18. Upper jaw, its parts, surfaces, openings, canals and their contents. Buttresses of the upper jaw and their meaning.

upper jaw (maxilla) - paired bone. The upper jaw has a body and four processes: frontal, alveolar, palatine and zygomatic (Fig. 54).

Body of the upper jaw(corpus maxillae) has an irregular shape, it is limited to four surfaces.

Anterior surface of the body(facies anterior) slightly concave. It is separated from the orbital surface by the infraorbital margin (mdrgo infraorbitalis), under which the infraorbital foramen (fordmen infraorbitale) is located. Vessels and nerves pass through this opening. On the medial edge of the anterior surface is a deep nasal notch (incisiira nasdlis). It is involved in the formation of the anterior opening of the nasal cavity ( pear-shaped aperture).

Orbital surface(fdcies orbitdlis) is involved in the formation of a slightly concave lower wall of the orbit. In its posterior sections, the anterior infraorbital sulcus (sulcus infraorbitals) begins, passing anteriorly into the canal of the same name, which opens with the infraorbital foramen.

Infratemporal surface(fades infratempordlis) is separated from the anterior surface by the base of the zygomatic process. On the infratemporal surface there is a tubercle of the upper jaw (tuber maxillae), on which alveolar canals (canales alveolares) open with small alveolar openings. Blood vessels and nerves pass through these channels. The greater palatine sulcus (sulcus palatinus major) is vertically located medial to the tubercle of the upper jaw.

nasal surface(fdcies nasalis) of the body of the upper jaw is involved in the formation of the lateral wall of the nasal cavity. It shows the maxillary cleft - a triangular opening that leads to the air-bearing maxillary (maxillary) sinus (sinus maxilldris), located in the thickness of the body of the maxillary bone. Anterior to the maxillary cleft is a vertical lacrimal sulcus (sulcus lacrimdlis). This groove is involved in the formation of the nasolacrimal canal, which is also limited by the lacrimal bone and the inferior nasal concha.

frontal process(processus frontalis) departs from the body of the upper jaw upward, where it connects to the nasal part of the frontal bone. On the lateral surface of the process there is a vertically located anterior lacrimal crest (crista lacrimdlis anterior). It limits the tear trough in front. On the medial surface of the process, a ethmoid ridge (crista ethmoidlis) is visible, with which the anterior part of the middle nasal concha of the ethmoid bone is connected.

Alveolar ridge(processus alveoldris) departs from the upper jaw down in the form of a roller - the alveolar arch (drcus alveol & ris). This arc contains recesses - dental alveoli (alveoli dentdles) for the roots of eight teeth of one half of the upper jaw. The alveoli are separated by thin bony interalveolar septa (septa interalveoldria). t

palatine process(processus palatinus) is a thin horizontal plate involved in the formation of the hard palate. The lower surface of this process in the posterior sections has several longitudinally oriented palatine furrows (sulci palatini). In the anterior part of the process, along the midline of the hard ije6a, the incisive canal (candlis incisivus) passes from bottom to top. Posteriorly, the palatine process is connected to the horizontal plate of the palatine bone.

zygomatic process(processus zygomaticus) departs from the upper lateral part of the body of the upper jaw towards the zygomatic bone.

Contortoresses:

Frontal-nasal buttress rests below on the alveolar elevations in the canine region, at the top it continues in the form of a reinforced plate of the frontal process of the upper jaw, reaching the nasal part of the frontal bone. The right and left buttresses in the area of ​​the fore part of the frontal bone are strengthened by transverse bone ridges in the form of superciliary arches. This buttress balances the force of upward pressure developed by the fangs.

Alveolar-zygomatic buttress goes from the alveolar eminence of the 1st and 2nd molars, goes up the zygomatic-alveolar crest to the zygomatic bone, which redistributes pressure: posteriorly - to the zygomatic process of the temporal bone, from above - to the zygomatic process of the frontal bone, medially - to the zygomatic process and infraorbital margin upper jaw, towards the fronto-nasal buttress. The alveolar-zygomatic buttress is most pronounced and balances the force developed by the chewing teeth in the direction from bottom to top, from front to back and from the outside inwards.

Pterygopalatine buttress starts from the alveolar elevation of the molars and the tubercle of the upper jaw, goes up, where it is enhanced by the pterygoid process of the sphenoid bone and the perpendicular plate of the palatine bone. This buttress balances the force developed by the molars from bottom to top and from back to front.

palatal buttress formed by the palatine processes of the upper jaw and the horizontal plates of the palatine bone, connecting the right and left alveolar arches in the transverse direction. This buttress balances the force developed during chewing in the transverse direction.

