteriorly, while the medial walls of the orbit are located almost parallel to each other, and the lateral ones are at right angles to each other. If we take the optic nerves as reference points, then the angle of divergence of the visual axes normally does not exceed 45º, and the optic nerve and visual axis - 22.5º, which is clearly seen on axial computed tomograms.
The angle of divergence of the visual axes determines the distance between the orbits - the interorbital distance, which is understood as the distance between the anterior lacrimal crests. This is the most important element of facial harmony. Normal interorbital distance in adults varies from 18.5 mm to 30.7 mm, ideally being 25 mm. Both reduced (stenopia) and increased (euryopia) interorbital distance indicate the presence of a serious craniofacial pathology.
The length of the anterior-posterior axis ("depth") of the orbits in an adult is on average 45 mm. Therefore, all manipulations in the orbit (retrobulbar injections, subperiosteal separation of tissues, the size of implants introduced to replace bone defects) should be limited to 35 mm from the bony edge of the orbit, not reaching at least one centimeter to the optic canal (canalis opticus). It should be borne in mind that the depth of the orbit can vary within significant limits, the extreme variants of which are the "deep narrow" and "shallow wide" orbits.
The volume of the orbital cavity (cavitas orbitalis) is somewhat less than is commonly believed, and is 23-26 cm 3, of which only 6.5-7 cm 3 falls on the eyeball. In women, the orbital volume is 10% less than in men. Ethnicity has a great influence on the parameters of the orbit.
The edges of the entrance to the orbit
The edges (supraorbital - margo supraorbitalis, infraorbital - margo infraorbitalis, lateral - margo lateralis, medial - margo medialis) of the orbit make up the so-called "outer orbital frame", which plays an important role in ensuring the mechanical strength of the entire orbital complex and is part of a complex system of facial buttresses or "stiffening ribs" that dampen deformations of the facial skeleton during chewing, as well as with craniofacial injuries. In addition, the profile of the orbital margin plays an important role in shaping the contour of the upper and middle thirds of the face.
It should be noted that the edges of the orbit do not lie in the same plane: the lateral edge is displaced posteriorly compared to the medial one, and the lower one compared to the upper one, forming a spiral with right angles. This provides a wide field of view and gaze from below-outside, however, leaves the anterior half of the eyeball exposed to the impact of an injuring agent moving on the same side. The spiral of the entrance to the orbit is open in the region of the medial edge, where it forms the fossa of the lacrimal sac, fossa sacci lacrimalis.
The continuity of the supraorbital margin on the border between its middle and inner thirds is broken by the supraorbital notch (incisura supraorbitalis), through which the same artery, vein and nerve (a., v. et n. supraorbitalis) going from the orbit to the forehead and into the sinus are thrown. The shape of the cutout is very variable, its width is approximately 4.6 mm, and its height is 1.8 mm.
In 25% of cases (and in the female population - up to 40%), instead of a bone notch, there is a hole (foramen supraorbitale) or a small bone canal through which the indicated neurovascular bundle passes. The dimensions of the hole are usually smaller than the notches and are 3.0×0.6 mm.
- Infraorbital margin (margo infraorbitalis) , formed by the upper jaw and zygomatic bone, has less strength, therefore, with blunt trauma, the orbit undergoes transient wave-like deformation, which is transmitted to the lower wall and causes an isolated ("explosive") fracture with displacement of the lower muscle complex and fatty tissue into the maxillary sinus. In this case, the infraorbital margin most often remains intact.
- Medial edge of the orbit (margo medialis) in its upper part it is formed by the nasal part of the frontal bone (pars nasalis ossis frontalis). The lower part of the medial border consists of the posterior lacrimal crest of the lacrimal bone and the anterior lacrimal crest of the maxilla.
- The most durable are lateral and supraorbital margins (margo lateralis et supraorbitalis)
, formed by thickened edges of the zygomatic and frontal bones. As for the supraorbital margin, it is important
an additional factor in its mechanical strength is the well-developed frontal sinus, which dampens the impact on this area.
The walls of the orbit
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The walls of the orbit |
The structures that form them |
Bordering entities |
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Medial |
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Lateral |
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Top wall
Top wall the orbit is formed mainly by the frontal bone, in the thickness of which, as a rule, there is a sinus ( sinus frontalis), and partly (in the posterior section) for 1.5 cm - by the small wing of the sphenoid bone;
Similar to the lower and lateral walls, it has a triangular shape.
