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How are the bones of the skull connected to each other? Skull: the connection between the bones of the skull. Types of joints of the skull bones Which skull bone is attached with a joint

Ministry of Health and Social Development

Chita State Medical Academy

Department of Normal Human Anatomy

“Connection of skull bones”

Completed by: student of group 132

Nimaeva S.M.

Checked by: Doctor of Medical Sciences, Professor

Melnikova S.L.

Connection of bones to each other and to the skull

The methods of connecting bones are very different. They can be divided into two main groups:

synarthrosis (synarthrosis), i.e. continuous connection of bones through connective tissue or cartilage, and in this case there is usually no cavity between the connecting bones;

diarthrosis (dyarthrosis), a true joint, or articulation (articulatio), when the bones are just in contact with their articular surfaces, always in this kind of joint, covered with a layer of cartilage (hyaline), and the ligaments, called synodal and holding the bones in contact with one another, are outside, around the circumference of the articular surfaces, so that a cavity called synovial is formed between the bones. On the inside it is lined with a thin synovial membrane, which secretes sticky, transparent, yellowish synovial fluid. Near the true joint there are often additional ligaments located along its outside. It is obvious that the mobility of the joints in cases I and II is very different.

Synarthrosis is the least perfect joint. It can be considered the original form for diarthrosis - and can be divided into the following types:

a) Syndesmosis, characterized by the fact that the connection of bones is accomplished through tendon tissue, running in the form of ligaments from one bone to another and constituting a continuation of the periosteum of both bones. Since syndesmosis is formed simultaneously with the separation of bones, a certain amount of connective tissue that was not used to form both bones remains between them in the form of a layer connecting them. The mobility of this kind of joint is greater, the smaller the plane of contact of the bones and the more developed the layer of intermediate tissue located between them. When the bones are more or less far from one another, this tissue forms between them a kind of interosseous plate, which indicates the initial mutual relationship of the bones. If the intermediate layer is very limited, then the bones are in close contact with one another and then they are embedded into one another with the help of teeth or combs. This modification of the syndesmosis is known as a suture (sutura).

b) Synchondrosis (synchondrosis) or such a connection when between the articular surfaces of the bones there is cartilage, representing for the most part a remnant of the original cartilage, preserved between some parts of the skeleton and not replaced by bone. This is the so-called true synchondrosis. In other cases, with synchondrosis, such a modification of the intermediate cartilage is possible that only those parts of it that are in direct contact with the articular surfaces of the bones retain their original structure, while the rest of it takes on the structure of fibrocartilage. Sometimes parts of the cartilage may even loosen, so that a cavity forms in the center. This kind of connection is called false synchondrosis.

c) Synostosis - fusion of bones initially separated from one another, which occurs with age. These bones can be connected at an early age, both with the help of synchondrosis and with the help of syndesmosis. In both cases, synostosis is the result of ossification of the intermediate layer.

Connection of skull bones

The bones that form the skull are connected to each other using continuous joints. The exception is the connection of the lower jaw with the temporal bone to form the temporomandibular joint. Continuous connections between the bones of the skull are represented mainly by fibrous connections in the form of sutures in adults and interosseous membranes (syndesmoses) in newborns. At the level of the base of the skull there are cartilaginous connections called synchondroses.

The bones of the roof of the skull are connected to each other using serrated and scaly sutures. Thus, the medial edges of the parietal bones are connected by a serrated sagittal suture, sutura sagitalis, the frontal and parietal bones are connected by a serrated coronal suture, sutura coronalis, and the parietal and occipital bones are connected by a serrated lambdoid suture, sutura lambdoidea. The scales of the temporal bone are connected to the parietal bone and the greater wing of the sphenoid bone using a scaly suture. There are flat (harmonious) sutures between the bones of the facial skull. The names of individual sutures on the skull are derived from the names of the two connecting bones, for example: frontoethmoidal suture, sutura frontoethmoidalis, temporomygomatic suture, sutura temporozygomatica, etc. There are also non-permanent sutures formed as a result of non-fusion of individual ossification points.

Cartilaginous joints - synchondrosis - in the area of the base of the skull are formed by fibrous cartilage. These are connections between the body of the sphenoid bone and the basilar part of the occipital bone - sphenoid-occipital synchondrosis, synchondrosis sphenooccipitalis, between the pyramid of the temporal bone and the basilar part of the occipital bone - petrooccipital synchondrosis, synchondrosis petrooccipitalis, etc. Usually, with age, a person experiences replacement of cartilage tissue bone In place of the sphenoid-occipital synchondrosis, synostosis is formed (by the age of 20).

Synovial joints of the skull (joints of the skull)

Temporomandibular joint

The temporomandibular joint (articulatio temporomandibularis) is paired, complex in structure, ellipsoidal. Its articular surfaces are the head of the mandible (caput mandibulae) and the mandibular fossa (fossa mandibularis) of the temporal bone. Fibrous articular cartilage covers the mandibular fossa only anterior to the petrotympanic fissure and the entire articular tubercle. The head of the lower jaw is covered with articular cartilage only in its anterosuperior part.

Congruence of the articular surfaces is achieved due to the articular disc (discus articularis), which has the shape of a round biconcave lens. The central part of the disc is thinner than the peripheral part.