The upper jaw is a paired bone, which is located in the center of the front of the face and connects with the rest of its bones.

It performs a number of important functions: it participates in the work of the chewing apparatus, in the formation of cavities for the nose and mouth, and the partitions between them.

The anatomy of the human upper jaw has a complex structure. It consists of a body and 4 processes - alveolar, where the cells of the teeth are located, frontal (directed upwards), palatine and zygomatic.

The upper jaw is much thinner, it is also quite light due to the sinus (cavity), with a volume of about 4-6 cm3.

The body of the jaw consists of the anterior, infratemporal, nasal and orbital surfaces. The anterior includes an opening where thin blood vessels and nerve processes pass.

Blood supply occurs through 4 alveolar openings in the infratemporal zone.

The nasal surface forms the nasal concha, and the flat orbital contains the lacrimal notch.

The upper jaw is immobile due to fusion with the bones of the face, has almost no junction points of the masticatory muscles and is under the action of a pressure force, and not a traction force.

frontal process

(lat. processus frontalis)

The frontal process of the maxilla is directed upwards and connects with the nasal part of the frontal bone. It has a medial and lateral zone. The medial region of the frontal process includes the lacrimal crest. The back part borders on the lacrimal groove.

palatine process

(lat. processus palatinus)

The palatine process of the upper jaw is part of the system of hard tissues of the palate. It has a connection in the form of a median suture with a process of the opposite side, as well as bone plates. A nasal ridge forms along this suture. The palatine process has a smooth surface above and a rough surface below.

Alveolar ridge

(lat. processus alveolaris)

The alveolar process of the upper jaw consists of an outer (buccal), inner (lingual) wall, as well as dental alveoli from a spongy substance where the teeth are placed. The complex structure of the alveolar process also includes bony septa (interdental and interradicular).

Anterior surface of the body

(lat. fades anterior)

The anterior surface of the body borders on the infraorbital margin. It has a hole with a diameter of 2-6 mm, under it there is a canine pit. There begins the muscle that is responsible for raising the corner of the mouth. The anterior surface of the body is slightly curved.

infraorbital foramen

(lat. foramen infraorbitale)

The infraorbital foramen is located on the anterior surface of the body approximately at the level of the 5th or 6th tooth. The thinnest blood vessels pass through it, as well as the processes of the trigeminal nerve. The diameter of the infraorbital foramen is quite large (it can reach 6 mm).

zygomatic process

(lat. zygomaticus)

The zygomatic process of the maxilla starts from the upper outer corner of the body. It is directed laterally (refers to the lateral side of the surface), has a rough end. The zygomatic process of the frontal bone connects to the temporal process.

Posterior (infratemporal) surface of the body

(lat. facies infratemporalis)

The posterior surface of the body is separated from the anterior by the zygomatic process and has an uneven, often convex shape. Here is the tubercle of the upper jaw, where the alveolar canals open. A large palatine sulcus is also located on the side of the tubercle of the posterior surface of the body.

The two bone structures located near the mouth opening are the human jaw. This is one of the most complex parts of the body, because it is individual, and its structure determines facial features.

Functions

The shape of the jaws determines the oval of the face, external attractiveness. But this is not the only function of the body:

1. Chewing. On the jaws fixed teeth involved in the process of chewing and digestion. The bone is able to withstand a high chewing load.
2. Implementation swallowing movements.
3. Talk. Movable bones take part in articulation. If they are injured or incorrectly located, diction is disturbed.
4. Breath. The participation of the organ in breathing is indirect, but if it is damaged, it is impossible to inhale or exhale.
5. Fixation sense organs.

The jaw is one of the most complex parts of the body.

The organ is designed for a high load, its chewing force can reach 70 kilograms.

The structure of the lower jaw

The structure is formed by two fused branches. At birth, they form a whole, but later separate. The bone is uneven; it has many roughnesses, depressions, tubercles, necessary to ensure the fixation of muscles and ligaments.

The strength of the lower bones is less than the upper ones. This is necessary so that they bear the main blow during injuries, since the upper ones protect the brain.

The bones of the lower jaw are less durable than those of the upper jaw.