It borders on the anterior cranial fossa, and this circumstance determines the severity of possible complications in case of its damage. Between these two bones passes the wedge-frontal suture, sutura sphenofrontalis.
At the root of each small wing is the optic canal, canalis opticus, through which the optic nerve and ophthalmic artery pass.
On the side, at the base of the zygomatic process of the frontal bone, directly behind the supraorbital margin, there is a small depression - the fossa of the lacrimal gland (fossa glandulae lacrimalis), where the gland of the same name is located.
More medially, 4 mm from the supraorbital margin, there is a trochlear fossa (fossa trochlearis), next to which there is often a trochlear spine (spina trochlearis), which is a small bony protrusion near the transition of the upper wall to the medial. A tendinous (or cartilaginous) loop is attached to it, through which the tendon part of the upper oblique muscle of the eye, which sharply changes its direction here, passes.
Damage to the block during injuries or surgical interventions (in particular, during operations on the frontal sinus) entails the development of painful and persistent diplopia due to dysfunction of the superior oblique muscle.
Inner wall
The longest (45 mm) medial wall of the orbit (paries medialis) is formed (in the anterior-posterior direction) by the frontal process of the upper jaw, the lacrimal and ethmoid bones, as well as the small wing of the sphenoid bone. Its upper border is the frontal-ethmoid suture, the lower one is the ethmoid-maxillary suture. Unlike other walls, it has the shape of a rectangle.
The basis of the medial wall is the orbital (which stubbornly continues to be called "paper") plate of the ethmoid bone, 3.5-5.0 × 1.5-2.5 cm in size and only 0.25 mm thick. It is the largest and weakest component of the medial wall. The orbital plate of the ethmoid bone is slightly concave; therefore, the maximum width of the orbit is noted not in the plane of its entrance, but 1.5 cm deeper. As a result, percutaneous and transconjunctival approaches to the medial wall of the orbit with great difficulty provide an adequate view of its entire area.
The orbital plate consists of about 10 cells, separated by partitions (septa) into anterior and posterior parts. Large and numerous small partitions between the lattice cells (cellulae ethmoidales) strengthen the medial wall from the side of the nose, acting as buttresses. Therefore, the medial wall is stronger than the lower one, especially with a branched system of cribriform septa and a relatively small size of the orbital plate.
In 50% of the orbits, the ethmoid labyrinth reaches the posterior lacrimal crest, and in another 40% of cases, the frontal process of the maxilla. This anatomical variant is called "presentation of the ethmoid labyrinth".
At the level of the frontal-ethmoidal suture, 24 and 36 mm behind the anterior lacrimal crest, in the medial wall of the orbit there are anterior and posterior ethmoid openings (foramina ethmoidalia anterior et posterior), leading to the canals of the same name, which serve to pass from the orbit to the ethmoid cells and cavity nose of the same name branches of the ophthalmic artery and the nasociliary nerve. It should be emphasized that the posterior ethmoid foramen is located on the border of the upper and medial walls of the orbit in the thickness of the frontal bone, only 6 mm from the optic opening (mnemonic rule: 24-12-6, where 24 is the distance in mm from the anterior lacrimal crest to the anterior ethmoid foramen , 12 is the distance from the anterior ethmoid opening to the posterior one, and finally 6 is the distance from the posterior ethmoid opening to the optic canal). Exposure of the posterior ethmoid foramen during subperiosteal separation of the orbital tissues clearly indicates the need to stop further manipulations in this area in order to avoid injury to the optic nerve.
The most important formation of the medial wall of the orbit is the lacrimal sac fossa, located mostly in front of the tarsoorbital fascia, 13 × 7 mm in size, formed by the anterior lacrimal crest of the frontal process of the maxilla and the lacrimal bone with its posterior lacrimal crest.
The lower part of the fossa smoothly passes into the bone nasolacrimal canal (canalis nasolacrimalis), 10-12 mm long, passing through the thickness of the upper jaw and opening into the lower nasal passage 30-35 mm from the external opening of the nose.
