What muscles are in the eyeball. oculomotor muscles

7-06-2012, 14:35

Description

The muscular apparatus of the eye is represented by 6 muscles: four straight lines - upper, lower, medial, lateral and two oblique - upper and lower. The place of origin of all the listed extraocular muscles, except for the inferior oblique, is the top of the orbit, where the muscles, merging, form a dense tendon ring located around the optic opening and the medial part of the superior orbital fissure. All rectus muscles in the form of flat wide ribbons are directed anteriorly, to the place of their attachment. Gradually diverging, all four rectus muscles of the eye form the so-called muscular funnel. The concept of muscle funnel plays important role in the topography of the orbit and in the differential diagnosis of pathological processes in the orbit, especially tumor, giving different symptoms and different forecast depending on the localization inside the funnel or outside it (Figure 2).

Figure 2.
The location of the external muscles of the eye in the orbit. Muscle funnel. The optic nerve passes between the diverging muscles along the axis of the muscle funnel. 1 - tendon ring of Zinn (annulus tendineus communis Zinnii); 2 - m. obliquus superior; 3 - the place of its passage through the block; 4 - m. rectus superior; 5 - m. obliquus inferior; 6 - m. rectus lateralis; 7 - m. rectus inferior; 8 - m. rectus medialis (no Beninghoff, 1957).

Perforating the Tenon's capsule at the level of the equator of the eye, the muscles are attached to the eyeball by wide tendons woven into the sclera.

Superior oblique muscle begins, like the rectus muscles of the eye, in the depths of the orbit, but outside the zinn ring, in the immediate vicinity of it, goes along the superomedial wall of the orbit, to the spina trochlearis. The muscle looks like a round cord. Passing through the block, it sharply narrows, upon exiting the block, it thickens again and turns posteriorly outward. Passing between the eyeball and the superior rectus muscle, it attaches behind the equator in the upper outer quadrant.

Inferior oblique muscle originates separately from all other muscles, from the inner bone wall of the orbit, goes downwards outward, encircling the eyeball between the lower wall of the orbit and the lower rectus muscle, rises upward and attaches to the sclera behind the equator in the same outer quadrant as the upper one.

According to their function, the muscles of the eyeball are divided into three pairs of antagonists, acting in exactly opposite directions:

- medial and lateral straight lines- turn the eye inward and outward;

- top and bottom straight- raise and lower the eyeball;

- oblique muscles- convey rotational movements to the eye.

However only the external and internal rectus muscles are pure antagonists, they rotate the eye in the horizontal plane, regardless of starting position eyeball. The remaining muscles act as pure antagonists only in the abduction position, when the axis of the orbit and the anatomical axis of the eye coincide. With the direct direction of gaze, when the anatomical axis of the orbit and the axis of the eye are at an angle of 25 - 27 degrees, the actions of the muscles are more complex:

- inferior rectus lowers the eyeball down, leads it, tilts its vertical meridian outward.

- superior rectus raises the eyeball up, leads it, tilts the vertical axis of the eye inwards.

- inferior oblique muscle raises the eye up, takes it away, tilts the vertical meridian outward.

- superior oblique muscle lowers the eyeball downwards, abducts it, tilts the vertical axis of the eye inwards.

In addition, the tone of the rectus muscles of the eye tends to pull the eyeball posteriorly, and the two oblique muscles anteriorly.

Thus, all muscular system eyes is in very fine balance.

Upper and lower eyelids protect the eyeball from the front and due to their blinking movements, which contribute to the uniform distribution of tears, they protect it from drying out.

The eyelids regulate the amount of light entering the eye.. Reflex closure of the eyelids occurs in response to mechanical, visual or
sound stimuli. The upward reflex movement of the eye (Bell's phenomenon) during closure of the eyelids protects the cornea from the ingress of foreign bodies and the drying of the cornea during sleep.

The edges of the eyelids form palpebral fissure(rima palpebrarum). (Figure 3).

Figure 3. Eyelid structure.
Sagittal section through both eyelids, conjunctival sac and anterior eyeball.
1 - supreorbital edge of the frontal bone; 2 - orbital fat; 3 - levator musculus palpebrae superior; bundles of its tendon fibers penetrate from the left through the circular muscle of the eyelids into the skin; 4 - tendon m. rectus superior. Eyeball: 5 - sclera; 6 - conjunctiva of the upper fornix - upper transitional fold; 7 - cornea; 8 - conjunctiva of the lower fornix; 9 - tendon m. rectus inferior; 10 - section of the inferior oblique muscle; 11 - lower orbital edge of the upper jawbone; 12 - orbital fat; 13 - tarsoorbital fascia - septum orbitale; 14 - cartilage of the lower eyelid; 15 - conjunctiva of the cartilage of the lower eyelid; 16 - cartilage conjunctiva upper eyelid; 17 - cartilage of the upper eyelid; 18 - m. orbicularis palpebrarum (according to M. L. Krasnov, 1952).

The border of the upper eyelid runs along the eyebrow, the lower eyelid along the lower edge of the orbit. Both eyelids are connected at the corners of the palpebral fissure by the internal and external ligaments (l.palpebrale mediale et laterale). The width and shape of the palpebral fissure varies normally: its horizontal length in an adult is 30 mm, its height varies from 10 to 14 mm, the edge of the lower eyelid does not reach the limbus 0.5-1 mm, the edge of the upper eyelid covers the limbus by 2 mm. The outer edge of the palpebral fissure is sharp, the inner edge is blunted in the form of a horseshoe-shaped bend. The latter limits the space called the lacrimal lake, in which the lacrimal caruncle (caruncula lacrimalis) is located - a small pink tubercle that has a skin structure with sebaceous and sweat glands, and a semilunar fold (plica semilunaris) of a thickened mucous membrane, which are vestiges of the third century. The free edges of the eyelids, about 2 mm thick, fit snugly against each other. They distinguish between anterior, posterior ribs and intermarginal space. On the front, more rounded rib, eyelashes grow (75-150 pieces), into the bulbs of which the excretory ducts of Zeiss's sebaceous glands open. Between the eyelashes are modified Moll's sweat glands. The excretory ducts of the meibomian glands open into the intermarginal space, the fatty secretion of which lubricates the edges of the eyelids, contributing to their sealing. At the inner corner of the eye, i.e. near the lacrimal lake, the intermarginal space narrows and passes into lacrimal papillae(papilli lacrimales). At the top of each of them is the lacrimal opening - an opening leading to the lacrimal canaliculus. The diameter of the lacrimal opening with open eyelids is 0.25 - 0.5 mm. The eyelids consist of 2 plates: the outer plate is formed by skin with muscles, the inner one is cartilage (tarsus) and the cartilage conjunctiva tightly fused with it.

Eyelid skin is very thin, tender, poor in fatty tissue, loosely connected to the underlying tissues. On the skin surface of the upper eyelid there is a deep orbito-palpebral upper, on the lower - orbito-palpebral lower folds. The first is located just below the upper orbital edge and is due to the tone of the anterior leg of the levator attached to the posterior surface of the skin. The thinness and slight displacement of the skin of the eyelids relative to the underlying tissues are good conditions for execution plastic surgery. But in this regard, the skin easily swells with local inflammation, venous congestion, a number of common diseases, hemorrhages and subcutaneous emphysema.

The mobility of the eyelids is provided by two groups of antagonist muscles: circular muscle th eyes and ve lifters to (m. levator palpebrae superior and m. tarsalis inferior).