The frontal region is the location of the mental foramen, through which the blood supply is carried out, and the tubercle for the localization of the teeth. If you see a tooth in section, it will be found that it is attached to the alveolar opening; at the bottom there are 14-16 (in adults). Another component of the organ is the temporal part, associated with the joint, having ligaments and cartilage that provide movement.

upper jaw

The upper structure is a paired bone with a large cavity - the maxillary sinus. The bottom of the sinus is located next to some teeth - the second and first molars, the second.

The structure of the tooth suggests the presence of roots, which require processing during pulpitis. Proximity to the maxillary sinus complicates the procedure: it happens that due to a doctor's mistake, the bottom of the sinus is damaged.

The bone has processes:

• frontal (upwards);
• palatine (facing the center);
• alveolar;
• zygomatic.

The structure of the jaw is the same for all people, the shape, dimensions are individual parameters.

The alveolar process is the location of the teeth of the upper jaw. They are attached to the alveoli - small depressions. The largest recess is for the canine.

The organ has four surfaces:

• anterior with alveolar process;
• nasal;
• orbital, creating the basis for the orbit;
• infratemporal.

Upper jaw, maxilla , a steam room, is located in the center of the face and connects to all its bones, as well as to the ethmoid, frontal and sphenoid bones. The upper jaw takes part in the formation of the walls of the orbit, nasal and oral cavities, pterygopalatine and infratemporal fossae. It distinguishes the body and four processes, of which the frontal is directed upward, the alveolar is directed downward, the palatine is directed medially, and the zygomatic is laterally. Despite the significant volume, the upper jaw is very light, since in its body there is a cavity - sinus, sinus maxillaris (volume 4-6 cm3). This is the largest sinus among those in (Fig. 1-8,1-9, 1-10).

Rice. 1-8.:

1 - frontal process, processus frontalis; 2 - front surface, facies anterior

Rice. 1-9. The structure of the right upper jaw, maxilla (view from the lateral side): 1 - frontal process, processus frontalis; 2 - infraorbital margin; 3 - infraorbital foramen, foramen infraorbitale; 4 - nasal notch, incisura nasalis; 5 - canine fossa, fossa canina; 6 - anterior nasal spine, spina nasalis anterior; 7 - alveolar elevations, juga alveolaria; 8 - incisors; 9 - canine; 10 - premolars; 11 - molars; 12 - alveolar process, processus alveolaria; 13 - zygomatic process, processus zygomaticus; 14 - alveolar openings, foramina alveolaria; 15 - tubercle of the maxillary bone, tuber maxillare; 16 - infraorbital groove; 17 - orbital surface of the body of the maxillary bone, facies orbitalis; 18 - lacrimal groove, sulcus lacrimalis

Rice. 1-10. : 1 - frontal process of the maxillary bone; 2 - lattice comb, crista ethmoidalis; 3 - lacrimal groove, sulcus lacrimalis; 4 - maxillary sinus, sinus maxillaris; 5 - large palatine sulcus; 6 - nasal crest; 7 - palatine grooves; 8 - alveolar process; 9 - molars; 10 - palatine process, processus palatinus; 11 - premolars; 12 - canine; 13 - incisors; 14 - incisive channel; 15 - anterior nasal spine, spina nasalis anterior; 16 - nasal surface (facies nasalis) of the maxillary bone; 17 - shell comb, crista conchalis

Body of the upper jaw(corpus maxillae) has 4 surfaces: anterior, infratemporal, orbital and nasal.

Front surface at the top it is limited by the infraorbital margin, below which there is an opening of the same name through which the vessels and nerves exit. This hole is 2-6 mm in diameter and is located at the level of the 5th or 6th teeth. Under this hole lies the canine fossa (fossa canim), which is the site of the beginning of the muscle that raises the corner of the mouth.

On the infratemporal surface there is a tubercle of the upper jaw (tuber maxillae), on which there are 3-4 alveolar openings leading to the roots of large molars. Vessels and nerves pass through them.

Orbital surface contains a lacrimal notch, limits the lower orbital fissure (fissura orbitalis inferior). At the posterior edge of this surface is the infraorbital sulcus (sulcus infraorbitalis), which passes into the canal of the same name.

nasal surface largely occupied by the maxillary cleft (hiatus maxillaris).

