The maxillary sinus is communicated. Maxillary Sinus: Anatomy
Paranasal sinuses. Topography of the paranasal sinuses. Maxillary sinus. Maxillary sinus. Topography of the maxillary (maxillary) sinus.
On each side, adjacent to the nasal cavity topjaw and frontal sinuses, ethmoid labyrinth and partly the sphenoid sinus.
Maxillary, or haimorova , sinus, sinus maxillaris, located in the thickness of the maxillary bone.
It is the largest of all the paranasal sinuses; its capacity for an adult is on average 10-12 cm3. The shape of the maxillary sinus resembles a tetrahedral pyramid, the base of which is located on the side wall of the nasal cavity, and the apex is at the zygomatic process. upper jaw... The front wall is facing anteriorly, the superior, or orbital, wall separates the maxillary sinus from the orbit, the posterior one faces the infratemporal and pterygo-palatine fossa. The lower wall of the maxillary sinus is formed by the alveolar process of the upper jaw, which separates the sinus from the oral cavity.
Internal, or nasal, wall of the maxillary sinus most important from a clinical point of view; it corresponds to most of the lower and middle nasal passages. This wall, with the exception of its lower part, is rather thin, and gradually becomes thinner from bottom to top. The opening through which the maxillary sinus communicates with the nasal cavity, hiatus maxillaris, is located high under the very bottom of the orbit, which contributes to the stagnation of the inflammatory secretion in the sinus. The nasolacrimal canal is adjacent to the front of the inner wall of the sinus maxillaris, and ethmoid cells are attached to the posterior upper part.
The superior, or orbital, wall of the maxillary sinus the thinnest, especially in the posterior region. With inflammation of the maxillary sinus (sinusitis), the process can spread to the orbit. In the thickness of the orbital wall passes the canal of the infraorbital nerve, sometimes the nerve and blood vessels directly adjacent to the sinus mucosa.
The front, or front, wall of the maxillary sinus formed by the area of \u200b\u200bthe upper jaw between the infraorbital edge and the alveolar process. It is the thickest of all the walls of the maxillary sinus; it is covered with soft tissues of the cheek and is easy to touch. A flat depression in the center of the anterior surface of the facial wall, called the "canine fossa", corresponds to the thinnest part of this wall. At the upper edge of the "canine fossa" there is an opening for the exit of the infraorbital nerve, foramen infraorbitale. Rr passes through the wall. alveolares superiores anteriores et medius (branches of the item infraorbitalis from the II branch trigeminal nerve) forming the plexus dentalis superior, as well as aa. alveolares superiores anteriores from the infraorbital artery (from a. maxillaris).
The lower wall, or the bottom of the maxillary sinus, is located near the posterior part of the alveolar process of the upper jaw and usually corresponds to the holes of the four posterior upper teeth... This makes it possible, if necessary, to open the maxillary sinus through the corresponding tooth socket. With an average size of the maxillary sinus, its bottom is approximately at the level of the bottom of the nasal cavity, but it is often located even lower.
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- the largest of the paranasal sinuses (see Fig. 1). The shape of the sinus mainly corresponds to the shape of the body of the upper jaw. The volume of the sinus has age and individual differences. The sinus can extend into the alveolar, zygomatic, frontal, and palatine processes. In the sinus, the upper, medial, anterolateral, posterolateral and lower walls are distinguished. It appears earlier than other sinuses and in newborns it is in the form of a small fossa. The sinus gradually increases by the period of puberty, and in old age it becomes even larger due to resorption of bone tissue.
The upper wall of the sinus, separating it from the orbit, over a greater extent consists of a compact substance and has a thickness of 0.7-1.2 mm, thickening at the infraorbital edge and zygomatic process. The lower wall of the infraorbital canal and infraorbital sulcus is very thin. Sometimes, in some areas of the bone, it is completely absent, and the nerve and vessels passing in this canal are separated from the mucous membrane of the maxillary sinus only by the periosteum.
