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Anatomy of the paranasal sinuses

The paranasal sinuses, sinus paranasalis, are located in the bones of the facial and brain skulls and communicate with the nasal cavity. They are formed as a result of the ingrowth of the mucous membrane of the middle nasal passage into the spongy bone tissue. In fig. 2.1.4 presents a diagram of the development of the paranasal sinuses in the age aspect.

Phylogenetically, the paranasal sinuses are derivatives of the ethmoid labyrinth (Speransky V.S., 1988), the structure of which is most complex in animals with a well-developed sense of smell (macromatics).

In clinical practice, it is customary to subdivide the paranasal sinuses into the lower ones, which include the maxillary sinuses, and the upper ones (frontal, ethmoid labyrinth and sphenoid sinus). Among the latter, in turn, the anterior (frontal sinuses and anterior cells of the ethmoid labyrinth) and the posterior (posterior cells of the ethmoid labyrinth and sphenoid sinus) stand out. The topographic and anatomical location of the sinuses is shown in Fig. 2.1.5 and 2.1.6.

The frontal sinus, sinus frontalis, is a paired cavity located in the frontal bone. The frontal sinus develops from lists of the ethmoid cell that has invaded the frontal bone. The degree of development of the frontal sinuses is subject to large individual fluctuations. Sometimes frontal sinuses may be completely absent. The developed frontal sinus is located in the lower part of the scales of the frontal bone and continues into its horizontal plate.

Distinguish between the anterior (or frontal) wall, the posterior (or brain), the lower (or orbital-nasal) and the internal (or inter-axial septum). The front wall of the frontal sinus is the thickest, especially in the area of ​​the superciliary arches. It is bounded below by the edge of the orbit; its upper boundary is unstable. The lower wall, or the bottom of the sinus, is divided into the nasal and orbital parts. The back wall (brain) is a very thin, compact, spongy-free plate. It is the site of the most frequent transition of the inflammatory process from the frontal sinus to the cranial cavity. The inner wall (interstitial septum) can be very thin and have dehiscence, but there are cases when the interstitial septum reaches a significant thickness. The frontal sinus communicates with the nasal cavity by the fronto-nasal canal, which is a sinuous narrow fissure 12 to 16 mm long and 1 to 8 mm wide. The channel ends in the anterior section of the lunar fissure of the middle nasal passage.

The maxillary sinus, sinus maxillaris, is located in the body of the upper jaw and is the largest airway in the skull. The shape of the maxillary sinus is usually compared with a trihedral or tetrahedral pyramid. The average sinus volume ranges from 15 to 40 cm3. The complete absence of sinus is extremely rare. The upper wall of the maxillary sinus is partly the lower wall of the orbit. This is the thinnest sinus wall. The front wall of the maxillary sinus extends from the lower orbital edge of the orbit to the alveolar process of the upper jaw. The medial wall of the sinus (nasal) is simultaneously the outer wall of the nasal cavity. In the front of it passes the nasolacrimal canal. An outlet of the maxillary sinus, ostium maxillare, is located posterior to the protrusion of the nasolacrimal canal at the highest sinus site. The size of the hole ranges from 2 to 9 mm in length and from 2 to 6 mm in width. If there is an additional hole, the latter is located posteriorly and downward from the main one. The posterior wall of the maxillary sinus corresponds to the maxillary tubercle and its posterior surface faces the pterygopalatine fossa. The lower wall, or the bottom of the maxillary sinus, is subject to significant variations. Of practical importance is the position of the bottom of the maxillary sinus in relation to the nasal cavity. Until the age of 14, the level of the sinus floor coincides with the level of the nasal cavity in only 15% of cases, and in 85% of the sinus floor is located above the bottom of the nasal cavity. In adults, on the contrary, only in 26% of the sinus fundus is located above the fundus of the nasal cavity, at the same level with it - in 27% and lower - in 47% (D.E. Tanfiliev, 1964).

The ethmoid labyrinth, labyrinthus ethmoidalis, unlike other paranasal sinuses, is a complex multicameral cavity that fully corresponds to the size of the ethmoid bone itself, os ethmoidale. The latter is located in the sagittal direction between the frontal and sphenoid sinuses and consists of trellised cells and shells. In the ethmoid bone, a middle, vertically located perpendicular plate is distinguished, and two lateral parts, in which the cells of the ethmoid labyrinth are enclosed, connected at the top of the ethmoid, or sieve, plate. The optic nerve passes close to the ethmoid sinuses.