Alveolar process (processus alveolaris) . It is, as it were, a continuation of the body of the upper jaw from top to bottom and is an arcuately curved bone roller with a bulge facing anteriorly. The greatest degree of process curvature is observed at the level of the first molar. The alveolar process is connected by an intermaxillary suture with the process of the same name of the opposite jaw, from behind without visible borders it passes into the tubercle, medially into the palatine process of the upper jaw. The outer surface of the process, facing the vestibule of the mouth, is called the vestibular (facies vestibularis), and the inner, facing the sky, is called the palatine (facies palatinus). The arc of the process (arcus alveolaris) has eight dental alveoli (alveoli dentales) for the roots of the teeth. In the alveoli of the upper incisors and canines, the labial and lingual walls are distinguished, and in the alveoli of the premolars and molars, the lingual and buccal. On the vestibular surface of the alveolar process, each alveolus corresponds to alveolar elevations (juga alveolaria), most pronounced in the alveoli of the medial incisor and canine. The alveoli are separated from each other by bony interalveolar septa (septa interalveolaria). The alveoli of multi-rooted teeth contain inter-root partitions (septa interradicularia) that separate the roots of the tooth from each other. The shape and size of the alveoli correspond to the shape and size of the roots of the tooth. In the first two alveoli lie the roots of the incisors, they are cone-shaped, in the 3rd, 4th and 5th alveoli - the roots of the canine and premolars. They are oval in shape and slightly compressed from front to back. The canine alveolus is the deepest (up to 19 mm). In the first premolar, the alveolus is often divided by the interradicular septum into the lingual and buccal root chambers. In the last three alveoli, small in size, are the roots of the molars. These alveoli are divided by interradicular partitions into three root chambers, two of which face the vestibular, and the third - the palatal surface of the process. The vestibular alveoli are somewhat compressed from the sides, and therefore their dimensions in the anteroposterior direction are smaller than in the palatobuccal direction. The lingual alveoli are more rounded. Due to the variable number and shape of the roots of the 3rd molar, its alveolus is diverse in shape: it can be single or divided into 2-3 or more root chambers. At the bottom of the alveoli there is one or more openings that lead to the corresponding tubules and serve to pass the vessels and nerves. The alveoli are adjacent to the thinner outer plate of the alveolar process, which is better expressed in the region of the molars. Behind the 3rd molar, the outer and inner compact plates converge and form an alveolar tubercle (tuberculum alveolare).

The section of the alveolar and palatine processes of the upper jaw, corresponding to the incisors, in the embryo represents an independent incisor bone, which is connected to the upper jaw by means of an incisal suture. Part of the incisal suture at the border between the incisor bone and the alveolar process is overgrown before birth. The suture between the incisor bone and the palatine process is present in the newborn, and sometimes remains in the adult.

The shape of the upper jaw is individually different. There are two extreme forms of its external structure: narrow and high, characteristic of people with a narrow face, as well as wide and low, usually found in people with a wide face (Fig. 1-11).

Rice. 1-11. Extreme forms of the structure of the upper jaw, front view: A - narrow and high; B - wide and low

Maxillary sinus- the largest of the paranasal sinuses. The shape of the sinus basically corresponds to the shape of the body of the upper jaw. The volume of the sinus has age and individual differences. The sinus can continue into the alveolar, zygomatic, frontal and palatine processes. In the sinus, the superior, medial, anterolateral, posterolateral, and inferior walls are distinguished.

Materials used: Anatomy, physiology and biomechanics of the dental system: Ed. L.L. Kolesnikova, S.D. Arutyunova, I.Yu. Lebedenko, V.P. Degtyarev. - M. : GEOTAR-Media, 2009

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(maxilla), steam room, is located in the center of the face and connects with all its bones, as well as with the ethmoid, frontal and sphenoid bones (Fig. 1). The upper jaw takes part in the formation of the walls of the orbit, nasal and oral cavities, pterygo-palatine and infratemporal fossae. It distinguishes the body and 4 processes, of which the frontal is directed upward, the alveolar is directed downward, the palatine is directed medially, and the zygomatic is laterally. Despite the significant volume, the upper jaw is very light, since there is a cavity in its body - maxillary sinus.

Body of the upper jaw(corpus maxillaris) has the shape of a truncated pyramid. It distinguishes 4 surfaces: anterior, infratemporal, orbital and nasal.

Front surface (fades anterior) somewhat concave, limited at the top infraorbital margin (margo infraorbitalis), laterally - by the zygomatic-alveolar crest and zygomatic process, below - by the alveolar process and medially - nasal notch (incisura nasalis). Below the infraorbital margin is infraorbital foramen, through which the vessels and nerves of the same name exit. The infraorbital foramen, 2–6 mm in diameter, is usually semi-oval, rarely oval or in the form of a slit, sometimes double. In isolated cases, it is covered with a bone spike. Located at the level of the 5th or between the 5th and 6th teeth, but may be displaced to the level of the 4th tooth. Beneath this hole lies canine fossa (fossa canina), which is the site of the beginning of the muscle that raises the corner of the mouth.

