THE LACRIMAL BODIES

From Big Medical Encyclopedia

THE LACRIMAL BODIES [apparatus lacrimalis (PNA, BNA), organa lacrimalia (JNA)] — the pair bodies which are producing the lacrimal liquid (tear) and taking away it in a nasal cavity. The lacrimal bodies (the lacrimal device, T.) consist of the lacrimal gland and slezootvodyashchy ways (fig. 1).

Fig. 1. Topography of the lacrimal bodies: 1 — the lacrimal gland; 2 — the lacrimal meat; 3 and 4 — top and bottom the lacrimal tubules; 5 — a dacryocyst; 6 — the lacrimonasal channel; 7 — the lower nasal sink.

The embryology

Orbital, or orbital, a part of the lacrimal gland is put at an embryo at the age of 8 weeks. By the time of the birth the lacrimal liquid is almost not emitted since the lacrimal gland is still insufficiently developed (90% of children only by 2nd month of life have an active slezootdeleniye). Formation of slezootvodyashchy ways begins with 6 weeks of embryonal life. From the orbital end of a lacrimonasal furrow plunges into connecting fabric epithelial tyazh, to-ry it otshnu-rovyvatsya gradually from an initial epithelial cover of the person and by 10th week reaches an epithelium of the closing nasal stroke. On the 11th week there is a transformation of a tyazh into the channel covered by an epithelium, to-ry at first comes to an end blindly. Its opening in a nasal cavity happens in 5 months Apprx. 35% of children is born with the outlet opening of a nasal duct closed by a membrane; usually the membrane is broken off in the first days after the birth.

The anatomy, histology

the Lacrimal gland (glandula lacrimalis) consists of two parts: upper, or orbital (orbital part, T.; pars orbitalis), and lower, or palpebral (century part, T.; pars palpebralis). They are divided by a wide sinew of the muscle raising an upper eyelid (m. levator palpebrae sup.). Orbital part of the lacrimal gland is located in a pole of the lacrimal gland of a frontal bone on a lateral and upper wall of an eye-socket (fossa glandulae lacrimalis). The sagittal size of gland is 10 — 12 mm, frontal — 20 — 25 mm, thickness — 5 mm. Normal an orbital part of gland is unavailable to external examination. It has from 3 to 5 output tubules passing between segments of a palpebral part of the lacrimal gland and opening in the upper arch conjunctivas (see) sideways at distance of 4 — 5 mm from the upper edge tarzalny • plates (an upper cartilage of a century, T.). A palpebral part of the lacrimal gland is much less than orbital, is located below it under an upper fornix conjunctiva. The size of its 9 — 11x7 — 8 mm, thickness is 1 — 2 mm. A number of output tubules of a palpebral part of the lacrimal gland falls into output tubules of an orbital part, and 3 — 9 tubules open independently. Multiple output tubules of the lacrimal gland remind a shower, from openings to-rogo a tear comes to a conjunctival sac.

The lacrimal gland is held by own sheaves (lig. suspenso-rium Soemmerringii, lig. retinens glandulae lacrimalis), the eye-sockets which are attached to a periosteum of an upper wall. Gland is strengthened also by Lokvud's team and a muscle raising an upper eyelid (see. Eyelids ).

Blood supply of the lacrimal gland is carried out at the expense of the lacrimal artery (a. lacrimalis) — a branch of an eye artery. Outflow of blood happens through the lacrimal vein (v. lacrimalis).

Fig. 2. The diagrammatic representation of an innervation of the lacrimal gland (the way of secretory fibers is designated in black color): 1 — the lacrimal gland; 2 — a connecting branch of a malar nerve with the lacrimal nerve; 3 — the lacrimal nerve; 4 — a malar nerve; 5 — a pterygopalatine node (the place of switching of secretory fibers); 6 — a big stony nerve; 7 — the I branch of a trifacial (optic nerve); 8 — the II branch of a trifacial (a maxillary nerve); 9 — the III branch of a trifacial (a mandibular nerve); 10 — a trigeminal node; 11 — a facial nerve; 12 — a node of kolenets.