The sphenoid sinus, sinus sphenoidalis, like the frontal, is a paired cavity formed as a result of tissue resorption in the body of the sphenoid bone. The size of the sinus is variable. In some individuals, it happens in the form of a small cavity or even is absent, while in others it occupies the entire body of the sphenoid bone. The bottom of the sinus forms the nasopharynx. The front wall is the thinnest, has a hole, ostium sphenoidalis, which connects the sinus to the upper nasal passage. Canalis caroticus passes in the side wall, and here the sinus borders on the cavernous sinus, next to which the cranial nerves III, IV and VI pass. The upper wall of the sinus varies in thickness from tissue paper to 7-15 mm. It faces the cranial cavity and is associated with three cranial fossae. The upper wall is a wedge-shaped platform, planum sphenoidale, bounded by a trellised plate in front and a wedge-shaped protrusion at the back. The wedge-shaped platform is sometimes elevated due to the expansion (pneumosinus) of the sphenoid sinus.

In the upper lateral part of the wall are the roots of the small wings of the sphenoid sinus with an opening of the optic nerves. Tractus nervi olfactoris also passes here, and behind is the Turkish saddle with the pituitary gland, which is located between the two trunks of the internal carotid artery, which form their bend here. Part of the frontal lobe of the brain with the olfactory gyrus is adjacent to the upper wall.

The mucous membrane of the nasal cavity and paranasal sinuses. The nasal cavity and paranasal sinuses, with the exception of the vestibule of the nose, are lined with a mucous membrane covered in a multi-row prismatic ciliated epithelium in regio respiratoria, and a multi-row olfactory epithelium in hegio olfactoria.

The main morphofunctional units of the epithelium of the respiratory region are ciliated, intercalated and goblet cells (Fig. 2.1.7). Ciliated cells have on their surface 50-200 cilia 5-8 μm long and 0.15-0.3 μm in diameter (G. Richelman, A.S. Lopatin, 1994). Each cilium has its own motor device - an axonem, which is a complex complex consisting of 9 pairs (doublets) of peripheral microtubules located in the form of a ring around two unpaired central microtubules (Fig. 2.1.8). The movement of the cilia is carried out due to the myosin-like protein contained in them (Ya.A. Vinnikov, 1979). The frequency of beating cilia - 10-15 strokes per minute. The motor activity of the cilia of the ciliated epithelium provides movement of the nasal secretion and particles of dust and microorganisms settled on it towards the nasopharynx from the vestibule of the nose towards the choanas, and in the sinuses from their bottom towards the excretory anastomosis. Only in the very front sections of the nasal cavity, at the front ends of the lower nasal concha, the mucus flow is directed to the entrance to the nose. In general, a particle that has fallen on the surface of the mucous membrane passes from the front of the nasal cavity to the nasopharynx in 5-20 minutes (G. Richelman, A.S. Lopatin, 1994).

Under the influence of various adverse factors (aerosols, toxins, concentrated solutions of antibiotics, changes in ph to the acid side, lowering the temperature of the inhaled air, as well as the presence of contact between the opposite surfaces of the ciliated epithelium), the movements of the cilia slow down and may completely stop.

Normally, ciliated cells are renewed every 4-8 weeks (FSHerson, 1983). When exposed to pathological factors, they quickly undergo degeneration.

Insertion cells, located between the ciliated, have on their surface facing the lumen of the respiratory organ, 200-400 microvilli. Together with ciliated cells, insertion cells carry out and regulate the production of periciliary fluid, determining the viscosity of the secretion of the respiratory tract.

Goblet cells are modified cylindrical epithelial cells and are unicellular glands that produce viscous mucus (CBBaslanum, 1986).

In the own plate of the mucous membrane are glands that produce serous and mucous secretions. In secret, covering the respiratory tract, incl. the nasal cavity, two layers are distinguished: a less viscous periciliary, adjacent to the surface of epithelial cells and a more viscous upper one, located at the level of the tips of the cilia (MAReissing et al., 1978; MAKaliner et al., 1988).

Respiratory and mucous cells form the so-called mucociliary apparatus, the normal functioning of which ensures capture, enveloping with mucus and the movement of most particles with a diameter of up to 5 - 6 microns, including particles containing viruses, bacteria, aerosols from the nasal cavity to the nasopharynx, from where they spit or are swallowed. Impaired mucociliary function is considered as one of the important factors contributing to the introduction of an infectious pathogen into the mucous membrane, giving rise to the development of rhinitis and rhinosinitis (Drettner B., 1984).