The medial wall of the orbit separates the orbit from the nasal cavity, the ethmoid labyrinth, and the sphenoid sinus. This circumstance is of great clinical importance, since these cavities are often a source of acute or chronic inflammation that spreads per contuitatem to the soft tissues of the orbit. This is facilitated not only by the insignificant thickness of the medial wall, but also by the natural (anterior and posterior ethmoid) openings present in it. In addition, in the lacrimal bone and the orbital plate of the ethmoid bone, congenital dehiscences are often found, which are a variant of the norm, but serve as additional gates of infection.
Lateral wall
Lateral wall (paries lateralis) is the thickest and most durable, it is formed in its anterior half by the zygomatic bone, and in the posterior by the orbital surface of the large wing of the sphenoid bone. The length of the lateral wall from the edge of the orbit to the superior orbital fissure is 40 mm.
In front, the boundaries of the lateral wall are the fronto-zygomatic (sutura frontozygomatica) and zygomatic-maxillary (sutura zygomaticomaxillaris) sutures, behind - the upper and lower orbital fissures.
The central third - trigone (triangle or wedge-scaly seam, sutura sphenosquamosa) is highly durable. This triangle separates the orbit from the middle cranial fossa, thereby participating in the formation of both the lateral orbital wall and the base of the skull. This circumstance should be taken into account when performing external orbitotomy, bearing in mind that the distance from the lateral edge of the orbit to the middle cranial fossa is on average 31 mm.
The lateral wall of the orbit separates its contents from the temporal and pterygopalatine fossae, and in the region of the apex from the middle cranial fossa.
bottom wall
Inferior wall of the orbit
which is the "roof" of the maxillary sinus, is formed mainly by the orbital surface of the body of the upper jaw, in the anterior-outer section - by the zygomatic bone, in the posterior section - by a small orbital process of the perpendicular plate of the palatine bone. The area of the lower orbital wall is approximately 6 cm 2, its thickness does not exceed 0.5 mm, it is the only one in the formation of which the sphenoid bone does not take part.
The lower wall of the orbit has the form of an equilateral triangle. It is the shortest (about 20 mm) wall, not reaching the top of the orbit, but ending with the inferior orbital fissure and pterygopalatine fossa. The line passing through the inferior orbital fissure forms the outer border of the orbital floor. The internal border is defined as an anterior and posterior continuation of the ethmoid-maxillary suture.
The thinnest part of the bottom of the orbit is the infraorbital groove that crosses it approximately in half, passing anteriorly into the canal of the same name. Slightly stronger back of the inner half of the lower wall. The rest of its sections are very resistant to mechanical stress. The thickest point is the junction of the medial and inferior walls of the orbit, supported by the medial wall of the maxillary sinus.
The lower wall has a characteristic S-shaped profile, which must be taken into account when creating titanium implants to replace defects in the orbital floor. Giving the reconstructed wall a flat profile will lead to an increase in the orbital volume and the preservation of enophthalmos in the postoperative period.
The 15-degree elevation of the inferior orbital wall towards the apex of the orbit and its complex profile prevent the surgeon from inadvertently inserting the raspator into the deep regions of the orbit and make direct damage to the optic nerve during the reconstruction of the orbital floor unlikely.
With injuries, fractures of the lower wall are possible, which are sometimes accompanied by omission of the eyeball and limitation of its mobility upward and outward when the inferior oblique muscle is infringed.
Three of the four walls of the orbit (except the outer one) border on the paranasal sinuses. This neighborhood often serves as the initial cause of the development of certain pathological processes in it, often of an inflammatory nature. Germination of tumors emanating from the ethmoid, frontal and maxillary sinuses is also possible.
Seams of the orbit
The orbital surface of the greater wing of the sphenoid bone (facies orbitalis alae majoris ossis sphenoidalis) is not the same in thickness. The anterolateral third, which connects to the orbital surface of the zygomatic bone through the sphenozygomatic suture (sutura sphenozygomatica), and the posteromedial third, which forms the lower border of the superior orbital fissure, are relatively thin. Therefore, the zone of the wedge-zygomatic suture is convenient for external orbitotomy.