Medial wall, bordering the nasal cavity, consists entirely of a compact substance. Its thickness is smallest in the middle of the lower edge (1.7-2.2 mm), the largest - in the antero-inferior angle (3 mm). At the place of transition to the posterolateral wall, the medial wall is thin, when passing to the anterior wall it thickens and there is an alveolus of the canine in it. In the upper-posterior section of this wall there is an opening - a maxillary cleft connecting the sinus with the middle nasal passage.
Anterolateral wall somewhat depressed in the area of \u200b\u200bthe canine fossa. In this place, it entirely consists of a compact substance and has the smallest thickness (0.2-0.25 mm). With distance from the fossa, the wall thickens (4.8-6.4 mm). At the alveolar, zygomatic, frontal processes and the inferolateral edge of the orbit, the compact plates of this wall are divided by spongy substance into outer and inner. The anterolateral wall contains several anterior alveolar tubules that run from the infraorbital canal to the roots of the anterior teeth and serve for the passage of blood vessels and nerves to the anterior teeth.
Figure: 1. Maxillary sinus; frontal cut of the skull, back view:
1 - groove of the superior sagittal sinus; 2 - cock's comb; 3 - lattice plate; 4 - frontal sinus; 5 - lattice maze; 6 - eye socket; 7 - maxillary sinus; 8 - opener; 9 - incisor hole; 10 - palatine process; 11 - bottom turbinate; 12 - middle turbinate; 13 - upper nasal concha; 14 - perpendicular plate of the ethmoid bone
Posterolateral wall over a greater extent, it is a compact plate, expanding at the transition to the zygomatic and alveolar processes and containing a spongy substance in these places. The thickness of the wall is the smallest in the upper-posterior area (0.8-1.3 mm), the largest - near the alveolar process at the level of the 2nd molar (3.8-4.7 mm). In the thicker back lateral wall the posterior alveolar tubules pass, from which branches branch off, connecting with the anterior and middle alveolar tubules. With strong pneumatization of the upper jaw, as well as as a result of pathological changes, the inner wall of the tubules becomes thinner and the mucous membrane of the maxillary sinus is adjacent to the alveolar nerves and blood vessels.
The lower wall has the shape of a groove where the anterolateral, medial and posterolateral sinus walls converge. The bottom of the groove in some cases is even, in others it has protrusions corresponding to the alveoli of the 4 front teeth. The protrusion of the alveoli of the teeth is most pronounced on the jaws, in which the floor of the sinus is at the level of the nasal cavity or below it. The thickness of the compact plate separating the bottom of the alveoli of the 2nd molar from the bottom of the maxillary sinus often does not exceed 0.3 mm.
Ossification: in the middle of the 2nd month of intrauterine development in connective tissue of the maxillary and medial nasal processes, several points of ossification appear, which merge by the end of the 3rd month, forming the body, nasal and palatine processes of the upper jaw. The incisor bone has an independent ossification point. At the 5-6th month of the prenatal period, the maxillary sinus begins to develop.
Human Anatomy S.S. Mikhailov, A.V. Chukbar, A.G. Tsybulkin
46. Clinical Anatomy paranasal sinuses.
The paranasal sinuses (sinus paranasalis) include the air cavities that surround the nasal cavity and communicate with it through the holes.
There are four pairs of sinuses: maxillary; frontal; ethmoid sinuses; wedge-shaped.
In clinical practice, the paranasal sinuses are divided into anterior (maxillary, frontal, anterior and middle ethmoid sinuses) and posterior (sphenoid and posterior ethmoid sinuses). Such a subdivision is convenient in that the pathology of the anterior sinuses is somewhat different from that of the posterior sinuses. In particular, communication with the nasal cavity of the anterior sinuses is carried out through the middle, and the posterior ones through the upper nasal passage, which is important in the diagnostic plan. Diseases of the posterior sinuses (especially wedge-shaped) are much less common than the anterior ones.