In the connective tissue layer of the nasal mucosa, lymphatic follicles are constantly found.

The olfactory epithelium in humans occupies a very small surface in the region of the upper and partially middle nasal concha, as well as in the posterior-upper part of the nasal septum (Khilov K.L., 1960).
It was previously believed that the area of ​​the olfactory zone is 10 cm (Brunn A., 1892). However, according to Friedmann J., Osborn DA (1974), its area does not exceed 2 - 4 cm2. This must be taken into account during rhinosurgical interventions, as loss of smell not only deprives a person of a sense of smell, which reduces the quality of his life, but can be dangerous in some specialties. The olfactory epithelium does not line the olfactory region of the nose with a continuous field. The boundary line between the olfactory and respiratory epithelium often acquires a very complex configuration due to the wedging of the islets of the ciliated epithelium (AA Bronstein, 1977).

The multilayer olfactory epithelium is much higher than the respiratory one. Olfactory cells belong to the so-called primary sensory receptor cells. According to modern views, they are evolutionarily modified flagellum cells (Ya.A. Vinnikov, 1979). At the upper pole of the olfactory cell, which has a fusiform shape, there is a spherical thickening, first described by Ya.A. Vinnikov and L.K. Titova in 1957 and called them the olfactory mace. At the top of the mace is a bundle of flagella, or microvilli, extending to the free surface of the epithelium, providing contact of the receptor cell with the external environment (Fig. 2.1.9). A thin central process departing from the lower pole of the olfactory cell has a structure characteristic of axons. It is then included in the structure of the serene nerve, in which it flows into the olfactory bulb of the forebrain through lamina cribrosa. Receptor cells interspersed with supporting and numerous tubular-alveolar mucous cells, first described by Bowman in 1847. These cells, secreting a protein-polysaccharide secretion, are involved in the formation of a layer of olfactory mucus, which is necessary for adsorption of odorous molecules into the nasal cavity (Bronstein A. A., 1977).

The mucous membrane of the nasal cavity is very rich in blood vessels located in the superficial parts of the mucosa, directly under the epithelium, which helps to warm the inhaled air. Arteries and arterioles of the nasal cavity are characterized by significant development of the muscular membrane. The muscular membrane in the veins is also well developed. In the mucous membrane of the lower nasal concha, there are cavernous venous plexuses.

The mucous membrane of the paranasal sinuses has the same structure as the respiratory region of the nasal cavity, with the only difference being that it is much thinner, poorer in glands, and does not have a cavernous layer. Its connective tissue layer is also much thinner than in the nasal cavity.

Blood supply to the nose and paranasal sinuses.

Arteries. Blood supply to the nose and paranasal sinuses is carried out from the system of the external and internal carotid arteries (Fig. 2.1.10). The main blood supply is provided by the external carotid artery through a. maxillaris and its main branch a. sphenopalatina. It enters the nasal cavity through the pterygopalatine opening, accompanied by the same vein and nerve, and immediately after its appearance in the nasal cavity gives the branch to the sphenoid sinus. The main trunk of the pterygopalatine artery is divided into the medial and lateral branches, vascularizing the nasal passages and concha, maxillary sinus, ethmoid cells and nasal septum. From the internal carotid artery departs a. ophthalmica, entering into orbit through foramen opticum and giving aa. ethmoidales anterior et posterior. From the orbit, both ethmoid arteries, accompanied by the same nerves, enter the anterior cranial fossa through the corresponding openings on the medial wall of the orbit. The anterior ethmoid artery in the region of the anterior cranial fossa gives off a branch - the anterior meningeal artery (a. Meningea media), which supplies the dura mater in the anterior cranial fossa. Then her path continues into the nasal cavity, where she penetrates through an opening in the trellis plate next to the cockscomb. In the nasal cavity, it provides blood supply to the upper anterior part of the nose and is involved in the vascularization of the frontal sinus and the anterior cells of the ethmoid labyrinth.

The posterior ethmoid artery after perforation of the ethmoid plate is involved in the blood supply to the posterior ethmoid cells and partially to the side wall of the nose and nasal septum.