Near sphenoid-frontal seam (sutura sphenofrontalis) in the large wing of the sphenoid bone at the anterior edge of the superior orbital fissure there is a non-permanent hole of the same name containing a branch of the lacrimal artery - the recurrent meningeal artery (anastomosis between a. meningea media from the pool of the external carotid artery and the ophthalmic artery from the pool of the internal carotid artery).
sphenozygomatic the suture, due to its length and three-dimensional structure, plays an extremely important role in the process of repositioning the zygomatic bone in zygomatic-orbital fractures.
Fronto-zygomatic suture (sutura frontozygomatica) provides rigid fixation of the zygomatic bone to the frontal.
Fronto-ethmoid suture is considered an important identification point, marking the upper boundary of the lattice labyrinth. Accordingly, osteotomy above the fronto-ethmoid suture is fraught with damage to the dura mater (DTM) in the region of the frontal lobe.
zygomatic-facial (canalis zygomaticofacialis) and zygomaticotemporal (canalis zygomaticotemporalis) channels contain the same arteries and nerves that exit the cavity of the orbit through its lateral wall and terminate in the zygomatic and temporal regions. Here, they may turn out to be an "unexpected" finding for a surgeon cutting off the temporalis muscle during an external orbitotomy.
11 mm below the fronto-zygomatic suture and 4-5 mm behind the orbital margin is the orbital tubercle (tuberculum orbitale Whitnall) - a slight elevation of the orbital margin of the zygomatic bone, found in 95% of people. Attached to this important anatomical point are:
- fixing ligament of the lateral rectus muscle (tendon stretch, lacertus musculi recti lateralis, sentinel ligament in the terminology of V.V. Vit);
- suspensory ligament of the lower eyelid (lower transverse ligament of Lockwood, Lockwood);
- lateral ligament of eyelids;
- lateral horn of the aponeurosis of the muscle that lifts the upper eyelid;
- orbital septum (tarsoorbital fascia);
- fascia of the lacrimal gland.
Communication with the cavities of the skull
The outer, most durable and least vulnerable to diseases and injuries, the wall of the orbit is formed by the zygomatic, partly frontal bone and a large wing of the sphenoid bone. This wall separates the contents of the orbit from the temporal fossa.
The inferior orbital fissure is located between the lateral and inferior walls of the orbit and leads to the pterygopalatine and infratemporal fossae. Through it, one of the two branches of the inferior ophthalmic vein exits the orbit (the second flows into the superior ophthalmic vein), anastomosing with the pterygoid venous plexus, and the infraorbital nerve and artery, the zygomatic nerve and the ophthalmic branches of the pterygopalatine node also enter.
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 sulcus, sulcus lacrimalis, continuing into the fossa of the lacrimal sac, fossa sacci lacrimalis. The latter passes downward into the nasolacrimal canal, canalis nasolacrimalis.
There are two openings along the upper edge of the medial wall of the orbit: the anterior ethmoidal foramen, foramen ethmoidale anterius, at the anterior end of the frontoethmoid suture, and the posterior ethmoid foramen, foramen ethmoidale posterius, near the posterior end of the same suture. All 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 a thin periosteum.
Through the superior orbital fissure leading to the middle cranial fossa, the oculomotor ( n. oculomotorius), diverting ( n. abducens) and block-shaped ( n. trochlearis) nerves, as well as the first branch of the trigeminal nerve ( r. ophthalmicus n. trigemini). The superior ophthalmic vein also passes here, which is the main venous collector of the orbit.
The longitudinal axes of both eye sockets, drawn from the middle of their entrance to the middle of the optic canal, converge in the region of the Turkish saddle.
Holes and fissures of the eye socket:
- Bone canal optic nerve ( canalis opticus) 5-6 mm long. Begins in the eye socket with a round hole ( foramen optician) with a diameter of about 4 mm, connects its cavity with the middle cranial fossa. The optic nerve enters the orbit through this canal. n. opticus) and ophthalmic artery ( a. ophthalmica).
- Superior orbital fissure (fissura orbitalis superior). Formed by the body of the sphenoid bone and its wings, connects the orbit with the middle cranial fossa. It is covered with a connective tissue film through which the three main branches of the optic nerve pass into the orbit ( n. ophthalmicus) - lacrimal, nasociliary and frontal nerves ( nn. laerimalis, nasociliaris et frontalis), as well as the trunks of the trochlear, abducens and oculomotor nerves ( nn. trochlearis, abducens and oculomolorius). The superior ophthalmic vein leaves through the same gap ( n. ophthalmica superior). With damage to this area, a characteristic symptom complex develops - "syndrome of the superior orbital fissure", however, it may not be fully expressed when not all, but only individual nerve trunks passing through this fissure are damaged.