Maxillary sinuses (sinus maxillaris) - paired, located in the body of the upper jaw, the largest, the volume of each of them is on average 10.5-17.7 cm 3. The inner surface of the sinuses is covered with a mucous membrane with a thickness of about 0.1 mm, the latter is represented by a multi-row cylindrical ciliated epithelium. The ciliated epithelium functions in such a way that the movement of mucus is directed upward in a circle to the medial corner of the sinus, where the anastomosis with the middle nasal passage of the nasal cavity is located. In the maxillary sinus, anterior, posterior, superior, inferior and medial walls are distinguished.
Medial (nasal) wall the sinus from a clinical point of view is the most important. It corresponds to most of the lower and middle nasal passages. Submitted by bone plate, which, gradually thinning, in the area of \u200b\u200bthe middle nasal passage can turn into a duplicate of the mucous membrane. In the anterior part of the middle nasal passage, in the lunate fissure, a duplicate of the mucous membrane forms a funnel (infundibulum), at the bottom of which there is an opening (ostium maxillare) connecting the sinus with the nasal cavity.
IN upper section the medial wall of the maxillary sinus is located the excretory anastomosis - ostium maxillare, in connection with which the outflow from it is difficult. Sometimes, when viewed with endoscopes in the posterior parts of the lunate fissure, an additional excretory opening of the maxillary sinus (foramen accesorius) is found, through which the polyposis changed mucous membrane from the sinus can protrude into the nasopharynx, forming a choanal polyp.
Front, or front, wall extends from the lower edge of the orbit to the alveolar process of the upper jaw and is most dense in the maxillary sinus, is covered with soft tissues of the cheek and is palpable. A flat bony depression on the anterior surface of the facial wall is called the canine or canine fossa (fossa canina), which is the thinnest part of the anterior wall. Its depth can vary, but the average is 4-7 mm. With a pronounced canine fossa, the anterior and upper walls of the maxillary sinus are in the immediate vicinity of the medial. This must be taken into account when performing a sinus puncture, because in such cases the puncture needle can penetrate soft tissue cheeks or into the orbit, which sometimes leads to purulent complications. At the upper edge of the canine fossa is the infraorbital foramen, through which the infraorbital nerve (n. Infraorbitalis) exits.
The superior, or orbital wall, is the thinnest, especially in the posterior region, where digiscences often occur. In its thickness, the infraorbital nerve canal passes, sometimes there is a direct attachment of the nerve and blood vessels to the mucous membrane lining the upper wall of the maxillary sinus. This should be taken into account when scraping the mucous membrane during surgery. The posterior superior (medial) sections of the sinus directly border on the group of posterior cells of the ethmoid labyrinth and the sphenoid sinus, and therefore the surgical approach to them is also convenient through the maxillary sinus. The presence of the venous plexus associated with the orbit by the solid cavernous sinus meninges, can contribute to the transition of the process to these areas and the development of formidable complications, such as thrombosis of the cavernous (cavernous) sinus, phlegmon of the orbit.
Back wall the sinuses are thick, corresponds to the tuberus of the upper jaw (tuber maxillae) and with its posterior surface faces the pterygopalatine fossa, where the maxillary nerve, pterygopalatine node, maxillary artery, and pterygopalatine venous plexus are located.
The bottom wall, or the bottom of the sinus, is the alveolar process of the upper jaw. The bottom of the maxillary sinus, with its medium size, lies approximately at the level of the bottom of the nasal cavity, but is often located below the latter. With an increase in the volume of the maxillary sinus and lowering its bottom towards the alveolar process, there is often a standing in the sinus of the roots of the teeth, which is determined radiographically or during surgery on the maxillary sinus. This anatomical feature increases the possibility of developing odontogenic sinusitis. Sometimes on the walls of the maxillary sinus there are bony ridges and bridges that divide the sinus into bays and very rarely into separate cavities. Both sinuses are often of different sizes.