Circular muscle of the eyelid- m. orbicularis oculi, s. palpebrarum, in which the palpebral, orbital and lacrimal parts are distinguished. The orbicular muscle is involved in lowering the upper eyelid and closing the palpebral fissure. The palpebral part is located within the eyelids themselves and does not go beyond their edges. Muscle fibers, both on the upper and lower eyelids, are woven into a dense medial ligament. Describing a semicircle along each eyelid, they are temporally attached to the outer commissure (lateral ligament) of the eyelids. Thus, they form two crescents in each eyelid. With the contraction of the palpebral part, blinking and slight closing of the eyelids occurs, as in a dream. The muscle fibers running along the edge of the eyelids between the roots of the eyelashes and the excretory ducts of the meibomian glands make up the ciliary muscle, or Riolan muscle (m.ciliaris Riolani), the contraction of which contributes to the secretion of the meibomian glands, as well as a tight fit of the edges of the eyelids to the eyeball. Orbital: fibers originate from the medial ligament and from the frontal segment of the maxilla and run along the periphery of the palpebral part of the orbicularis muscle. The muscle has view of a wide layer extending beyond the edges of the orbit and connects with the mimic muscles of the face. Having described a full circle, the muscle is attached near the place of its beginning. With the contraction of this muscle, together with the contraction of the palpebral part, tight closing of the eyelids is carried out.

Lacrimal part of the orbicular muscle of the eye(Horner's muscle) is represented by a deep portion of muscle fibers that begin somewhat posterior to the posterior crest of the lacrimal bone (crista lacrimalis posterior os lacrimale). Then they pass behind the lacrimal sac and are woven into the palpebral fibers of the orbicularis muscle, coming from the anterior lacrimal crest. As a result, the lacrimal sac is covered by a muscle loop, which, when contracting and relaxing during blinking movements, either expands or narrows the lumen of the lacrimal sac. Absorption and promotion of the lacrimal fluid along the lacrimal ducts is also facilitated by the contraction of those bundles of the lacrimal muscle that cover the lacrimal canaliculi.

In raising the upper eyelid and opening the palpebral fissure involved striated- m.levator palpebrae superior and smooth muscle- superior and inferior tarsal or Müllerian muscles. There is no muscle similar to the levator on the lower eyelid. The function of lifting the lower eyelid is weak pronounced muscle(m. tarsalis inferior) and the lower rectus muscle of the eye, which gives an additional tendon to the thickness of the lower eyelid.

M. levator palpebrae superior - starts in the depth of the orbit, where at the top it departs from the tendon ring (annulus tendineus communis) together with the rectus muscles of the eyeball, goes under the roof of the orbit anteriorly and at the level of the supraorbital edge passes into a wide tendon, which diverge fan-shaped and divide into three departments. The anterior part of the tendon in the form of thin bundles of fibers passes the tarsoorbital fascia and the orbicular muscle, diverges fan-shaped and merges with the subepithelial layer of the skin of the eyelids. back portion penetrates into the upper fornix of the conjunctiva and is attached here. Medium - the most powerful(Muller's muscle) is attached along the upper edge of the cartilage throughout its continuation. In its structure, the Müller muscle is reticulate, only part of its muscle bundles comes perpendicular to the edge of the cartilage, penetrating between the levator fibers and accompanying them in places to the upper edge of the cartilage. In this case, the levator tendon is stratified by smooth muscle fibers. The other part of the fibers approaches in an oblique direction. The third forms a well-defined transverse beam, weaving into the aponeurosis of the levator. Such contact with the levator aponeurosis provides not only elevation, but also prevents wrinkling of the eyelid. The lateral branches of the levator tendon fix it to the periorbit. Contraction of the muscle leads to pulling up simultaneously the skin, tarsal plate and conjunctival fornix. The main muscle is the muscle that lifts the upper eyelid, the auxiliary muscle of Müller lying under it, and when looking up, the frontal and superior rectus. The Muller muscle is innervated by the sympathetic nerve, and the remaining two portions are innervated by the III pair (oculomotor nerve).

With the contraction of the palpebral part of the circular muscle of the eye blinking and slight squeezing of the eyelids. It was established by electromyography that during voluntary blinking movements, the muscle, levator levator lid and orbicularis muscle act reciprocally: the activity of one is accompanied by the passivity of the other. If the upper eyelid slowly descends, then not only the activity of the muscle that lifts it decreases, but the antagonist (circular muscle) also remains passive. However, the general mechanism of closing the eyelids is more complicated due to the combined connection of the orbicular muscle with the mimic muscles on the one hand and the epidermis of the facial skin on the other. As a result of these connections, the eyelids, when closed, move not only up and down, but also in a horizontal direction - inwards, especially the lower one, which plays an important role in the advancement of the lacrimal fluid. When the eyelids close, the palpebral fissure shortens by 2 mm. In addition, the deep part of the palpebral portion of the circular muscle plays a leading role in the mechanism of lacrimal evacuation.

Ligaments of the eyelids

medial and lateral ligaments serve as the main apparatus that attaches various elements of the eyelid to the bone wall of the orbit: the edges of the eyelids themselves, the circular muscle of the eye, the edges of the cartilage and the tarsoorbital fascia. The medial ligament has two legs: front and back. The first in the form of a powerful collagen cord formed by the tendon of the orbicular muscle and merging with it by the collagen fibers of the medial sections of the cartilage and the orbicular fascia, runs in the horizontal direction in front of the lacrimal sac from the inner corner of the eyelids to the anterior lacrimal scallop (upper jaw). The cord is well palpable and becomes visible when the conjunctiva is pulled down, due to the tension of the internal ligament. Its back leg branches slightly away from the angle of the eyelids in the form of a tendon, bends around the lacrimal sac outside and behind and is attached to the posterior lacrimal crest of the lacrimal bone. Thus, the medial ligament covers the lacrimal sac both anteriorly and posteriorly. The lateral ligament of the eyelids, in comparison with the internal one, is poorly developed and is only a suture with a tendon bridge between the outer parts of the orbicular muscle of the upper and lower eyelids. The ligament is reinforced by the collagen fibers woven into it from the outer ends of the cartilage and the tarsoorbital fascia. It also runs horizontally from the outer corner of the eyelids to the bony tubercle of the zygomatic bone - tuberculum orbitae, where it is attached 2-3 mm away from the edge of the orbit.

Cartilage of the eyelid

It is a crescent-shaped plate with pointed edges (during incision in the intermarginal space, it easily splits into 2 plates). The collagen tissue that forms this plate with an admixture of elastic fibers is distinguished by a special cartilaginous density. Therefore, the name cartilage has taken root, although histologically, there are no elements of cartilage here. The pointed ends of the cartilages are firmly connected to each other by a binding of collagen fibers. Collagen fibers running from the edges of the cartilage to the medial and lateral ligaments of the eyelids fix the cartilage to the bony walls of the orbit. The density of cartilage determines its protective “skeletal” function. Cartilage repeats the convex shape of the eyeball. The length of the cartilage of the upper eyelid is 2 cm, the height is 1 cm, the thickness is 1 mm, the cartilage of the lower eyelid is smaller, its height is 5 mm. The anterior surface borders on loose connective tissue, the posterior one is closely connected with the conjunctiva.