- Inferior orbital fissure (fissuga orbitalis inferior). Formed by the lower edge of the large wing of the sphenoid bone and the body of the upper jaw, it provides communication between the orbit and the pterygopalatine (in the posterior half) and temporal fossae. This gap is also closed by a connective tissue membrane, into which fibers of the orbital muscle are woven ( m. orbitalis) innervated by the sympathetic nerve. Through it, one of the two branches of the inferior ophthalmic vein leaves the orbit (the other flows into the superior ophthalmic vein), then anastomosing with the wing by a prominent venous plexus ( et plexus venosus pterygoideus), and includes the inferoorbital nerve and artery ( n. a. infraorbitalis), zygomatic nerve ( n.zygomaticus) and orbital branches of the pterygopalatine ganglion ( ganglion pterygopalatinum).
- round hole (foramen rotundum) is located in the greater wing of the sphenoid bone. It connects the middle cranial fossa with the pterygopalatine. Through this hole passes the second branch of the trigeminal nerve ( n. maxillaris), from which the infraorbital nerve departs in the pterygopalatine fossa ( n. infraorbitalis), and in the lower temporal - the zygomatic nerve ( n. zygomaticus). Both nerves then enter the orbital cavity (the first is subperiosteal) through the inferior orbital fissure.
- lattice holes on the medial wall of the orbit foramen ethmoidale anterius et posterius), through which the nerves of the same name (branches of the nasociliary nerve), arteries and veins pass.
- oval hole located in the greater wing of the sphenoid bone, connecting the middle cranial fossa with the infratemporal fossa. The third branch of the trigeminal nerve passes through it ( n. mandibularis), but it does not take part in the innervation of the organ of vision.
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Anatomical education |
Topographic and anatomical characteristics |
Content |
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Supraorbital notch (hole) |
Separates the medial and middle thirds of the supraorbital margin |
Supraorbital nerve (frontal nerve branch from ophthalmic nerve - V1) |
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Front lattice hole |
24 mm from the medial edge of the orbit at the level of the frontoethmoid suture |
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Rear lattice hole |
12 mm behind the anterior ethmoid opening, 6 mm from the optic opening |
Same name neurovascular bundle |
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Foramina of the zygomatic bone |
The zygomatic-facial and zygomatic-temporal neurovascular bundles |
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Nasolacrimal canal |
Begins in the fossa of the lacrimal sac and opens into the inferior nasal passage under the inferior nasal concha |
duct of the same name |
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infraorbital foramen |
Located 4-10 mm below the infraorbital margin |
Infraorbital neurovascular bundle (from V2) |
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visual channel |
Diameter 6.5 mm, length 10 mm |
Optic nerve, ophthalmic artery, sympathetic fibers |
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Superior orbital fissure |
Length 22 mm. Limited by the greater and lesser wing of the sphenoid bone. It is located below and lateral to the visual opening. Divided by the leg of the lateral rectus muscle into two parts: external and internal |
External: superior ophthalmic vein, lacrimal, frontal, trochlear nerves; Internal: superior and inferior branches of the oculomotor nerve, nasociliary nerve, abducens nerve; sympathetic and parasympathetic fibers |
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Inferior orbital fissure |
Formed by the sphenoid, zygomatic and palatine bones, the upper jaw |
Infraorbital and zygomatic nerves (V2), inferior ophthalmic vein |
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Sphenofrontal foramen (non-permanent) |
Wedge-frontal suture |
Recurrent meningeal artery anastomosing with the lacrimal artery |
Anatomical structures of the orbit
The eye socket is the bony receptacle for the eyeball. Through its cavity, the posterior (retrobulbar) section of which is filled with a fatty body ( corpus adiposum orbitae), pass the optic nerve, motor and sensory nerves, oculomotor muscles, the muscle that lifts the upper eyelid, fascial formations, blood vessels.