When describing the blood supply to the nose and paranasal sinuses, it is necessary to note the presence of anastamoses between the system of the external and internal carotid arteries, which are carried out between the branches of the ethmoid and wing-palatine arteries, as well as between a. angularis (from a. facialis, branches of a. carotis externa) and a. dorsalis nasi (from a. ophtalmica, branches of a. carotis interna).

Thus, the blood supply to the nose and paranasal sinuses has much in common with the blood supply to the orbits and the anterior cranial fossa.

Veins. The venous network of the nose and paranasal sinuses is also closely related to the anatomical structures mentioned above. The veins of the nasal cavity and paranasal sinuses repeat the course of the arteries of the same name, and also form a large number of plexuses connecting the veins of the nose with the veins of the eye socket, skull, face and pharynx (Fig. 2.1.11).

Venous blood from the nose and paranasal sinuses goes along the three main highways: posteriorly through v. sphenopalatina, ventrally through v. facialis anterior and cranial via vv. ethmoidales anterior et posterior.

Clinically, the connection of the anterior and posterior ethmoid veins with the veins of the orbit, through which connections are made with the dura mater and the cavernous sinus, is of great importance. One of the branches of the anterior ethmoid vein, penetrating through the ethmoid plate into the anterior cranial fossa, connects the nasal cavity and the orbit with the venous plexuses of the pia mater. The veins of the frontal sinus are connected with the veins of the dura mater directly and through the veins of the orbit. The veins of the sphenoid and maxillary sinuses are connected with the veins of the pterygoid plexus, the blood from which flows into the cavernous sinus and veins of the dura mater.

The lymphatic system of the nose and paranasal sinuses consists of the superficial and deep layers, while both halves of the nose have a close lymphatic connection with each other. The direction of the discharge lymphatic vessels of the nasal mucosa corresponds to the course of the main trunks and branches of the arteries that feed the mucous membrane.

Of great clinical importance is the established relationship between the lymphatic network of the nose and the lymph spaces in the membranes of the brain. The latter is carried out by lymphatic vessels perforating the ethmoid plate, and perineural lymphatic spaces of the olfactory nerve.

Innervation. Sensitive innervation of the nose and its cavity is carried out by the I and II branches of the trigeminal nerve (Fig. 2.1.12). The first branch is the orbital nerve - n. ophtalmicus - first passes through the thickness of the outer wall of sinus cavernosus, and then enters the orbit through fissura orbitalis superior. In the region of sinus cavernosus, sympathetic fibers from plexus cavernosus join the trunk of the orbital nerve (which explains sympathalgia in the pathology of the nasal ciliary nerve). Sympathetic branches to the oculomotor nerves depart from plexus cavernosus, and the nerve of the cerebellum is n. tentori cerebelli, which goes back and branches in the thickness of the cerebellar tent.

From n. ophtalmicus occurs nasal ciliary nerve, n. nasociliaris, giving rise to the anterior and posterior ethmoid nerves. The anterior ethmoid nerve - n. ethmoidalis anterior - из глазницы проникает в полость черепа через foramen ethmoidalis anterius, где идет под твердой мозговой оболочкой по верхней поверхности lamina cribrosa, а затем через отверстие в переднем отделе lamina cribrosa он проникает в полость носа, иннервируя слизистую оболочку лобной пазухи, передних клеток решетчатого лабиринта, боковую стенку носа, передние отделы перегородки носа и кожу наружного носа. Задний решетчатый нерв - n. ethmoidalis posterior аналогично переднему нерву также проникает из глазницы в полость черепа а затем через lamina cribrosa в нос, иннервируя слизистую оболочку клиновидной пазухи и задних клеток решетчатого лабиринта.

Вторая ветвь тройничного нерва - верхнечелюстной нерв, n. maxillaris, по выходу из полости черепа через foramen rotundum вступает в fossa pterygopalatina и далее через fissura orbitalis inferior в глазницу. Он анастомозирует с ganglion pterygopalatinum от которого отходят нервы, иннервирующие боковую стенку полости носа, перегородку носа, решетчатый лабиринт, верхнечелюстную пазуху.

Секреторная и сосудистая иннервация носа обеспечивается постганглионарными волокнами шейного симпатического нерва, идущими в составе тройничного нерва, а также парасимпатическими волокнами, которые в составе Видиева нерва проходят до ganglion pterygopalatinum и от этого узла их постганглионарные ветви проходят в полость носа.