In the thickness of the cartilage, modified sebaceous glands - meibomian(on the upper eyelid - 27-30, on the lower - about 20). They have an alveolar structure and secrete a fatty secret. Very short ducts of the alveoli flow into a long common excretory duct. The glands are parallel to each other and perpendicular to the free edge of the eyelids, occupying the entire height of the cartilage. The openings of the ducts open in front of the posterior rib of the eyelid in the form of pores. The secret of the meibomian glands serves as a fatty lubricant, protects the edges of the eyelids from maceration, prevents the transfusion of tears over the edge of the eyelids, contributing to its proper outflow.

Thus, the cartilage is like direct continuation of the tarsoorbital fascia, strongly associated with the orbital edge. This septum (septum orbitae) completely separates the contents of the orbit from the tissues of the eyelids, preventing the spread of pathological processes in depth. The back surface of the eyelids is covered with conjunctiva, which is tightly fused with cartilage, and outside it forms mobile vaults. Deep upper vault and shallower and easily accessible lower vault.

The conjunctiva is a thin, transparent mucous tissue, which in the form of a thin shell covers the entire rear surface eyelid (tunica conjunctiva palpebrarum), forms deep arches (fornix conjunctivae superior et inferior) and passes to the eyeball (tunica conjunctiva bulbi) ending at the limbus. In the conjunctiva of the eyelids, in turn, they distinguish the tarsal part - tightly fused with the underlying tissue, and the mobile - orbital, in the form of a fold transitional to the arches.

cartilage conjunctiva covered with a two-layer cylindrical epithelium and contains goblet cells at the edge of the eyelids, and the crypts of Henle at the distal end of the cartilage. Both those and others secrete mucin. Under the epithelium is the reticular tissue tightly soldered to the cartilage. At the free edge of the eyelids, the mucous membrane is smooth, but already 2-3 mm from it, roughness appears, due to the presence of papillae here.

Conjunctiva of transitional fold smooth and covered with 5-6 layer transitional epithelium also with big amount mucin-secreting goblet cells. Under the epithelium is loose connective tissue, consisting of elastic fibers and containing plasma cells and lymphocytes. The conjunctiva here is easily displaced and forms folds that facilitate the free movements of the eyeball.

On the border between the tarsal and orbital parts in the conjunctiva are additional lacrimal glands s, similar to the structure and function of the main lacrimal gland: Wolfring - 3 at the upper edge of the upper cartilage and one more below the lower cartilage, and in the area of ​​\u200b\u200bthe arches - Krause. The number of the latter reaches 6-8 on the lower eyelid and from 15 to 40 on the upper one. The blood circulation of the eyelids is carried out by two systems: the system of internal carotid artery(branches a.ophthalmica). a.supraorbitalis, a.lacrimalis and the system of the external carotid artery (anastomoses a.facialis and a.maxillaris, a.temporales superfacialis).

From the nasal side, they penetrate into the thickness of both eyelids from the depth of the orbit medial palpebral arteries of the eyelid- upper and lower (a. palpebralis mediales superiores et inferiores) - terminal branches of a. supraorbitalis. From the lateral side, a.palpebralis lateralis departs from a.lacrimalis. In the loose connective tissue layer between the musculocutaneous and tarsal-conjunctival plates of the eyelid, these medial and lateral branches of the palpebral arteries are directed towards each other, merge and form transversely located arterial arches: upper and lower - (arcus tarseus sup. et inf., or arr subtarsalis sup.et inf.). Both arterial arches run along the edges of the eyelid, the upper one is 1-2 mm from the edge of the eyelid, the lower one is 1-3 mm. At the level of the upper edge of the cartilage, a second peripheral arc or arcus tarseus sup is formed. On the lower eyelid, it is not always expressed. Between the peripheral and subtarsal arches there are vertical anastomoses with the arteries of the face. In the vascularization of the lower eyelid and the surrounding area are involved and branches of the infraorbital artery, departing from the maxillary artery (from the system of the external carotid artery). These arcs nourish all the tissues of the eyelids. The veins of the eyelid go according to the arteries, forming two networks: superficial and deep. There are much more anastomoses - with veins of the face and veins of the orbit. Because there are no valves in the veins, blood flows both into the venous network of the face and the orbit and through v.ophthalmica. superior, pouring blood into the cavernous sinus (therefore, there is a high probability of infection entering the cranial cavity). On their way to the orbit, the veins that drain blood from the eyelids also penetrate the orbital muscle. Its spasm in diseases of the eyeball (scrofula) can lead to swelling of the eyelids.

The most important anastomoses of the venous network of the eyelids- with the lacrimal vein (v.lacrimalis) and with the superficial temporal (v.temporalis superfacialis). Of particular importance are anastomoses with v.angularis, passing from the inner canthus and anastomosing with v.ophthalmica superior.

lymphatic system- a network of widely branched lymphatic vessels in both deep and subtarsal layers. Both networks anastomose widely with each other. The regional lymph node draining lymph from the upper eyelid is the anterior one, from the region of the lower eyelid it is the submandibular one.

Eyelid innervation

The III and VII pairs of cranial nerves take part in the motor innervation of the eyelids.

Circular muscle of the eye- a branch of the facial nerve (VII pair), its motor fibers provide closure of the eyelids. The facial nerve has a mixed composition: includes motor, sensory and secretory fibers that belong to the intermediate nerve, which is closely related to the facial nerve. The motor nucleus of the nerve is located in the lower part of the pons varolii at the bottom of the IV ventricle, bending around the nucleus of the abducens nerve localized from above, forms the knee (genu n. Facialis) and goes to the base of the brain in the cerebellopontine angle. Then, through the internal auditory opening, it enters the canalis facialis, in which it makes two turns with the formation of a knee and a knee node (geniculum et ganglium gen.). A large stony nerve (n. petrosus major) originates from the knee node, carrying secretory fibers to the lacrimal gland, extending from a special lacrimal nucleus, and the facial nerve itself exits the canal through the foramen stilomastoideum, giving off branches n at this level. auricularis posterior et r. digastricus. Then, with a single trunk, it pierces the parotid gland and divides into the upper and lower branch, which give off multiple branches, including to the circular muscle of the eye. The muscle that lifts the upper eyelid is innervated by the oculomotor nerve (III pair), only its middle part, i.e. Müller's muscle is a sympathetic nerve.

Nucleus of the oculomotor nerve located at the bottom of the sylvian aqueduct. The oculomotor nerve exits the skull through the superior orbital fissure, attaching sympathetic (from the plexus of the internal carotid artery) and sensory fibers (from n.ophthalmicus), passes through the cavernous sinus. In the orbit, within the muscular infundibulum, it divides into superior and inferior branches. The upper, thinner branch, passing between the upper rectus muscles and the muscle lifting the upper eyelid, innervates them.

Sensitive nerves to the upper eyelid and forehead skin come from the ophthalmic nerve (n.ophthalmicus) of the 1st branch of the trigeminal nerve, which exits through the superior orbital fissure and is divided into three main branches: n.lacrimalis, n.frontalis et n.nasociliaris. In the innervation of the skin of the eyelids, n.frontalis takes the main part., in the medial region of the upper eyelid, its branches n.supraorbitalis et n.supratrochlearis go under the skin. The ophthalmic nerve supplies sensitive innervation to the skin of the forehead, the anterior surface of the scalp, upper eyelid, inner corner of the eye, back of the nose, the eyeball itself, the mucous membranes of the upper part of the nasal cavity, the frontal and ethmoid sinuses, and the meninges. The lower eyelid receives sensitive innervation from n.infraorbitalis, extending from the 2nd branch of the trigeminal nerve (n.maxillaris). maxillary nerve exits the cranial cavity through a round hole and innervates the dura mater, skin, cartilage and conjunctiva of the lower eyelid (except for the innermost and outer corners of the palpebral fissure), the lower half of the lacrimal sac and the upper half of the nasolacrimal duct, the skin of the anterior part of the temporal region, the upper part of the cheek , wings of the nose, as well as the upper lip, upper jaw (and the teeth located on it), the mucous membranes of the back of the nasal cavity and the maxillary sinus.