The lacrimal gland is innervated by branches of an optic and maxillary nerve (see. Trifacial ), branches facial nerve (see) and sympathetic fibers from an upper cervical node. The main role in regulation of secretion of the lacrimal gland belongs to the parasympathetic fibers which are a part of a facial nerve (fig. 2). The center of a reflex slezootdeleniye is in myelencephalon (see). Besides, there is a number of the vegetative centers, the irritation to-rykh strengthens a slezootdeleniye.

The lacrimal gland belongs to difficult and tubular serous to glands (see), on structure it is similar to a parotid gland (see). Output tubules of big caliber are covered by a two-layer cylindrical epithelium, and smaller caliber — a single-layer cubic epithelium. In addition to the main lacrimal gland, there are small tubular additional lacrimal pieces of iron (glandulae lacrimales accesso-riae) located in a fornix conjunctiva — Krause's glands (conjunctival glands, T.) and at the upper edge of a cartilage a century, in an orbital part of a conjunctiva — glands Wal-deyera. In an upper fornix conjunctiva there are 8 — 30 additional pieces of iron, in lower — 2 — 4.

Slezootvodyashchy ways begin the lacrimal stream (rivus lacrimalis). It is a capillary crack between a back edge of a lower eyelid and an eyeglobe. On the lacrimal stream the tear flows down to the lacrimal lake (lacus lacrimalis) located at a medial corner of an eye. At the bottom of the lacrimal lake there is a small eminence — the lacrimal meat (caruncula lacrimalis). The lower and upper lacrimal openings (puncta lacrimalia) are shipped in the lacrimal lake. They are at tops of the lacrimal nipples (papillae lacrimales) and normal have diameter to 0,5 mm. The lower and upper lacrimal tubules (canaliculi lacrimales) originate from the lacrimal openings, to-rye go respectively up and down throughout 1,5 mm, and then, being bent at right angle, fall into a dacryocyst, more often the general mouth. On site their confluences the bosom — Meyer's (sinus Meyeri) sine from above is formed, there are folds of a mucous membrane: from below — Gushke's (valvula Huschke) valve, from above — Rozenmyuller's (valvula Ro-senmiilleri) valve. Dltsna of the lacrimal tubules of 6 — 10 mm, a gleam — 0,6 mm. The dacryocyst (saccus lacrimalis) is located behind a medial sheaf a century (lig. palpebrale med.) in a pole of the lacrimal ^ешка (fossa sacci lacrimalis), the formed frontal shoot of an upper jaw and the lacrimal bone. Surrounded with friable cellulose and a fascial case, the arch of a bag on Vs rises over a medial sheaf a century, and below the dacryocyst passes into a nasal duct (ductus nasolacrimalis). Length of a dacryocyst is 10 — 12 mm, width is 2 — 3 mm. Walls of a bag consist of the elastic and interwoven into them muscle fibers of a century part of a circular muscle of an eye (pars palpebra-lis m. orbicularis oculi), and also the lacrimal part of a circular muscle of an eye (pars lacrimalis m. orbicularis oculi) or muscles of a dacryocyst of Horner (m. sacci lacrimalis Horneri), reduction the cut promotes suction of a tear. The mucous membrane of a dacryocyst and nasal duct has character of adenoid fabric, is covered cylindrical, places by a ciliary epithelium. In lower parts of a nasal duct the mucous membrane is surrounded with dense venous network as cavernous fabric.