Ethmoid sinuses (sinus ethmoidalis) - consist of separate communicating cells, separated by thin bone plates. The number, volume and location of lattice cells are subject to significant variations, but on average there are 8-10 of them on each side. The ethmoid labyrinth is a single ethmoid bone that is bordered by the frontal (top), sphenoid (back), and maxillary (lateral) sinuses. The cells of the lattice labyrinth laterally adjoin the paper plate of the orbit. A common variant of the arrangement of lattice cells is their spread into the orbit in the anterior or posterior regions. In this case, they border on the anterior cranial fossa, while the ethmoid plate (lamina cribrosa) lies below the vault of the ethmoid labyrinth cells. Therefore, when opening them, you must strictly adhere to the lateral direction, so as not to penetrate into the cranial cavity through the ethmoid plate (lam.cribrosa). The medial wall of the ethmoid labyrinth is simultaneously the lateral wall of the nasal cavity above the inferior turbinate.
Depending on the location, the front, middle and back cells of the trellised labyrinth are distinguished, with the front and middle cells opening into the middle nasal passage, and the rear ones opening into the upper one. The optic nerve runs close to the ethmoid sinuses.
Anatomical and topographic features of the ethmoid labyrinth can contribute to the transition of pathological processes into the orbit, the cranial cavity, and the optic nerve.
Frontal sinuses (sinus frontalis) - paired, located in the scales of the frontal bone. Their configuration and sizes are variable, the average volume of each is 4.7 cm 3, on the sagittal section of the skull, its triangular shape can be noted. The sinus has 4 walls. The lower (orbital), for the most part, is the upper wall of the orbit and for a short distance it borders on the cells of the ethmoid labyrinth and the nasal cavity. The front (front) wall is the thickest (up to 5-8 mm). The posterior (cerebral) wall is bordered by the anterior cranial fossa, it is thin, but very strong, and consists of compact bone. The medial wall (septum of the frontal sinuses) in the lower section is usually located in the midline, and upward can deviate to the sides. The anterior and posterior walls in the upper section converge at an acute angle. On the lower wall of the sinus, anterior to the septum, there is an opening of the frontal sinus canal, through which the sinus communicates with the nasal cavity. The channel can be about 10-15 mm long and 1-4 mm wide. It ends in the anterior part of the lunar slit in the middle nasal passage. Sometimes the sinuses spread laterally, they can have bays and partitions, be large (more than 10 cm 3), in some cases they are absent, which is important to keep in mind in clinical diagnosis.
Sphenoid sinuses(sinus sphenoidalis) - paired, located in the body of the sphenoid bone. The size of the sinuses is very variable (3-4 cm 3). Each sinus has 4 walls. The sinus septum divides the sinuses into two separate cavities, each of which has its own outlet leading to the common nasal passage (sphenoethmoidal pocket). This arrangement of the sinus fistula promotes the outflow of discharge from it into the nasopharynx. The lower wall of the sinus is partly the fornix of the nasopharynx, and partly the roof of the nasal cavity. This wall usually consists of spongy tissue and is of considerable thickness. The upper wall is represented by the lower surface of the sella turcica, the pituitary gland and part of the frontal lobe of the brain with the olfactory convolutions are adjacent to this wall. The posterior wall is the thickest and passes into the basilar part of the occipital bone. The lateral wall is most often thin (1-2 mm), with which the internal carotid artery and the cavernous sinus border, the oculomotor, the first branch of the trigeminal, trochlear and abducens nerves pass here.
Blood supply. The paranasal sinuses, like the nasal cavity, are supplied with blood from the maxillary (branch of the external carotid artery) and ocular (branch of the internal carotid) arteries. The maxillary artery provides nutrition mainly to the maxillary sinus. The frontal sinus is supplied with blood from the maxillary and ophthalmic arteries, the wedge-shaped - from the pterygo-palatine artery and from the branches of the meningeal arteries. The ethmoid labyrinth cells are fed from the ethmoid and lacrimal arteries.