From the front (with closed eyelids), the orbit is limited by the tarsoorbital fascia, which is woven into the cartilage of the eyelids and fuses with the periosteum along the edge of the orbit.
The lacrimal sac is located anterior to the tarsoorbital fascia and is outside the orbital cavity.
Behind the eyeball at a distance of 18-20 mm from its posterior pole is the ciliary node ( ganglion ciliare) with a size of 2 x 1 mm. It is located under the external rectus muscle, adjacent in this area to the surface of the optic nerve. The ciliary ganglion is a peripheral nerve ganglion, the cells of which, through three roots ( radix nasociliaris, oculomotoria and sympathicus) are associated with the fibers of the corresponding nerves.
The bony walls of the orbit are covered with a thin but strong periosteum ( periorbita), which is tightly fused with them in the area of the bone sutures and the visual canal. The opening of the latter is surrounded by a tendon ring ( annulus tendineus communis Zinni), from which all the oculomotor muscles begin, with the exception of the inferior oblique. It originates from the lower bone wall of the orbit, near the inlet of the nasolacrimal canal.
In addition to the periosteum, the orbital fascia, according to the International Anatomical Nomenclature, includes the eyeball sheath, muscular fascia, orbital septum, and orbital fat body ( corpus adiposum orbitae).
Vagina of the eyeball ( vagina bulbi, former name fascia bulbi s. Tenoni) covers almost the entire eyeball, with the exception of the cornea and the exit point of the optic nerve. The greatest density and thickness of this fascia are noted in the region of the equator of the eye, where the tendons of the oculomotor muscles pass through it on the way to the places of attachment to the surface of the sclera. As it approaches the limbus, the vaginal tissue becomes thinner and eventually is gradually lost in the subconjunctival tissue. In places of suppression by extraocular muscles, it gives them a fairly dense connective tissue coating. Dense strands depart from the same zone ( fasciae musculares), connecting the vagina of the eye with the periosteum of the walls and edges of the orbit. In general, these strands form an annular membrane that is parallel to the equator of the eye and holds it in the orbit in a stable position.
Subvaginal space of the eye (former name - Spatium Tenoni) is a system of slits in loose episcleral tissue. It provides free movement of the eyeball in a certain volume. This space is often used for surgical and therapeutic purposes (performing implant-type sclero-strengthening operations, administering drugs by injection).
Orbital septum (septum orbitale) is a well-defined fascial-type structure located in the frontal plane. Connects the orbital edges of the cartilages of the eyelids with the bony edges of the orbit. Together they form, as it were, its fifth, mobile wall, which, with closed eyelids, completely isolates the cavity of the orbit. It is important to keep in mind that in the region of the medial wall of the orbit, this septum, which is also called the tarsoorbital fascia, is attached to the posterior lacrimal crest of the lacrimal bone, as a result of which the lacrimal sac, which lies closer to the surface, is partially located in the preseptal space, i.e., outside the cavity eye sockets.
The orbital cavity is filled with fat corpus adiposum orbitae), which is enclosed in a thin aponeurosis and permeated with connective tissue bridges that divide it into small segments. Due to its plasticity, adipose tissue does not interfere with the free movement of the oculomotor muscles passing through it (during their contraction) and the optic nerve (during movements of the eyeball). The fat body is separated from the periosteum by a slit-like space.
CT and MR Anatomy
The bony walls of the orbits are clearly visualized on CT scans, forming the shape of a truncated cone with its apex facing the base of the skull. It should be borne in mind that the computer integrated into the tomograph is not able to build an image of bone structures with a thickness of less than 0.1 mm.
Therefore, in some cases, the images of the medial, lower and upper walls of the orbit are intermittent, which can mislead the doctor. The small size of the bone "defect", the absence of angular displacements of the edges of the "fracture", the disappearance of the discontinuity of the contour on the following sections make it possible to distinguish such artifacts from a fracture.
Due to the low content of hydrogen protons, the bone walls of the orbits are characterized by a pronounced hypointense signal on T1- and T2-WI and are poorly distinguishable by MRI.
