Eye diseases. The structure of the soft tissues of the eye (the most important)

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Eye diseases. The structure of the soft tissues of the eye (the most important)

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2. The structure of the soft tissues of the eye

The superior, inferior, external and internal rectus and superior and inferior oblique muscles related to the oculomotor muscles, as well as the muscle that lifts the upper eyelid, and the orbital are located in the orbit. Muscles (except for the inferior oblique and orbital) start from the connective tissue ring that surrounds the visual opening, and the inferior oblique muscle from the inner corner of the orbit. The muscles are separated from the limbus by an average of 5,58,0 mm. In newborns, this value is 4,05,0 mm, and in children aged fourteen years, 5,07,5 mm. The superior and inferior oblique muscles are attached to the sclera 16 mm from the limbus, the external rectus turns the eye outward, the internal inwards, the superior moves upwards and inwards, the inferior downwards and inwards.

The eyelids cover the front of the eye socket. The connection of the free edges of the lower and upper eyelids with each other occurs through external and internal adhesions. There is a variation in the width and shape of the palpebral fissure. Normally, the edge of the lower eyelid should be 0,51,0 mm below the corneal limbus, and the edge of the upper eyelid should cover the cornea by 2 mm. The skin of the eyelids is thin, delicate, poor in fatty tissue, loosely connected with the underlying parts, the underlying vessels shine through it.

The muscles of the eyelids are poorly developed. The muscular layer of the eyelids is represented by a circular muscle, innervated by the facial nerve and providing closure of the eyelids. Under the muscle is cartilage, in the thickness of which the meibomian glands are located, translucent in the form of yellowish radial stripes. The back surface of the eyelids is covered with a connective sheath. On the front edge of the eyelids there are eyelashes, near the root of each eyelash there are sebaceous and modified sweat glands. The lifting of the upper eyelid is carried out with the help of the muscle of the same name, which is innervated by the branches of the oculomotor nerve.

The blood supply to the eyelids is carried out by the external branches of the lacrimal artery, the internal arteries of the eyelids and the anterior ethmoidal artery. The connective sheath, the conjunctiva, covers the eyelids from the inside, passes to the sclera and continues in an altered form to the cornea. There are three sections of the conjunctiva: cartilage (or eyelids), transitional fold (or fornix) and the eyeball. All three sections of the conjunctiva with closed eyelids form a closed slit cavity, the conjunctival sac.

The blood supply of the conjunctiva is carried out by the arterial system of the eyelids and the anterior ciliary arteries. The veins of the conjunctiva accompany the arteries, the outflow of blood occurs in the system of facial veins and through the anterior ciliary veins of the orbit. The conjunctiva of the eye has a well-developed lymphatic system.

The lacrimal organs consist of a tear-producing and tear-removing apparatus. The tear-producing apparatus includes the lacrimal gland and Krause's glands. The lacrimal gland is located in the bony cavity of the upper outer part of the orbit. Twenty or more (up to thirty) excretory ducts of the gland open into the lateral part of the superior conjunctival fornix.

Author: Shilnikov L.V.

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