Venous system sinuses are characterized by the presence of a wide-looped network, especially developed in the area of \u200b\u200bnatural anastomoses. The outflow of venous blood occurs through the veins of the nasal cavity, but the branches of the veins of the sinuses have anastomoses with the veins of the orbit and the cranial cavity.
Lymphatic drainage from the paranasal sinuses is carried out mainly through the lymphatic system of the nasal cavity and directed to the submandibular and deep cervical lymph nodes.
The innervation of the paranasal sinuses is carried out by the first and second branches trigeminal nerve and from the pterygopalatine node. From the first branch - the orbital nerve - (n. Ophtalmicus) originate the anterior and posterior ethmoid arteries - n. ethmoidales anterior posterior, innervating the upper floors of the nasal cavity and paranasal sinuses. From the second branch (n. Maxillaris) branches n. sphenopalatine and n. infraorbitalis, innervating the middle and lower floors of the nasal cavity and paranasal sinuses.
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The maxillary sinus is located in the human skull in the upper jaw (on both sides of the nose). From an anatomical point of view, it is considered the largest nasal appendage in volume. The average volume of the maxillary sinus of an adult can be 10-13 cm³.
Anatomy of the maxillary sinuses
The size and shape of the maxillary sinuses tend to vary depending on the age of the person. Most often, their shape can resemble something like a four-sided pyramid of irregular shape. The boundaries of these pyramids are defined by four walls:
- upper (eye);
- front (front);
- back;
- internal.
At its base, the pyramid has a so-called bottom (or bottom wall). There are often cases when its outlines have an asymmetrical shape. Their volume depends on the thickness of the walls of these cavities. If the maxillary sinus has thick walls, then its volume will be much less. In the case of thin walls, accordingly, the volume will be larger.
Under normal conditions of formation, the maxillary sinuses are in communication with the nasal cavity. This, in turn, is of no small importance for the formation of the sense of smell. A special area of \u200b\u200bthe maxillary sinuses takes part in determining the smell, performs the respiratory functions of the nose and even has a resonating effect at the stages of the formation of a person's voice. Due to the cavities located near the nose, a sound and timbre unique for each person are formed.
The inner wall of the maxillary sinuses, which is closest to the nose, has an opening connecting the sinus and the middle nasal passage. Each person has four pairs of sinuses: ethmoid, frontal, maxillary, and wedge-shaped.
The bottom of the maxillary cavities is formed by the alveolar ridge, which separates it from the oral cavity. The lower wall of the sinuses is located in the immediate vicinity of the molars. This often causes the teeth to reach the bottom of the sinuses with their roots and become covered with mucous membranes. It is based on a small number of vessels, goblet-shaped cells and nerve endings. This leads to the fact that inflammation and sinusitis can exist for a long period without serious symptoms.
The walls of the maxillary cavities
The eye (upper) wall is thinner than the other walls. The thinnest section of this wall is in the rear compartment.
In the case of sinusitis (an inflammatory process accompanied by the filling of the maxillary cavities with mucus and pus), the affected areas will be in direct proximity to the orbit area, which is very dangerous. This is due to the fact that in the very wall of the orbits there is a canal with the infraorbital nerve. Very often there are cases when this nerve and important vessels are located at a close distance from the mucous membranes of the maxillary sinuses.
The nasal (inner) wall is of particular importance (based on many clinical research). This is due to the position that it has in line with the main part of the middle and lower nasal passages. Its peculiarity lies in the fact that it is quite thin. The exception is bottom part walls. In this case, a gradual thinning occurs from the bottom up the wall. Near the very bottom of the orbit is an opening through which the nasal cavity communicates with the maxillary sinuses. This often leads to the fact that the inflammatory secret in them stagnates. In the region of the posterior part of the nasal wall, there are lattice-shaped cells, and the place of the nasolacrimal canal is located near the anterior parts of the nasal wall.