Article from the book:

The muscles of the eye perform coordinated movements of the eyeballs, providing high-quality and volumetric vision.

There are only six oculomotor muscles in the eye, of which four are straight and two are oblique, which received this name because of the peculiarities of the muscle in the orbit and attachment to the eyeball. Muscle function is controlled by three cranial nerves: oculomotor, abducens, and trochlear. Each muscle fiber of this muscle group is richly supplied with nerve endings, which ensures special clarity and accuracy in movements.

Thanks to the oculomotor muscles, numerous options for the movement of the eyeballs are possible, both unidirectional: up, to the right, and so on; and multidirectional, for example, reducing the eyes when working at close range. The essence of such movements is that, due to the coordinated work of the muscles, the same image of objects falls on the same parts of the retina - the macular area, providing good vision and a sense of the depth of space.

Features of the structure of the muscles of the eye

There are 6 oculomotor muscles, of which 4 are straight, going in the forward direction: internal, external, upper and lower. The remaining 2 are called oblique, as they have an oblique direction of travel and attachment to the eyeball - the upper and lower oblique muscles.

All muscles, with the exception of the inferior oblique, start from a dense connective tissue ring surrounding the external opening of the optic canal. Anterior to its origin, 5 muscles form a muscular funnel, inside which the optic nerve, blood vessels, and nerves pass. Further, the superior oblique muscle gradually deviates upward and inwards, following to the so-called block. At this point, the muscle passes into the tendon, which is thrown over the loop of the block and changes its direction to oblique, attaching in the upper outer quadrant of the eyeball under the superior rectus muscle. The inferior oblique muscle originates at the lower inner edge of the orbit, runs outward and posteriorly under the inferior rectus muscle, and inserts in the inferior outer quadrant of the eyeball.

Approaching the eyeball, the muscles are surrounded by a dense capsule - Tenon's membrane and join the sclera at different distances from the limbus. Closest of all of the rectus muscles to the limbus, the internal is attached, and then the upper rectus, while the oblique muscles are attached to the eyeball slightly posterior to the equator, that is, the middle of the length of the eyeball.

The work of the muscles is regulated, for the most part, by the oculomotor nerve: the superior, internal, inferior rectus and inferior oblique muscles, with the exception of the external rectus, the work of which is provided by the abducens nerve and the superior oblique - the trochlear nerve. A feature of nervous regulation is that one branch of the motor nerve controls the work of a very small number of muscle fibers, due to which maximum accuracy is achieved when moving the eyes.

The movements of the eyeball depend on the features of muscle attachment. The places of attachment of the internal and external rectus muscles coincide with the horizontal plane of the eyeball, due to this, horizontal movements of the eye are possible: turning towards the nose during contraction of the internal rectus and towards the temple during contraction of the external rectus muscle.

The upper and lower rectus muscles mainly provide vertical eye movements, but since the line of attachment of the muscles is located somewhat obliquely with respect to the limbus line, simultaneously with the vertical movement, the eye also moves inwards.

The oblique muscles during contraction cause more complex actions, this is due to the peculiarities of the location of the muscles and their attachment to the sclera. The superior oblique muscle lowers the eye and turns outward, while the inferior oblique muscle raises it and also withdraws it outward.

In addition, the superior and inferior rectus muscles, as well as the oblique muscles, provide small turns of the eyeball clockwise and counterclockwise. Due to good nervous regulation and well-coordinated work of the muscles of the eyeball, complex movements are possible, both unilateral and directed to different sides, due to which there is a three-dimensionality of vision, or binocularity, and, in addition, the quality of vision increases.

Diagnostic methods

• Determination of eye mobility - the completeness of eye movements is assessed when tracking a moving object.
• Strabometry - assessment of the angle or degree of deviation of the eyeball from the midline in strabismus.
• Cover test - alternately cover one and the second eye to determine latent strabismus - heterophoria, and in case of obvious strabismus, its appearance is determined.
• Ultrasound diagnostics - determination of changes in the oculomotor muscles in close proximity to the eyeball.
• Computed tomography, magnetic resonance imaging - detection of changes in the oculomotor muscles throughout their length.

Disease symptoms

• Double vision is possible with obvious strabismus and with pronounced latent strabismus.
• Nystagmus - occurs when the ability of the eyes to fix objects is impaired.

The eye is a very delicate instrument of vision, which consists of a huge number of elements - vessels, nerves and, of course, muscles. The eye muscles, if classified by type, are quite diverse, each of them is responsible for its own area, but at the same time they work in a complex manner.

Anatomy of the eye

The muscles of the eye are commonly referred to as oculomotor muscles. A person has a total of 6 of them: 4 straight and 2 oblique. They were given a similar name for a reason - everything directly depends on their course inside the eye socket. In addition, various features of how they are attached to are also taken into account.

Several cranial nerves are responsible for the work of the muscles of vision:

1. oculomotor;
2. diverting;
3. side.

All muscle fibers are literally filled with nerve endings, which allows you to make their movements and actions as coordinated and more accurate as possible. In essence, their work is the most diverse and numerous eye movements. These can be options to the right-left, up-down, to the side, to the corner, etc. As a result of such well-established work of the muscles of vision, the same images can fall on the same areas of the retina, which allows a person to see significantly better and gives a great sense of deeper space.

The structure of these muscles

The muscles of the eye have as their beginning a dense connecting ring - it surrounds the holelocated inside. The optic nerve, blood vessels and nerves pass through this opening. From how the eye moves, the muscles of the eye are quite capable of changing direction. The oculomotor muscles are superior, internal, inferior rectus and oblique. The movements of the eyeball are determined in large part by how the muscles of the eye are attached. The place where the outer and inner straight options are attached to the horizontal surface of the apple determines its more correct movement in the horizontal direction.

Eye movements in the vertical direction are provided by the lower and upper oculomotor muscles. But due to the fact that these are attached a little obliquely, not only up and down movement is ensured, but also inward movement.

The oblique muscles of the eye are responsible for more complex movements of the apple. Doctors attribute this to the peculiarities of their location. For example, the upper oblique is responsible for lowering the eye and turning it outward, etc.

Symptoms of violations

If the muscles of the eyes hurt, you must definitely look for the cause. Violations of eye activity turns into a rather serious problem.

Moreover, it is enough that only one muscle fails for a person to feel serious discomfort.

At the same time, if the muscles of the eye fail, in most cases it will be noticeable to the naked eye.

One of these symptoms can be strabismus. Also, when the oculomotor muscles “break”, a problem may develop with focusing two eyes at once on one or another one object.

If you have problems with your eyesight, you should immediately consult a doctor.

Indeed, with age, the muscles of the eye become less pliable, and it will become almost impossible to correct the situation. And as a result, seeing normally will become quite problematic, and by old age you can generally go blind.

How is the problem diagnosed?