A nasal duct, an upper part to-rogo it is put into the bone lacrimonasal canal, takes place in a lateral wall of a nose. The nasal duct is longer than the bone lacrimonasal channel, length of a nasal duct from 10 to 24 mm, width of 3 — 4 mm. Exit in a nose has a fold of a mucous membrane — the lacrimal valve of Gasner (valvula lacrimalis Has-neri). The nasal duct under the front end of the lower nasal sink at distance of 30 — 35 mm from an entrance to a nasal cavity (from nostrils) in the form of the wide or slotted opening opens. Sometimes the nasal duct passes in the form of a narrow tubule in a mucous membrane of a nose and opens away from an opening of the bone lacrimonasal channel. Two last anatomic options of a structure of outlet opening of a nasal duct as well as sharply expressed anatomic versions of the numerous valves, crests and sine located on the course of the lacrimal tubules, a dacryocyst and a nasal duct (Gushke, Rozenmyuller, Gasner's valves, Meyer's sine, etc.), can break the mechanism of an active slezootvedeniye in a nasal cavity and promote development of inflammatory processes in slezootvodyashchy ways.

The physiology

the Tear developed by the lacrimal glands represents transparent, with alkalescent reaction liquid, average ud. its weight 1,008. It contains 98,2% of water, the rest protein, urea, sugar, sodium, potassium make, chlorine, epithelial cells, slime, fat, bacteriostatic enzyme lysozyme (see).

The tear is of great importance for normal function of an eye. The thin coat of the liquid covering a front surface of a cornea along with other factors, provides ideal smoothness and transparency of a cornea and consequently, and the correct refraction of rays of light its front surface. The tear promotes also clarification of a conjunctival sac from microbes and foreign bodys.

Additional lacrimal pieces of iron allocate 0,5 — 1,0 ml of a tear a day, i.e. it is so much how many it is required for moistening and a surface cleaning of an eye; orbital and palpebral parts of the lacrimal gland get into gear only at irritation of an eyeglobe, nasal cavity, during the crying etc. During the crying it can be allocated up to 2 teaspoons of the lacrimal liquid. Slezootvedeniye is provided with the following factors: capillary suction of liquid in the lacrimal openings and the lacrimal tubules; reduction and relaxation of a circular muscle of an eye, especially its lacrimal part (Horner's muscle) that creates negative pressure in slezootvodyashchy ways; existence of folds of a mucous membrane of the slezootvodyashchy ways playing a role of fluid valves.

Methods of inspection

begin Inspection of the patient with acquaintance with the anamnesis of a disease. Only a palpebral part of the lacrimal gland is available to survey, to-ruyu examine at turn of the studied eye of a knutra and from top to bottom and an ectropion of an upper eyelid. An orbital part of the lacrimal gland is investigated by means of a palpation. At external examination of slezootvodyashchy ways pay attention to existence of a slezostoyaniye, situation and expressiveness of the lacrimal openings, especially lower, a condition of a conjunctiva, skin a century, areas of a dacryocyst; on existence and character separated from a conjunctival sac, the lacrimal openings and a dacryocyst.

A research with slit lamp (see) apply to diagnosis of pathology of the lacrimal openings (dislocation, an ectropion etc.) after preliminary instillation in a conjunctival sac of 3% of solution of colloid silver.

Functional researches include canalicular test and nasal test. Canalicular test (see) make for check of prisasyvayushchy function of the lacrimal openings, tubules and a dacryocyst. Nasal make for definition of degree of passability of slezootvodyashchy ways. After instillation in a conjunctival sac of 2 drops of 3% of solution of colloid silver enter into a nose under the lower nasal sink the probe with the moistened cotton wool. Test is positive at emergence of paint on cotton wool in the first 5 min., slowed down — at its detection in 6 — 20 min. and negative if paint appears after 20 min. or it is not found at all.

Sounding and washing of slezootvodyashchy ways make with the diagnostic purpose, after anesthesia of 0,25% solution of Dicainum and expansion of the lacrimal opening the conic probe. Normal the cylindrical probe Boumena-No. 1 freely passes on the course of the lacrimal tubule to an internal wall of a dacryocyst. Sounding of a nasal duct for the purpose of diagnosis is not made. Establish by washing of slezootvodyashchy ways their passive passability for liquid. The blunt-pointed cannula which is put on the syringe is carefully entered on the lacrimal tubule into a dacryocyst. Normal liquid (0,02% solution of Furacilin, isotonic solution of sodium chloride, etc.) follows from the corresponding nostril a stream in a tray. At an obliteration of the lacrimal ways liquid follows from opposite or same lacrimal opening in a conjunctival sac.