The region of the bottom in these cavities is located close to the alveolar process. The lower wall of the maxillary sinuses is often located above the holes of the last four teeth of the upper row. In case of urgent need, the maxillary sinus is opened by means of the corresponding tooth socket. Very often the bottom of the sinuses is located at the same level as the bottom of the nasal cavity, but this is with the usual volume of the maxillary sinuses. In other cases, it is located just below.
The formation of the front (front) wall of the maxillary sinuses occurs in the region of the alveolar ridge and the infraorbital margin. The upper jaw plays an important role in this process. In comparison with other walls of the maxillary sinuses, the front wall is considered to be thicker.
It is covered with soft tissues of the cheeks, it can even be felt. The so-called canine pit, which is called the flat pits located in the central part of the front wall, is the thinnest part. At the upper edge of this site is the outlet for the optic nerves. The trigeminal nerve passes through the facial wall of the maxillary sinus.
The ratio of maxillary sinuses and teeth
Very often there are cases when there is a need surgical intervention in the area of \u200b\u200bthe upper teeth, which is influenced by the anatomical characteristics of the maxillary sinuses. This also applies to implants.
There are three types of ratios between the lower wall of the maxillary sinuses and the upper row of teeth:
- the bottom of the nasal cavity is lower than bottom wall maxillary cavities;
- the bottom of the nasal cavity is located at the same level with the bottom of the maxillary sinuses;
- the nasal cavity with its bottom is located above the lower walls of the maxillary sinuses, which makes it possible for the dental roots to have a free fit to the cavities.
When a tooth is removed in the area of \u200b\u200bthe maxillary sinus, the process of atrophy begins. The bilateral nature of this process results in a rapid quantitative and qualitative deterioration of the maxillary bones, as a result of which further dental implantation can be considered very difficult.
Inflammation of the maxillary cavities
When inflammatory process (most often, inflammatory lesions affect more than one cavity) the disease is diagnosed by doctors as sinusitis. The symptoms of the disease are as follows:
- pain in the area of \u200b\u200bthe cavities;
- respiratory and olfactory nasal dysfunction;
- prolonged runny nose;
- heat;
- irritable reaction to light and noise;
- tearing.
In some cases, there is swelling of the cheek of the affected side. A dull pain may be present during the feeling of the cheek. Sometimes the pain can cover the entire part of the face on the side of the inflamed sinuses.
In order to more correctly diagnose the disease and prescribe the appropriate treatment, it is required to make an X-ray of the maxillary cavities affected by inflammation. The ENT doctor is engaged in the treatment of this disease. To prevent the appearance of sinusitis, it is necessary to carry out certain preventive measures in order to increase immunity.
Prevention and treatment of inflammatory processes
There are several simple ways sinusitis treatment:
- warming up;
- washing;
- compress.
When the maxillary sinuses are inflamed, they fill with inflammatory mucus and pus. In this regard, the most important stage on the way to recovery is the procedure for cleaning the maxillary cavities from purulent accumulation.
The cleansing process itself can be organized at home. In this case, you first need to plunge your head into extremely hot water for 3-5 minutes, then dip your head in cold water... After 3-5 such manipulations, you should take a horizontal position, lying on your back, with your head thrown back so that the nostrils are vertical. Due to the sharp temperature contrast, the areas affected by inflammation are most easily cleaned.
Do not take your health lightly, even if you have a slight runny nose.
The disease of sinusitis or sinusitis is a serious threat for the general well-being of a person, and in some cases - life, especially if the disease acquires chronic symptoms.
Sinusitis of the maxillary cavities often contributes to the appearance of diseases such as bronchial asthma, chronic bronchitis or pneumonia. Due to the fact that anatomically the maxillary cavities border on the brain and the orbits, this disease has a high share of the risk of giving serious complications in the form of inflammation of the meninges, and in some cases, cerebral abscess.