Fat body of the orbit it is clearly visualized both on CT (density 100 HU) and MRI, where it gives a hyperintense signal on T2 and low on T1-WI.
optic nerve at CT it has a density of 42–48 HU. On ultrasound, it is visualized as a hypoechoic strip. MRI allows you to trace the optic nerve all the way down to the chiasm. Especially effective for its visualization throughout are the axial and sagittal planes with fat suppression. The subarachnoid space surrounding the optic nerve is better visualized on T2WI with fat suppression in the frontal plane.
The thickness of the optic nerve on the axial section ranges from 4.2 ± 0.6 to 5.5 ± 0.8 mm, which is due to its S-shaped bend and apparent (!) thickening when entering the scanning plane and "thinning" when leaving her.
Shells of the eyeball with ultrasound and CT are visualized as a whole. The density is 50-60 HU. With MRI, they can be differentiated by the intensity of the MR signal. The sclera has a hypointense signal on T1- and T2-WI and looks like a clear dark strip; the choroid and retina are hyperintense on T1-WI and proton density-weighted tomograms.
Extraocular muscles on MR tomograms, the intensity of the signal differs significantly from the retrobulbar tissue, as a result of which they are clearly visualized throughout. At CT they have a density of 68-75 HU. The thickness of the superior rectus muscle is 3.8±0.7 mm, the superior oblique is 2.4±0.4 mm, the lateral rectus is 2.9±0.6 mm, the medial rectus is 4.1±0.5 mm, lower straight line - 4.9 ± 0.8 mm.
A number of pathological conditions are accompanied thickening of the eye muscles
- Causes of trauma include:
- contusion edema,
- intramuscular hematoma,
- orbital cellulitis, and
- carotid-cavernous and
- dural-cavernous fistula.
- To others -
- endocrine ophthalmopathy,
- pseudotumor of the orbit,
- lymphoma,
- amyloidosis,
- sarcoidosis,
- metastatic tumors, etc.
Superior ophthalmic vein on axial sections it has a diameter of 1.8 ± 0.5 mm, coronal - 2.7 ± 1 mm. The expansion of the superior ophthalmic vein detected on CT may indicate a number of pathological processes - difficult outflow from the orbit (carotid-cavernous or dural-cavernous fistula), increased inflow (arterio-venous malformations of the orbit, vascular or metastatic tumors), varicose expansion of the superior ophthalmic vein and, finally, endocrine ophthalmopathy.
The blood in the paranasal sinuses has a density of 35-80 HU, depending on the duration of the hemorrhage. Inflammatory processes often lead to a limited accumulation of fluid and look like parietal or polyp-like thickening of the mucous membrane with a density of 10-25 HU. Frequent radiological symptoms of a fracture of the orbital walls bordering the paranasal sinuses are emphysema of the orbit and paraorbital tissues, as well as pneumocephalus.
Syndrome of the superior orbital fissure is a pathology that is characterized by complete paralysis of the internal and external muscles of the eye and loss of sensitivity of the upper eyelid, cornea, and part of the forehead. Symptoms may be caused by damage to the cranial nerves. Painful conditions arise as complications of tumors, meningitis and arachnoiditis. The syndrome is typical for elderly and middle-aged people; in a child, such a pathology is diagnosed infrequently.
Anatomy of the apex of the orbit
The orbit, or eye socket, is a paired bony recess in the skull, which is filled with the eyeball and its appendages. Contains structures such as ligaments, blood vessels, muscles, nerves, lacrimal glands. The apex of the cavity is its deep zone, bounded by the sphenoid bone, which occupies about a fifth of the entire orbit. The boundaries of the deep orbit are delineated by the wing of the sphenoid bone, as well as by the orbital process of the palatine plate, the infraorbital nerve, and the inferior orbital fissure.
Orbit structure
The orbit is represented by three zones, each of which is limited by nearby structures.
- outdoor. It is formed by the zygomatic bone from below, the upper jaw (its frontal process), the frontal, lacrimal, nasal and ethmoid bones.
- Inner zone. It originates from the anterior end of the infraorbital fissure.
- Deep zone or apex of the orbit. It is limited to the so-called main bone.
Holes and slots
The apex of the orbit is associated with the following structures:
- wedge-frontal suture;
- external geniculate body;
- wedge-zygomatic suture;
- small and large wings of the main bone;
- wedge-shaped lattice seam;
- main bone;
- palatine bone;
- frontal process of the upper jaw.