Today, there are many options for diagnosing problems with the muscles of the eyes. The final diagnosis is made on the basis of a visual examination and a number of fairly simple tasks. An important point is to determine the level of deviation of the eyeball from a symmetrical position.

Often for diagnosis, methods such as ultrasound, computed tomography and magnetic resonance imaging are used. It is these options that allow you to accurately and clearly determine the nature of the existing damage and deviations.

How to train your eyes?

In order for the eyes to work normally, it is necessary to engage in their general strengthening and healing.

And to do this is not so difficult. General strengthening classes should become a daily habit. Then the eyes will be healthier.

At home, it is proposed to use a whole range of classes at once, incl. And breathing exercises. This will saturate the tissues with oxygen and significantly improve vision. The exercise must necessarily include exercises for training both the external and internal muscles of the eye. So, for example, you can use different rotations of the eyes in one direction or another. For training internal options, an excellent solution would be an exercise in focusing the eyes.

Article author: Pavel Nazarov

The human visual system is one of the most complex biological mechanisms in the world. Structurally, it is a set of elements of the most diverse structures of the body, which, while working simultaneously, implement the visual function.

An important role in the implementation of the latter is played by the oculomotor apparatus, represented by muscle fibers and controlling them. In today's material, we will talk in more detail about the muscles of the eye, having examined their anatomy and possible pathologies. Interesting? Then be sure to read the material below to the end.

The muscles of the eye have a complex structure

As noted above, the human visual system is a rather complex system.

Its components are no exception and are also extremely complex. Perhaps, the oculomotor apparatus of the eyes considered today is still relatively uncomplicated. But first things first.

Consideration of the anatomy of the muscles of the eye system should begin with the fact that they are combined into a complex sensorimotor mechanism. The latter, by its nature, immediately implements two most important visual functions:

• First, it ensures the movement of the eyeballs behind the object of gaze.
• Secondly, the resulting image for each eye is combined into a single image.

Such a functional purpose determines the main feature of the oculomotor apparatus, which is expressed in the close connection of muscles (motor components) and nerve fibers (sensory elements).

Working together, these nodes of the muscular mechanism allow a person to see stably and with high quality. Structurally, eye muscles can be of two types:

1. Direct, which move the eyeballs along a straight axis and are attached to them only on one side.
2. Oblique, moving them more flexibly and having a double mount with those.

That the first, that the second muscles of the oculomotor apparatus act under the control of nerves, the main of which are considered to be oculomotor, abducent and block.

All nerve endings are responsible for the implementation of specific tasks and functions, but invariably go to the cerebral cortex, from which they are controlled.

The eye muscles, due to their diversity, can jointly organize eye movements in synchronous and asynchronous versions. In any case, the muscles of the eyes are divided into main and auxiliary.

The main difference between fiber types is that the former organize the movement of the eyeballs along the main axes, while others complement the variability of their functions (for example, they are responsible for lacrimation).

Examination of the oculomotor apparatus

The anatomy of the muscles of the eyes is much more complicated than what was discussed above. In the first paragraph of today's article, our resource drew attention only to the basis of the summarized issue, since its in-depth study within the framework of the article material is almost impossible.

In any case, the marked information will be enough to understand the whole essence of the human oculomotor system, so let's proceed to the consideration of methods for examining it for pathologies.

First, one important aspect should be noted - many methods from the field of ophthalmology are used to diagnose the correct functioning of the oculomotor muscles. The main tests and instrumental measures are:

• Examination of the eyeball.
• Evaluation of the process of tracking the movement of an object with the eye, both jointly with two apples, and separately.
• (ultrasound).
• Computed tomography (CT).
• Magnetic resonance imaging (MRI).

To obtain the most accurate and high-quality information about the correct operation of the oculomotor mechanism, the above diagnostic procedures are carried out in a single complex.

Some of them (examination, testing for tracking) are necessary to obtain basic data on the state of the eye muscles and identify the first signs of their pathologies. In the presence of unfavorable suspicions, a more global examination is required, therefore, they resort to ultrasound, CT and MRI.

By the way, these diagnostic methods make it possible to identify the pathological condition of not only the muscle fibers themselves, but also the nerves that control them.

An examination of the oculomotor apparatus is carried out exclusively by a professional doctor, namely -.

For really high-quality, fast and effective diagnostics, it is desirable to be examined in specialized centers specializing in ophthalmology. Do not forget that only such medical institutions have the necessary equipment and specialists with the required qualifications.

Possible pathologies of the muscles of the organs of vision

Muscles of the eye: schematic

Probably, there is no need to talk about the importance of a completely healthy state of the muscular apparatus of the eyes.

Everyone understands that only with the correct operation of the oculomotor mechanism, the human visual system is able to realize its functions.

Any deviation in the work of muscle fibers or nerves is manifested in impaired vision and the development of relevant pathologies. Most often, the muscular apparatus of the eyes suffers from:

• Myasthenia gravis is a weakness of the muscle fibers that does not allow them to properly move the eyeballs.
• Muscle paralysis or paresis, expressed in a structural lesion of the musculoskeletal structure and the inability of muscle fibers to perform their functions.
• Muscle spasm, accompanied by excessive muscle tension in the eyes and associated problems (for example, inflammation).
• Congenital anomalies of the oculomotor apparatus (aplasia, hypoplasia, etc.) - pathologies that are expressed in violations of the muscles of the eyes or their nerves from the very birth of a person and are anatomical defects.

Symptoms of damage to the musculoskeletal structure of the human eye system have a typical formation with different lesions. As a rule, among the signs of pathology include:

1. Diplopia is a violation of binocular vision (doubling the image of the surrounding reality obtained through the eyes).
2. Nystagmus is an involuntary eye movement that naturally interferes with the ability to focus on a specific area.
3. Pain in the eye sockets or head, which is the result of constant muscle spasm or malfunction of their nerves.

In the presence of the noted symptoms, the patient is necessarily assigned the set of investigative measures described in the previous paragraph of the article. Based on the results of all types of diagnostics, treatment is organized, which can be both conservative and surgical.

Note that in the case of damage to the muscles of the eye apparatus, direct surgery is most often used, since other methods of therapy, as a rule, are not particularly effective or completely meaningless.

The severity of the disease and the methods of its therapy are determined exclusively by a professional ophthalmologist, which should not be forgotten.

The prognosis for the treatment of 2/3 pathologies of the muscular mechanism of the eyes is favorable. However, it is important to understand that even with such a prognosis, there are risks of returning vision incompletely. If we are talking about congenital anomalies of the apparatus, then the situation is even more complicated.

With these pathologies, nothing can be done at all. Unfortunately, ophthalmology has not yet fully explored all aspects of the treatment of eye diseases of this kind.

On this note, the story on the topic of today's article will be completed. We hope that the presented material was useful for you and gave answers to your questions. As you can see anatomical structure eye muscles and their pathologies are not so difficult to consider. Health to you!

Anatomy of the muscles of the eye - the topic of the video:

7-06-2012, 14:35

Description

The muscular apparatus of the eye is represented by 6 muscles: four straight lines - upper, lower, medial, lateral and two oblique - upper and lower. The place of origin of all the listed extraocular muscles, except for the inferior oblique, is the top of the orbit, where the muscles, merging, form a dense tendon ring located around the optic opening and the medial part of the superior orbital fissure. All rectus muscles in the form of flat wide ribbons are directed anteriorly, to the place of their attachment. Gradually diverging, all four rectus muscles of the eye form the so-called muscular funnel. The concept of the muscular funnel plays an important role in the topography of the orbit and in the differential diagnosis of pathological processes in the orbit, especially tumors, which give different symptoms and a different prognosis depending on the localization inside the funnel or outside it (Figure 2).