The X-ray analysis of slezootvodyashchy ways with contrasting allows to obtain the most valuable information on level and extent of disturbance of passability of slezootvodyashchy ways (see. Dakriotsistografiya ).

The rhinologic research allows to reveal various patol. changes and anatomic features of a structure of a nasal cavity and his adnexal bosoms (okolonosovy bosoms, T.), and also to choose an optimal variant of the subsequent treatment.

Pathology

Allocate pathology of the lacrimal gland and pathology of slezootvodyashchy ways.

Pathology of the lacrimal gland

Malformations. Absence or underdevelopment of the lacrimal gland is characterized by lack of a tear that is especially expressed during the crying. Treatment is not required since additional lacrimal pieces of iron develop enough a tear for moistening and a surface cleaning of an eye. It is necessary to preserve an eye against infection.

Shift of the lacrimal gland arises at weakness of the sheaves supporting gland. Such gland in the form of painless education is probed under skin of an upper eyelid and a lateral corner of an eye. It is easily set by a finger and again drops out. Treatment — operational, is directed to strengthening of the lacrimal gland in the bed. Forecast favorable.

Damages the lacrimal gland are rare, are observed usually at damages eye-sockets (see), an upper eyelid (see. Eyelids ). An operative measure (removal of gland) is required only when there is a considerable destruction of gland, its loss in a wound.

Diseases. Functional frustration of the lacrimal gland are shown in the form of hyperfunction — the raised slezootdeleniye (dacryagogue, lacrimation) at a normality of slezootvodyashchy ways. Various reflex irritations, frustration of its innervation can be the cause of hyperfunction of the lacrimal glands. In some cases the reason does not manage to be established. Reflex dacryagogue can be caused by bright light, wind, cold, patol. process in a nasal cavity, etc. If dacryagogue resistant, then is made by injections of 96% of alcohol in the lacrimal gland, blockade of a pterygopalatine node, electrothermic coagulation (see. Diathermocoagulation ) or partial adenectomy. The forecast favorable at elimination of a cause of illness.

Hypofunction of the lacrimal gland is one of manifestations of a syndrome of Shegren (see. Shegrena syndrome ).

Inflammatory diseases of the lacrimal gland in the isolated look meet seldom, more often the inflammation develops as a complication at various inf. diseases, napr, at flu, scarlet fever (see. Dacryadenitis ).

Tumors the lacrimal gland meet seldom. Distinguish benign and malignant tumors.

From high-quality mixed meet more often tumors (see). Tumoral process is shown by unilateral gradual painless increase in gland, small shift of an eye of a knutra and from top to bottom. Visual disturbances are rare. Enclavomas in 4 — 10% of cases malignizirutsya.

Besides, carry a cyst (dacryops) to benign tumors, edges develops either in gland, or from its output channels after an injury or an inflammation. It represents the translucent, painless tumor acting at the considerable sizes from under the outer edge of an eye-socket.

Treatment of a cyst of the lacrimal gland consists in its excision from a conjunctival sac or diathermocoagulation. Forecast favorable. Other tumors of the lacrimal gland are subject to removal together with gland.

Malignant tumors of the lacrimal gland (preferential adenocarcinomas), by data A. I. Pachesa et al. (1980), make 68 — 76% of all new growths of this localization. Sprouting surrounding fabrics, malignant tumors fix an eyeglobe, cause severe pains, break sight, metastasize in the remote bodies.

At a malignancy of a benign tumor or primary and malignant tumor make ekzenteration of an eye-socket (see) with the subsequent radiation therapy (see).

Pathology of slezootvodyashchy ways

to the Most frequent a wedge, display of the inborn or acquired pathology of slezootvodyashchy ways is constant dacryagogue.

Malformations. The inborn closing of the mouth of a nasal duct leading to development in newborns meets more often dacryocystitis (see). Inborn lack, shift, narrowing or an obliteration of the lacrimal opening, lack of the lacrimal tubule, a fistula of a dacryocyst are in rare instances noted. At disturbance of a slezoottok the operational treatment directed to creation of a way of assignment of a tear to a nasal cavity is shown.