The deep orbit has the following openings:
- visual aperture;
- lattice holes;
- round hole;
- infraorbital groove.
Deep orbit slots:
- lower orbital;
- superior orbital fissure.
Large nerves and blood vessels pass through the holes and through the cracks into the cavity of the orbit.
Causes of the syndrome
The syndrome of the upper orbital fissure can be caused by the following factors:
- Mechanical damage, eye injury.
- Tumors located in the brain.
- Inflammation of the arachnoid membrane of the brain.
- Meningitis.
- Entry into the eye area of a foreign body.
The occurrence of a symptom complex of the syndrome of the superior palpebral fissure is associated with damage to the nerves: oculomotor, abducent, block, ophthalmic.
Risk factors for the pathogenesis of the disease include living in environmentally polluted regions, eating foods containing carcinogens, and prolonged exposure to ultraviolet rays on the eyes.
Main features
The main manifestations and symptoms of pathology are:
- The drooping of the upper eyelid with the inability to lift it, resulting in a narrowing of the palpebral fissure of one eye. The cause of the anomaly is nerve damage.
- Paralysis of the internal and external eye muscles (ophthalmoplegia). The motor activity of the eyeball is lost.
- Loss of sensation in the skin of the eyelid.
- Inflammatory processes in the cornea.
- Pupil dilation.
- Anterior displacement of the eyeball (so-called bulging eyes).
- Retinal vein dilatation.
Some of the symptoms cause significant discomfort and are fixed by the patient, others are detected during examination by an ophthalmologist and further examination. The disease is characterized by a unilateral lesion with preservation of the functions of the second, healthy, eye.
The combination of several signs or some of them indicate a pathological syndrome, while the lower orbital fissure remains unchanged.
In the photo, patients show asymmetry of the eyes, ptosis of the affected organ.
Diagnostics
Diagnosis of the disease is complicated by the fact that other ophthalmic problems have similar symptoms. The syndrome manifests itself in the same way as the following conditions:
- myasthenic syndromes;
- aneurysm of the carotid artery;
- multiple sclerosis;
- periostitis;
- temporal arteritis;
- osteomyelitis;
- parasellar tumors;
- neoplasms in the pituitary gland;
- tumor formations in the orbit.
To differentiate the pathology from other diseases with similar manifestations, it is necessary to conduct diagnostic examinations in terms of ophthalmology and neurology:
- Collection of anamnesis with clarification of the nature of painful sensations and determination of the pathogenesis of the disease.
- Determination of visual fields and its acuity.
- Diaphanoscopy of the eye socket (illumination method).
- Ophthalmoscopy.
- Radioisotope scanning (to identify tumor formations).
- Ultrasound procedure.
- Biopsy (if a tumor is suspected).
- Computed tomography of the parts of the brain, disorders in which can provoke the symptom complex of the syndrome.
- Magnetic resonance imaging.
- Angiography (X-ray examination using a contrast agent).
After the discovery of the first manifestations of the syndrome, an urgent consultation of specialists is required: an ophthalmologist and a neurologist. Since the pathology is caused by damage to structures that are located near the orbital fissure, therapy involves acting on them in order to eliminate the root cause. Self-medication can lead to aggravation of the condition and the inability to provide effective medical care.
The fundamental method in the treatment of the syndrome is immunosuppressive therapy, which stops the protective response of the body in the case of an autoimmune nature of the disease. The low prevalence of pathology does not allow for large-scale studies, however, an analysis of the available data allows us to conclude that the use of corticosteroids is rational. The attending physician may appoint:
- "Prednisone"
- "Medrol",
- other analogues.
The drugs are administered intravenously or taken orally as tablets. The effect of such treatment appears already on the third or fourth day. If there is no improvement, there is a high probability that the disease was misdiagnosed.
Further monitoring of the patient's condition is important, since the steroids used also help to eliminate the symptoms of diseases and conditions such as carcinoma, lymphoma, aneurysm, chordoma, pachymeningitis.
In addition to immunosuppressive therapy, there is a treatment of the symptom complex, which is designed to alleviate the patient's condition. Analgesics are prescribed in the form of drops and tablets, anticonvulsants.
Vitamin complexes are shown as general strengthening agents. There is a reception of metabolic drugs for the regulation of metabolic processes in the affected structures of the eye.
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