Figure 2.
The location of the external muscles of the eye in the orbit. Muscle funnel. The optic nerve passes between the diverging muscles along the axis of the muscle funnel. 1 - tendon ring of Zinn (annulus tendineus communis Zinnii); 2 - m. obliquus superior; 3 - the place of its passage through the block; 4 - m. rectus superior; 5 - m. obliquus inferior; 6 - m. rectus lateralis; 7 - m. rectus inferior; 8 - m. rectus medialis (no Beninghoff, 1957).

Perforating the Tenon's capsule at the level of the equator of the eye, the muscles are attached to the eyeball by wide tendons woven into the sclera.

Superior oblique muscle begins, like the rectus muscles of the eye, in the depths of the orbit, but outside the zinn ring, in the immediate vicinity of it, goes along the superomedial wall of the orbit, to the spina trochlearis. The muscle looks like a round cord. Passing through the block, it sharply narrows, upon exiting the block, it thickens again and turns posteriorly outward. Passing between the eyeball and the superior rectus muscle, it attaches behind the equator in the upper outer quadrant.

Inferior oblique muscle originates separately from all other muscles, from the inner bone wall of the orbit, goes downwards outward, encircling the eyeball between the lower wall of the orbit and the lower rectus muscle, rises upward and attaches to the sclera behind the equator in the same outer quadrant as the upper one.

According to their function, the muscles of the eyeball are divided into three pairs of antagonists, acting in exactly opposite directions:

- medial and lateral straight lines- turn the eye inward and outward;

- top and bottom straight- raise and lower the eyeball;

- oblique muscles- convey rotational movements to the eye.

However only the external and internal rectus muscles are pure antagonists, they rotate the eye in the horizontal plane, regardless of the initial position of the eyeball. The remaining muscles act as pure antagonists only in the abduction position, when the axis of the orbit and the anatomical axis of the eye coincide. With the direct direction of gaze, when the anatomical axis of the orbit and the axis of the eye are at an angle of 25 - 27 degrees, the actions of the muscles are more complex:

- inferior rectus lowers the eyeball down, leads it, tilts its vertical meridian outward.

- superior rectus raises the eyeball up, leads it, tilts the vertical axis of the eye inwards.

- inferior oblique muscle raises the eye up, takes it away, tilts the vertical meridian outward.

- superior oblique muscle lowers the eyeball downwards, abducts it, tilts the vertical axis of the eye inwards.

In addition, the tone of the rectus muscles of the eye tends to pull the eyeball posteriorly, and the two oblique muscles anteriorly.

Thus, the entire muscular system of the eye is in very fine balance.

Upper and lower eyelids protect the eyeball from the front and due to their blinking movements, which contribute to the uniform distribution of tears, they protect it from drying out.

The eyelids regulate the amount of light entering the eye.. Reflex closure of the eyelids occurs in response to mechanical, visual or
sound stimuli. The upward reflex movement of the eye (Bell's phenomenon) during closure of the eyelids protects the cornea from the ingress of foreign bodies and the drying of the cornea during sleep.

The edges of the eyelids form palpebral fissure(rima palpebrarum). (Figure 3).

Figure 3. Eyelid structure.
Sagittal section through both eyelids, conjunctival sac and anterior eyeball.
1 - supreorbital edge of the frontal bone; 2 - orbital fat; 3 - levator musculus palpebrae superior; bundles of its tendon fibers penetrate from the left through the circular muscle of the eyelids into the skin; 4 - tendon m. rectus superior. Eyeball: 5 - sclera; 6 - conjunctiva of the upper fornix - upper transitional fold; 7 - cornea; 8 - conjunctiva of the lower fornix; 9 - tendon m. rectus inferior; 10 - section of the inferior oblique muscle; 11 - lower orbital edge of the upper jawbone; 12 - orbital fat; 13 - tarsoorbital fascia - septum orbitale; 14 - cartilage of the lower eyelid; 15 - conjunctiva of the cartilage of the lower eyelid; 16 - conjunctiva of the cartilage of the upper eyelid; 17 - cartilage of the upper eyelid; 18 - m. orbicularis palpebrarum (according to M. L. Krasnov, 1952).

The border of the upper eyelid runs along the eyebrow, the lower eyelid along the lower edge of the orbit. Both eyelids are connected at the corners of the palpebral fissure by the internal and external ligaments (l.palpebrale mediale et laterale). The width and shape of the palpebral fissure varies normally: its horizontal length in an adult is 30 mm, its height varies from 10 to 14 mm, the edge of the lower eyelid does not reach the limbus 0.5-1 mm, the edge of the upper eyelid covers the limbus by 2 mm. The outer edge of the palpebral fissure is sharp, the inner edge is blunted in the form of a horseshoe-shaped bend. The latter limits the space called the lacrimal lake, in which the lacrimal caruncle (caruncula lacrimalis) is located - a small pink tubercle that has a skin structure with sebaceous and sweat glands, and a semilunar fold (plica semilunaris) of a thickened mucous membrane, which are vestiges of the third century. The free edges of the eyelids, about 2 mm thick, fit snugly against each other. They distinguish between anterior, posterior ribs and intermarginal space. On the front, more rounded rib, eyelashes grow (75-150 pieces), into the bulbs of which the excretory ducts of Zeiss's sebaceous glands open. Between the eyelashes are modified Moll's sweat glands. The excretory ducts of the meibomian glands open into the intermarginal space, the fatty secretion of which lubricates the edges of the eyelids, contributing to their sealing. At the inner corner of the eye, i.e. near the lacrimal lake, the intermarginal space narrows and passes into lacrimal papillae(papilli lacrimales). At the top of each of them is the lacrimal opening - an opening leading to the lacrimal canaliculus. The diameter of the lacrimal opening with open eyelids is 0.25 - 0.5 mm. The eyelids consist of 2 plates: the outer plate is formed by skin with muscles, the inner one is cartilage (tarsus) and the cartilage conjunctiva tightly fused with it.

Eyelid skin is very thin, tender, poor in fatty tissue, loosely connected to the underlying tissues. On the skin surface of the upper eyelid there is a deep orbito-palpebral upper, on the lower - orbito-palpebral lower folds. The first is located just below the upper orbital edge and is due to the tone of the anterior leg of the levator attached to the posterior surface of the skin. The thinness and easy displacement of the skin of the eyelids relative to the underlying tissues are good conditions for performing plastic surgery. But in this regard, the skin easily swells with local inflammation, venous congestion, a number of common diseases, hemorrhages and subcutaneous emphysema.

The mobility of the eyelids is provided by two groups of antagonist muscles: orbicularis oculi muscle and vein lifters to (m. levator palpebrae superior and m. tarsalis inferior).