The nasal cavity has paranasal sinuses, which communicate with various nasal passages (Fig. 50). So, in the upper nasal passage, the body cavity of the main bone and the posterior cells of the ethmoid bone open, in the middle nasal passage - the frontal and maxillary sinuses, the anterior and middle cells of the ethmoid bone. The lacrimal canal flows into the lower nasal passage.
Figure: fifty.
A - the outer wall of the nasal cavity with holes in the paranasal sinuses: 1 - frontal sinus; 3 - opening of the frontal sinus; 3 - opening of the anterior ethmoid cells; 4 - opening of the maxillary sinus; 5 - holes of the posterior cells of the ethmoid bone; 6 - the main sinus and its opening; 7 - pharyngeal opening auditory tube; 8 - opening of the nasolacrimal duct. B - nasal septum: 1 - crista galli; 2 - lamina cribrosa; 3 - lamina perpendicularis ossis ethmoidalis; 4 - opener; 5 - hard palate; 5 - cartilago septi nasi.
Maxillary sinus (sinus maxillaris Highmori) is located in the body of the upper jaw. It begins to be created from the 10th week of embryonic life and develops up to 12-13 years. In an adult, the volume of the cavity ranges from 4.2-30 cm 3, it depends on the thickness of its walls and less on its position. The shape of the sinus is irregular, it has four main walls. The anterior (in 1/3 of cases) or antero-external (in 2/3 of cases) wall is represented by a thin plate corresponding to the fossa canina. There is n on this wall. infraorbitalis together with the blood vessels of the same name.
The upper wall of the sinus is also the lower wall of the orbit. In the thickness of the wall there is canalis infraorbitalis, containing the mentioned neurovascular bundle. At the site of the latter, the bone may be thinned or have a gap. In the presence of a gap, the nerve and blood vessels are separated from the sinus only by the mucous membrane, which leads to inflammation of the inferior orbital nerve with sinusitis. Usually, the top wall of the sinus is flush with the top of the middle nasal passage. N.N. Rezanov points to a rare option when this wall of the sinus is low and the middle nasal passage is adjacent to the inner surface of the orbit. This is due to the possibility of penetration into the orbit of the needle during the puncture of the maxillary sinus through the nasal cavity. Often, the dome of the sinus extends into the thickness of the inner wall of the orbit, pushes the ethmoid sinuses up and back.
The lower wall of the maxillary sinus is represented by the alveolar process of the jaw, corresponding to the roots of the 2nd small and anterior large molars. The zone of the position of the roots of the teeth can protrude into the cavity in the form of an elevation. The bone plate separating the cavity from the root is often thinned, sometimes has a gap. These conditions favor the spread of infection from the affected roots of the teeth to the maxillary sinus, explain the cases of penetration of the tooth into the sinus at the time of its extirpation. The bottom of the sinus may be 1–2 mm above the bottom of the nasal cavity, at the level of this bottom or below it as a result of the development of the alveolar bay. The maxillary cavity rarely extends under the bottom of the nasal cavity, forming a small depression (buchta palatina) (Fig. 51).
Figure: 51. Paranasal sinuses nose, maxillary sinus.
A - sagittal cut: B - frontal cut; В - construction options - high and low position of the lower wall: 1 - canalis infraorbitalis; 2 - fissura orbitalis Inferior; 3 - fossa pterygopalatina; 4 - maxillary sinus; 5- ethmoid cells; 6 - eye socket; 7 - processus alveolaris; 8 - lower nasal concha; 9 - nasal cavity; 10 - buchta prelacrimalis; 11 - canalis infraorbitalis (deprived of the lower wall); 12 - buchta palatina; 13 - buchta alveolaris; G - frontal sinus on a sagittal cut; D - options for the structure of the frontal sinus.
The inner wall of the maxillary sinus is adjacent to the middle and lower nasal passages. The wall of the lower nasal passage is solid, but thin. Here it is relatively easy to puncture the maxillary sinus. The wall of the middle nasal passage has a webbed structure and an opening communicating the sinus with the nasal cavity over a considerable extent. Hole length 3-19 mm, width 3-6 mm.