Infratemporal surface (fades infratemporalis) convex, participates in the formation of the walls of the infratemporal and pterygo-palatine fossae. It distinguishes a more convex part - maxillary tubercle (tuber maxillae), which has 3-4 posterior superior alveolar openings (foramina alveolaria superiora posteriora). These holes lead to tubules that run in the wall of the maxillary sinus and are directed to the roots of the large molars. The corresponding alveolar vessels and nerves pass through these openings and tubules (see Fig. 1).

Rice. 1. Upper jaw, right:

a — topography of the upper jaw;

b - right side view: 1 - frontal process; 2 - front lacrimal crest; 3 - lacrimal groove; 4 - infraorbital margin; 5 - infraorbital foramen; 6 - nasal notch; 7 - anterior nasal spine; 8 - front surface; 9 - canine fossa; 10 - alveolar elevations; 11 - alveolar arch; 12 - body of the upper jaw; 13 - zygomatic-alveolar crest; 14 - rear upper alveolar openings; 15 - infratemporal surface; 16 - tubercle of the upper jaw; 17 - zygomatic process; 18 - infraorbital groove; 19 - infraorbital surface; 20 - lacrimal notch;

c - view from the side of the nasal surface: 1 - frontal process; 2 - front lacrimal crest; 3 - lacrimal groove; 4 - cleft of the maxillary sinus; 5 - a large palatine sulcus; 6 - nasal crest; 7 - alveolar process; 8 - alveolar arch; 9 - incisive channel; 10 - palatine process; 11 - nasal surface of the upper jaw; 12 - shell comb; 13 - lattice comb;

d - bottom view: 1 - incisive fossa and incisal holes; 2 - incisive bone; 3 - incisive suture; 4 - palatine process; 5 - zygomatic process; 6 - palatine furrows; 7 - palatine ridges; 8 - alveolar process; 9 - inter-root partitions; 10 - interalveolar septa; 11 - dental alveoli;

e - alveolar canals (opened): 1 - infraorbital canal; 2 - infraorbital foramen; 3 - anterior and middle alveolar canals; 4 - rear alveolar canals; 5 - rear upper alveolar openings; 6 - maxillary sinus (opened)

Orbital surface (fades orbitalis) smooth, triangular in shape, participates in the formation of the lower wall of the orbit. Anteriorly, it ends at the infraorbital margin, laterally connected to the orbital surface of the zygomatic bone. The medial edge of the orbital surface connects in front with the lacrimal bone, for which there is a lacrimal notch (incisura lacrimalis). Behind the medial edge is connected to the orbital plate of the ethmoid bone. In some cases, it bifurcates and forms cells that complement the cells of the lattice labyrinth. The orbital process of the palatine bone is adjacent to the posterior end of the medial margin. Behind the orbital surface, together with the edge of the large wing of the sphenoid bone, limits inferior orbital fissure (fissura orbitalis inferior). From the middle of the posterior edge of the orbital surface stretches forward infraorbital sulcus, which passes into the canal of the same name, which opens with the infraorbital foramen. On the lower wall of the canal are small anterior and middle upper alveolar openings (foramina alveolaria superiora media et anteriora) leading to small bone canals reaching the roots of the front and middle teeth. Vessels and nerves pass through them to the teeth.

Nasal surface (fades nasalis) forms a large part of the lateral wall of the nasal cavity (see Fig. 1). It articulates posteriorly with the perpendicular plate of the palatine bone, and anteriorly and superiorly with the lacrimal bone. A significant part of this surface is occupied by the opening of the maxillary sinus - maxillary cleft (hiatus maxillaris). Anterior to the cleft is a vertically directed lacrimal groove (sulcus lacrimalis), which, together with the lacrimal bone and the lacrimal process of the inferior turbinate, forms nasolacrimal canal opening into the nasal cavity. Below and anterior to the lacrimal sulcus is a horizontal protrusion - shell comb (crista conchalis) for connection with the anterior end of the inferior turbinate. Behind the maxillary cleft there is a vertically directed greater palatine sulcus (sulcus palatinus major), which is part of the walls of the greater palatine canal.

Human Anatomy S.S. Mikhailov, A.V. Chukbar, A.G. Tsybulkin