Circular muscle of the eyelid- m. orbicularis oculi, s. palpebrarum, in which the palpebral, orbital and lacrimal parts are distinguished. The orbicular muscle is involved in lowering the upper eyelid and closing the palpebral fissure. The palpebral part is located within the eyelids themselves and does not go beyond their edges. Muscle fibers, both on the upper and lower eyelids, are woven into a dense medial ligament. Describing a semicircle along each eyelid, they are temporally attached to the outer commissure (lateral ligament) of the eyelids. Thus, they form two crescents in each eyelid. With the contraction of the palpebral part, blinking and slight closing of the eyelids occurs, as in a dream. The muscle fibers running along the edge of the eyelids between the roots of the eyelashes and the excretory ducts of the meibomian glands make up the ciliary muscle, or Riolan muscle (m.ciliaris Riolani), the contraction of which contributes to the secretion of the meibomian glands, as well as a tight fit of the edges of the eyelids to the eyeball. Orbital: fibers originate from the medial ligament and from the frontal segment of the maxilla and run along the periphery of the palpebral part of the orbicularis muscle. The muscle has view of a wide layer extending beyond the edges of the orbit and connects with the mimic muscles of the face. Having described a full circle, the muscle is attached near the place of its beginning. With the contraction of this muscle, together with the contraction of the palpebral part, tight closing of the eyelids is carried out.

Lacrimal part of the orbicular muscle of the eye(Horner's muscle) is represented by a deep portion of muscle fibers that begin somewhat posterior to the posterior crest of the lacrimal bone (crista lacrimalis posterior os lacrimale). Then they pass behind the lacrimal sac and are woven into the palpebral fibers of the orbicularis muscle, coming from the anterior lacrimal crest. As a result, the lacrimal sac is covered by a muscle loop, which, when contracting and relaxing during blinking movements, either expands or narrows the lumen of the lacrimal sac. Absorption and promotion of the lacrimal fluid along the lacrimal ducts is also facilitated by the contraction of those bundles of the lacrimal muscle that cover the lacrimal canaliculi.

In raising the upper eyelid and opening the palpebral fissure involved striated- m.levator palpebrae superior and smooth muscle- superior and inferior tarsal or Müllerian muscles. There is no muscle similar to the levator on the lower eyelid. The function of raising the lower eyelid is carried out by a weakly expressed muscle (m. tarsalis inferior) and the lower rectus muscle of the eye, which gives an additional tendon to the thickness of the lower eyelid.

M. levator palpebrae superior - starts in the depth of the orbit, where at the top it departs from the tendon ring (annulus tendineus communis) together with the rectus muscles of the eyeball, goes under the roof of the orbit anteriorly and at the level of the supraorbital edge passes into a wide tendon, which diverge fan-shaped and divide into three departments. The anterior part of the tendon in the form of thin bundles of fibers passes the tarsoorbital fascia and the orbicular muscle, diverges fan-shaped and merges with the subepithelial layer of the skin of the eyelids. back portion penetrates into the upper fornix of the conjunctiva and is attached here. Medium - the most powerful(Muller's muscle) is attached along the upper edge of the cartilage throughout its continuation. In its structure, the Müller muscle is reticulate, only part of its muscle bundles comes perpendicular to the edge of the cartilage, penetrating between the levator fibers and accompanying them in places to the upper edge of the cartilage. In this case, the levator tendon is stratified by smooth muscle fibers. The other part of the fibers approaches in an oblique direction. The third forms a well-defined transverse beam, weaving into the aponeurosis of the levator. Such contact with the levator aponeurosis provides not only elevation, but also prevents wrinkling of the eyelid. The lateral branches of the levator tendon fix it to the periorbit. Contraction of the muscle leads to pulling up simultaneously the skin, tarsal plate and conjunctival fornix. The main muscle is the muscle that lifts the upper eyelid, the auxiliary muscle of Müller lying under it, and when looking up, the frontal and superior rectus. The Muller muscle is innervated by the sympathetic nerve, and the remaining two portions are innervated by the III pair (oculomotor nerve).

With the contraction of the palpebral part of the circular muscle of the eye blinking and slight squeezing of the eyelids. It was established by electromyography that during voluntary blinking movements, the muscle, levator levator lid and orbicularis muscle act reciprocally: the activity of one is accompanied by the passivity of the other. If the upper eyelid slowly descends, then not only the activity of the muscle that lifts it decreases, but the antagonist (circular muscle) also remains passive. However, the general mechanism of closing the eyelids is more complicated due to the combined connection of the orbicular muscle with the mimic muscles on the one hand and the epidermis of the facial skin on the other. As a result of these connections, the eyelids, when closed, move not only up and down, but also in a horizontal direction - inwards, especially the lower one, which plays an important role in the advancement of the lacrimal fluid. When the eyelids close, the palpebral fissure shortens by 2 mm. In addition, the deep part of the palpebral portion of the circular muscle plays a leading role in the mechanism of lacrimal evacuation.

Ligaments of the eyelids

medial and lateral ligaments serve as the main apparatus that attaches various elements of the eyelid to the bone wall of the orbit: the edges of the eyelids themselves, the circular muscle of the eye, the edges of the cartilage and the tarsoorbital fascia. The medial ligament has two legs: front and back. The first in the form of a powerful collagen cord formed by the tendon of the orbicular muscle and merging with it by the collagen fibers of the medial sections of the cartilage and the orbicular fascia, runs in the horizontal direction in front of the lacrimal sac from the inner corner of the eyelids to the anterior lacrimal scallop (upper jaw). The cord is well palpable and becomes visible when the conjunctiva is pulled down, due to the tension of the internal ligament. Its back leg branches slightly away from the angle of the eyelids in the form of a tendon, bends around the lacrimal sac outside and behind and is attached to the posterior lacrimal crest of the lacrimal bone. Thus, the medial ligament covers the lacrimal sac both anteriorly and posteriorly. The lateral ligament of the eyelids, in comparison with the internal one, is poorly developed and is only a suture with a tendon bridge between the outer parts of the orbicular muscle of the upper and lower eyelids. The ligament is reinforced by the collagen fibers woven into it from the outer ends of the cartilage and the tarsoorbital fascia. It also runs horizontally from the outer corner of the eyelids to the bony tubercle of the zygomatic bone - tuberculum orbitae, where it is attached 2-3 mm away from the edge of the orbit.

Cartilage of the eyelid

It is a crescent-shaped plate with pointed edges (during incision in the intermarginal space, it easily splits into 2 plates). The collagen tissue that forms this plate with an admixture of elastic fibers is distinguished by a special cartilaginous density. Therefore, the name cartilage has taken root, although histologically, there are no elements of cartilage here. The pointed ends of the cartilages are firmly connected to each other by a binding of collagen fibers. Collagen fibers running from the edges of the cartilage to the medial and lateral ligaments of the eyelids fix the cartilage to the bony walls of the orbit. The density of cartilage determines its protective “skeletal” function. Cartilage repeats the convex shape of the eyeball. The length of the cartilage of the upper eyelid is 2 cm, the height is 1 cm, the thickness is 1 mm, the cartilage of the lower eyelid is smaller, its height is 5 mm. The anterior surface borders on loose connective tissue, the posterior one is closely connected with the conjunctiva.

In the thickness of the cartilage, modified sebaceous glands - meibomian(on the upper eyelid - 27-30, on the lower - about 20). They have an alveolar structure and secrete a fatty secret. Very short ducts of the alveoli flow into a long common excretory duct. The glands are parallel to each other and perpendicular to the free edge of the eyelids, occupying the entire height of the cartilage. The openings of the ducts open in front of the posterior rib of the eyelid in the form of pores. The secret of the meibomian glands serves as a fatty lubricant, protects the edges of the eyelids from maceration, prevents the transfusion of tears over the edge of the eyelids, contributing to its proper outflow.