The posterior wall of the maxillary sinus is represented by the maxillary tubercle in contact with the pterygopalatine fossa, where n. infraorbitalis, ganglion sphenopalatinum, a. maxillaris with its branches. Through this wall you can approach the pterygopalatine fossa.
Frontal sinuses (sinus frontalis) are located in the thickness of the frontal bone, corresponding to the superciliary arches. They look like triangular pyramids with a downward base. Sinuses develop from 5-6 to 18-20 years. In adults, their volume reaches 8 cm 3. Upward, the sinus extends somewhat beyond the superciliary arches, outward - to the outer third of the upper edge of the orbit or to the supraorbital notch and descends down into the nasal part of the bone. The anterior wall of the sinus is represented by the superciliary tubercle, the posterior wall is relatively thin and separates the sinus from the anterior cranial fossa, the lower wall forms part of the upper wall of the orbit and at the midline of the body - part of the nasal cavity, the inner wall is the septum separating the right and left sinuses. The top and side walls are absent, since its front and back walls converge at an acute angle. The cavity is absent in about 7% of cases. The partition separating the cavities from each other does not occupy the middle position in 51.2% (M.V. Miloslavsky). The cavity opens through the canal (canalis nasofrontalis) up to 5 mm in length into the middle nasal passage, in front of the opening of the maxillary sinus. In the frontal sinus, canalis nasofrontalis is formed at the bottom of its funnel. This promotes the drainage of mucus from the sinus. Tillo points out that the frontal sinus can sometimes open into the maxillary sinus.
Ethmoid sinuses (sinus ethmoidalis) are represented by cells corresponding to the level of the upper and middle turbinates, make up upper part lateral wall of the nasal cavity. These cells communicate with each other. On the outside, the cavities are delimited from the orbit by a very thin bone plate (lamina papyrocea). If this wall is damaged, air from the cells of the cavity can penetrate into the tissue of the periorbital space. The resulting emphysema produces a protrusion eyeball - exophthalmos. Above, the cells of the sinus are delimited by a thin bony septum from the anterior cranial fossa. The anterior group of cells opens into the middle nasal passage, the posterior one - into the upper nasal passage.
Main sinus (sinus sphenoidalis) is located in the body of the main bone. It develops between the ages of 2 and 20. The sinus is divided into right and left by a septum along the midline. The sinus opens into the upper nasal passage. The hole lies 7 cm from the nostril along a line following through the middle of the middle turbinate. The position of the sinus made it possible to recommend that surgeons approach the pituitary gland through the nasal cavity and nasopharynx. The main sinus may or may not be present.
Lacrimal canal (canalis nasolacrimalis) is located in the zone of the lateral border of the nasal region (Fig. 52). It opens into the lower nasal passage. The canal opening is located under the anterior edge of the inferior turbinate on the outer wall of the nasal passage. It is 2.5-4 cm from the posterior edge of the nostril. The length of the lacrimal canal is 2.25-3.25 cm (N.I. Pirogov). The channel runs in the thickness of the outer wall of the nasal cavity. In the lower segment, it is limited bone tissue only from the outside, from other sides it is covered with the mucous membrane of the nasal cavity.
Figure: 52. Topography of the lacrimal passages.
1 - fornix sacci lacrimalis; 2 - ductus lacrimalis superior; 3 - papilla et punctum lacrimale superior; 5 - caruncula lacrimalis; 6 - ductus et ampula lacrimalis Inferior; 7 - saccus lacrimalis; 8 - m. orbicularis oculi; 9 - m. obliquus oculi inferior; 10 - sinus maxillaris; 11 - ductus nasolacrimalis.
A - cross section: 1 - lig. palpebrale medialis; 2 - pars lacrimalis m. orbicularis oculi; 3 - septum orbitale; 4 - f. lacrimalis; 5 - saccus lacrimalis; 6 - periosteum