Как уже отмечалось выше, при рассмотрении строения эпителия обонятельной области, от нижнего полюса обонятельных клеток, представляющих собой т.н. первичночувствующие клетки, отходят центральные аксоноподобные отростки. Эти отростки соединяются в виде обонятельных нитей, filae olphactoriae, которые проходят через решетчатую пластинку в обонятельные луковицы, bulbus olfactorius, будучи окруженными, как влагалищами, отростками мозговых оболочек. Здесь заканчивается первый нейрон. Мякотные волокна митральных клеток обонятельной луковицы образуют обонятельный тракт, tractus olfactorius, (II нейрон). Далее аксоны этого нейрона доходят до клеток trigonum olfactorium, substantia perforata anterior и lobus piriformis (подкорковые образования), аксоны которых (III нейрон), проходя в составе ножек мозолистого тела, corpus callosum, и прозрачной перегородки, достигают пирамидальных клеток коры girus hippocampi и аммониева рога, являющихся корковым представительством обонятельного анализатора (рис. 2.1.13)
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Анатомия околоносовых пазух

  1. Clinical anatomy of the paranasal sinuses
    The paranasal sinuses are located around the nasal cavity and communicate with it (Fig. 1.8). Only four pairs of airways: sinuses, maxillary labyrinth cells, frontal and sphenoid. There are anterior (maxillary, frontal, anterior and middle cells of the ethmoid bone) and posterior (sphenoid and posterior cells of the ethmoid bone) sinuses. Such a unit is convenient because pathology
  2. Анатомо-топографические особенности околоносовых пазух
    Имеются четыре пары воздухоносных околоносовых пазух: верхнечелюстные, клетки решетчатого лабиринта, лобные и клиновидные. There are anterior (maxillary, frontal, anterior and middle cells of the ethmoid bone) and posterior (sphenoid and posterior cells of the ethmoid bone) sinuses. Сообщение с полостью носа передних пазух происходит через средний носовой ход, а задних через верхний. Заболевания задних
    В полости носа и околоносовых пазухах, как и в других ЛОР органах, встречаются доброкачественные и злокачественные новообразования, весьма многообразные по морфологическому строению и клиническому проявлению. Отчетливой границы мелщу многими доброкачественными и злокачественными опухолями часто провести нельзя. Современные классификации опухолей, в том числе носа и околоносовых пазух, громоздки и
  6. Заболевания околоносовых пазух
    Воспалительные заболевания околоносовых пазух составляют25—30 % стационарной патологии ЛOP-органов. Наиболеечасто воспаление возникает в верхнечелюстной (гайморовой) пазухе (гайморит). Это обусловлено тем, что эвакуация содержимого из пазухи затруднена в связи с расположением соустья с полостью носа в верхней трети ее медиальной стенки, а также тем, что воспаление корней четырех задних
    Воспалительные заболевания околоносовых пазух (синуиты) относятся к числу наиболее частых заболеваний верхних дыхательных путей. По литературным данным, больные синуитами составляют около 1/3 общего числа госпитализированных в ЛОР стационары (Козлов М.Я., 1985; Солдатов И.Б.,1990; Пискунов Г.З. с соавт., 1992; Арефьева Н.А.,1994). Очаги воспаления в околоносовых пазухах могут являться источником
  8. Травмы околоносовых пазух
    У взрослых и детей наиболее часто повреждаются лобные пазухи, затем верхнечелюстные, решетчатый лабиринт и очень редко клиновидная пазуха. Обычно травма той или иной пазухи сочетается с повреждением других отделов лицевого скелета, полости черепа, глаз. Механическое или огнестрельное ранение лобной пазухи часто сопровождается повреждением передней доли мозга, решетчатого лабиринта, ситовидной
  9. Строение околоносовых пазух
    Околоносовые пазухи располагаются вокруг полости носа и сообщаются с ней (рис. 3). Only four pairs of airways: sinuses, maxillary labyrinth cells, frontal and sphenoid. There are anterior (maxillary, frontal, anterior and middle cells of the ethmoid bone) and posterior (sphenoid and posterior cells of the ethmoid bone) sinuses. Such a unit is convenient because pathology
    Околоносовые пазухи - это дополнительные расширения носовой полости. Они не вносят какого-либо прямого вклада в обоняние или дыхание — две функции, возложенные на носовую полость. Общая форма черепа в большой степени определяется вытянутыми и углубленными челюстями и связанными с ними мышцами. Это означает, что требуется «опора» для поддержки удлиненных челюстей, и участки кости между опорами и
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