Thus, the cartilage is like direct continuation of the tarsoorbital fascia, strongly associated with the orbital edge. This septum (septum orbitae) completely separates the contents of the orbit from the tissues of the eyelids, preventing the spread of pathological processes in depth. The back surface of the eyelids is covered with conjunctiva, which is tightly fused with cartilage, and outside it forms mobile vaults. Deep upper vault and shallower and easily accessible lower vault.

The conjunctiva is a thin, transparent mucous tissue, which in the form of a thin shell covers the entire back surface of the eyelids (tunica conjunctiva palpebrarum), forms deep vaults (fornix conjunctivae superior et inferior) and passes to the eyeball (tunica conjunctiva bulbi) ending at the limbus. In the conjunctiva of the eyelids, in turn, they distinguish the tarsal part - tightly fused with the underlying tissue, and the mobile - orbital, in the form of a fold transitional to the arches.

cartilage conjunctiva covered with a two-layer cylindrical epithelium and contains goblet cells at the edge of the eyelids, and the crypts of Henle at the distal end of the cartilage. Both those and others secrete mucin. Under the epithelium is the reticular tissue tightly soldered to the cartilage. At the free edge of the eyelids, the mucous membrane is smooth, but already 2-3 mm from it, roughness appears, due to the presence of papillae here.

Conjunctiva of transitional fold smooth and covered with 5-6 layer transitional epithelium, also with a large number of mucin-secreting goblet cells. Under the epithelium is loose connective tissue, consisting of elastic fibers and containing plasma cells and lymphocytes. The conjunctiva here is easily displaced and forms folds that facilitate the free movements of the eyeball.

On the border between the tarsal and orbital parts in the conjunctiva are additional lacrimal glands s, similar to the structure and function of the main lacrimal gland: Wolfring - 3 at the upper edge of the upper cartilage and one more below the lower cartilage, and in the area of ​​\u200b\u200bthe arches - Krause. The number of the latter reaches 6-8 on the lower eyelid and from 15 to 40 on the upper one. The blood circulation of the eyelids is carried out by two systems: the system of the internal carotid artery (branches of a. ophthalmica). a.supraorbitalis, a.lacrimalis and the system of the external carotid artery (anastomoses a.facialis and a.maxillaris, a.temporales superfacialis).

From the nasal side, they penetrate into the thickness of both eyelids from the depth of the orbit medial palpebral arteries of the eyelid- upper and lower (a. palpebralis mediales superiores et inferiores) - terminal branches of a. supraorbitalis. From the lateral side, a.palpebralis lateralis departs from a.lacrimalis. In the loose connective tissue layer between the musculocutaneous and tarsal-conjunctival plates of the eyelid, these medial and lateral branches of the palpebral arteries are directed towards each other, merge and form transversely located arterial arches: upper and lower - (arcus tarseus sup. et inf., or arr subtarsalis sup.et inf.). Both arterial arches run along the edges of the eyelid, the upper one is 1-2 mm from the edge of the eyelid, the lower one is 1-3 mm. At the level of the upper edge of the cartilage, a second peripheral arc or arcus tarseus sup is formed. On the lower eyelid, it is not always expressed. Between the peripheral and subtarsal arches there are vertical anastomoses with the arteries of the face. In the vascularization of the lower eyelid and the surrounding area are involved and branches of the infraorbital artery, departing from the maxillary artery (from the system of the external carotid artery). These arcs nourish all the tissues of the eyelids. The veins of the eyelid go according to the arteries, forming two networks: superficial and deep. There are much more anastomoses - with veins of the face and veins of the orbit. Because there are no valves in the veins, blood flows both into the venous network of the face and the orbit and through v.ophthalmica. superior, pouring blood into the cavernous sinus (therefore, there is a high probability of infection entering the cranial cavity). On their way to the orbit, the veins that drain blood from the eyelids also penetrate the orbital muscle. Its spasm in diseases of the eyeball (scrofula) can lead to swelling of the eyelids.

The most important anastomoses of the venous network of the eyelids- with the lacrimal vein (v.lacrimalis) and with the superficial temporal (v.temporalis superfacialis). Of particular importance are anastomoses with v.angularis, passing from the inner canthus and anastomosing with v.ophthalmica superior.

lymphatic system- a network of widely branched lymphatic vessels in both deep and subtarsal layers. Both networks anastomose widely with each other. The regional lymph node draining lymph from the upper eyelid is the anterior one, from the region of the lower eyelid it is the submandibular one.

Eyelid innervation

The III and VII pairs of cranial nerves take part in the motor innervation of the eyelids.

Circular muscle of the eye- a branch of the facial nerve (VII pair), its motor fibers provide closure of the eyelids. The facial nerve has a mixed composition: includes motor, sensory and secretory fibers that belong to the intermediate nerve, which is closely related to the facial nerve. The motor nucleus of the nerve is located in the lower part of the pons varolii at the bottom of the IV ventricle, bending around the nucleus of the abducens nerve localized from above, forms the knee (genu n. Facialis) and goes to the base of the brain in the cerebellopontine angle. Then, through the internal auditory opening, it enters the canalis facialis, in which it makes two turns with the formation of a knee and a knee node (geniculum et ganglium gen.). A large stony nerve (n. petrosus major) originates from the knee node, carrying secretory fibers to the lacrimal gland, extending from a special lacrimal nucleus, and the facial nerve itself exits the canal through the foramen stilomastoideum, giving off branches n at this level. auricularis posterior et r. digastricus. Then, with a single trunk, it pierces the parotid gland and divides into upper and lower branches, which give off multiple branches, including the circular muscle of the eye. The muscle that lifts the upper eyelid is innervated by the oculomotor nerve (III pair), only its middle part, i.e. Müller's muscle is a sympathetic nerve.

Nucleus of the oculomotor nerve located at the bottom of the sylvian aqueduct. The oculomotor nerve exits the skull through the superior orbital fissure, attaching sympathetic (from the plexus of the internal carotid artery) and sensory fibers (from n.ophthalmicus), passes through the cavernous sinus. In the orbit, within the muscular infundibulum, it divides into superior and inferior branches. The upper, thinner branch, passing between the upper rectus muscles and the muscle lifting the upper eyelid, innervates them.

Sensitive nerves to the upper eyelid and forehead skin come from the ophthalmic nerve (n.ophthalmicus) of the 1st branch of the trigeminal nerve, which exits through the superior orbital fissure and is divided into three main branches: n.lacrimalis, n.frontalis et n.nasociliaris. In the innervation of the skin of the eyelids, n.frontalis takes the main part., in the medial region of the upper eyelid, its branches n.supraorbitalis et n.supratrochlearis go under the skin. The ophthalmic nerve supplies sensitive innervation to the skin of the forehead, the anterior surface of the scalp, upper eyelid, inner corner of the eye, back of the nose, the eyeball itself, the mucous membranes of the upper part of the nasal cavity, the frontal and ethmoid sinuses, and the meninges. The lower eyelid receives sensitive innervation from n.infraorbitalis, extending from the 2nd branch of the trigeminal nerve (n.maxillaris). maxillary nerve exits the cranial cavity through a round hole and innervates the dura mater, skin, cartilage and conjunctiva of the lower eyelid (except for the innermost and outer corners of the palpebral fissure), the lower half of the lacrimal sac and the upper half of the nasolacrimal duct, the skin of the anterior part of the temporal region, the upper part of the cheek , wings of the nose, as well as the upper lip, upper jaw (and the teeth located on it), the mucous membranes of the back of the nasal cavity and the maxillary sinus.

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