Damages. Ruptures of the lacrimal tubules are observed at an injury of a medial part a century; timely surgical treatment of a wound the ophthalmologist is necessary. Damages of a dacryocyst and a nasal duct meet at injuries with damage of fabrics of a medial corner of an eye and at changes of a medial wall of an eye-socket, nasal bones and a frontal shoot of an upper jaw more often. As a rule, these damages are distinguished late, at a complication by a purulent dacryocystitis. Treatment operational.

Diseases. Patol. changes of the lacrimal openings in the form of the shift, an ectropion, narrowing, an obliteration usually result from damages or inflammatory diseases of a conjunctiva a century. Most often the ectropion of the lower lacrimal opening meets. Treatment operational (see. Blepharoplasty ).

The inflammation of the lacrimal tubule (dakriokanalikulit) arises for the second time against the background of inflammatory processes of a conjunctiva more often. Skin in the field of tubules inflames. Dacryagogue, mucopurulent allocations from the lacrimal openings are noted. Strong expansion of the lacrimal tubule owing to its filling with pus and fungal concrements is characteristic of fungal dakriokanalikuli-t. Treatment dakriokanat ikulit conservative, depends on the reasons which caused it. At fungal dakriokanalikulita make splitting of the lacrimal tubule and removal of concrements with the subsequent greasing of a cavity of the lacrimal tubule of 5% spirit solution of iodine.

Sometimes the atony of the lacrimal tubules which is characterized by negative canalicular test at a normality of the lacrimal opening and a free gleam of the lacrimal tubule meets. Treatment — darsonvalization of area of the lacrimal tubule, an ionophoresis with calcium chloride and novocaine.

The stenosis and obliteration of the lacrimal tubule can result from an inflammation or damage of tubules. Treatment — plastic recovery of a gleam of a tubule.

An inflammation of a dacryocyst — see. Dacryocystitis .

The stenosis and an obliteration of a nasal duct resulting from it an inflammation or damage are characterized by the slowed-down or negative nasal test at positive canalicular; often lead to development of a dacryocystitis. At a stenosis treatment is begun with trial sounding of a nasal duct and washing with its solutions containing proteolytic enzymes. At an obliteration of a nasal duct, and also at unsuccessfulness of conservative treatment of a stenosis perform operation of imposing of an anastomosis between a dacryocyst and a nasal cavity that provides recovery of outflow of a tear in a nasal cavity (see. Dacryocystorhinostomy ).

Tumors slezootvodyashchy ways meet seldom. At benign tumors (fibromas, papillomas, polyps) the wedge, a picture на^ remembers hron. dacryocystitis. Treatment operational: an oncotomy with simultaneous carrying out a dacryocystorhinostomy. Forecast favorable. The malignant tumor (a carcinoma, sarcoma) can burgeon in skin, a nasal cavity, paranasal sinuses. Treatment operational in combination with radiation therapy. At late detection of a tumor the forecast adverse.

Operations on the slezootvodyashchy ways

the Purpose of operative measures at disturbances the slezootvede-niya is creation of the resistant message between a dacryocyst and a nasal cavity. Apply dacryocystorhinostomy (see) in various modifications with use of outside and intranasal approaches. At these operations one of the difficult and responsible moments is formation of a bone window in the lacrimal pole. The advanced method of endonasal operations on the slezootvodyashchy ways using the ultrasonic equipment considerably facilitated carrying out this stage of operation. So, the operations which are carried out by means of the knife raspatory and a saw working from the supersonic generator take place much quicker, with a smaller operational injury and considerable reduction of terms of postoperative treatment. Modern endonasal operations on the slezootvodyashchy ways yield good cosmetic and functional results, especially at recurrent dacryocystites, the combined injuries of a nose, eye-socket and slezootvodyashchy ways, at bilateral pathology of slezootvodyashchy ways, etc.



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V. G. Beloglazov.

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