The articular capsule is cone-shaped, its wide base facing upward. Here on the temporal bone it is attached anterior to the articular tubercle, and posteriorly at the level of the petrotympanic fissure. On the condylar process, the capsule is attached in front along the edge of the head, and in the back - 0.5 cm below the posterior edge of the head of the mandible. In front, the articular capsule is thinner than in the back, and is fused along the entire circumference with the articular disc in such a way that the articular cavity is divided into two floors, isolated from each other. In the upper floor, the articular surface of the temporal bone articulates with the upper surface of the articular disc. The upper synovial membrane, membrana synovialis superior, covers the inner surface of the capsule and is attached along the edge of the articular cartilage. In the lower floor the head of the mandible and the lower surface of the articular disc articulate. The lower synovial membrane, membrana synovialis inferior, covers not only the capsule, but also the posterior surface of the neck of the condylar process, located inside the capsule.

On the lateral side, the capsule is strengthened by the lateral ligament, lig. laterale. It is fan-shaped and starts from the base of the zygomatic process of the temporal bone. The fibers of this ligament run posteriorly and inferiorly and are attached to the posterolateral surface of the neck of the condylar process.

The lateral ligament inhibits the posterior movement of the articular head.

The auxiliary ligaments of the temporomandibular joint are also thickened fascial cords located medially, outside the joint. This is the sphenomandibular ligament, lig. sphenomandibulare, and stylomandibular ligament, lig. stylomandibulare. The first begins in the form of a thin fibrous cord from the spine of the sphenoid bone and is attached to the lingula of the lower jaw; the second spreads from the styloid process to the inner surface of the posterior edge of the ramus of the lower jaw (near the angle of the lower jaw).

Movement in the right and left temporomandibular joints occurs together, so functionally they form a single combined joint. The following types of movements are possible in the joint:

1) lowering and raising the lower jaw, corresponding to the opening and closing of the mouth;

2) displacement of the lower jaw forward (progression) and backward (return to its original position); 3) movements of the jaw to the right and left (lateral movements).

When lowering the lower jaw, the chin protuberance moves downwards and somewhat backwards, describing an arc with its concavity facing backwards and upwards. This movement can be divided into three phases. In the first phase (slight lowering of the lower jaw), movement around the frontal axis occurs in the lower floor of the joint, the articular disc remains in the articular fossa. In the second phase (significant lowering of the lower jaw), against the background of the continuing hinge movement of the articular heads in the lower floor of the joint, the cartilaginous disc, together with the head of the articular process, slides forward and emerges onto the articular tubercle. The condylar process of the mandible moves anteriorly by approximately 12 mm. In the third phase (maximum lowering of the jaw), movement occurs only in the lower level of the joint around the frontal axis. The articular disc is located on the articular tubercle at this time.

With a significant opening of the mouth, the head of the lower jaw may slip anteriorly from the articular tubercle, into the infratemporal fossa, and dislocate the joint. The mechanism for raising the lower jaw repeats the stages of its lowering in reverse order.

If the lower jaw moves forward, the movement occurs only in the upper floor of the joint. The articular processes, together with the articular discs, slide forward and extend onto the tubercle in both the right and left temporomandibular joint.

With the lateral displacement of the lower jaw, the movements in the right and left temporomandibular joints are not the same: when the lower jaw moves to the right in the left temporomandibular joint, the articular head, together with the disc, slides anteriorly and extends onto the articular tubercle, i.e. sliding occurs in the upper floor of the joint. At this time, in the joint of the right side, the articular head rotates around a vertical axis passing through the neck of the condylar process. When the lower jaw moves to the left, the head, together with the articular disc, slides forward in the right joint, and rotation around the vertical axis occurs in the left.

The sutures of the bones of the human skull are strong connections that anatomically unite various elements into a single cranium. To ensure mobility of the lower jaw, there are special joints of the skull; they are located symmetrically and are mainly responsible for chewing and speaking functions. The sutures of a person’s skull may have an incorrect configuration after connective tissue diseases suffered in childhood.

Cranial sutures

Cranial sutures are predominantly fibrous joints. In the area of the facial part of the skull the sutures are even, smooth, flat (harmonious), and in the area of the brain they are jagged; between the parietal bone and the scales of the temporal bone there is a scaly suture. At the base of the child’s skull there are synchondroses, for example, sphenoid-occipital, sphenoid-petrosal, petro-occipital, which ossify with age, turning into synostoses. Only the lower jaw forms a synovial joint with the skull - the temporomandibular joint, supported by ligaments.

Joints of the skull

Synovial joints are joints of the skull that have a very limited range of motion in two planes. The temporomandibular joint is paired, combined, complex, ellipsoidal. Its articular surfaces are formed by the head of the mandible and the mandibular fossa of the temporal bone together with the articular tubercle.

The correspondence (congruence) of the articular surfaces on the mandible and the temporal bone is achieved through an articular disc, which has the shape of a biconcave round lens built from fibrous cartilage. Fusing with the joint capsule along the periphery, the disc divides its cavity into upper and lower parts. The disc moves with the head of the lower jaw. A very loose articular capsule, as well as a significantly larger articular fossa (the area of the articular fossa is 2-3 times larger than the head of the mandible) provide greater mobility of the temporomandibular joint. On the lateral side, the joint capsule is strengthened by a single fan-shaped lateral ligament, which begins at the base of the zygomatic process of the temporal bone and is attached to the neck of the condylar process: the mandible. The ligament not only strengthens the joint, but also inhibits backward and sideways movements of the lower jaw. Movement in the right and left temporomandibular joints occurs together.

Bones of the skull connected by joints

The bones of the skull that are connected by joints include the mandible and the temporal bone. The following types of movements are performed in these joints: lowering and raising the lower jaw, corresponding to the opening and closing of the mouth; displacement of the lower jaw forward (progression) and backward (return to its original position); movement of the jaw to the right and left. The lowering and raising of the lower jaw occurs around the frontal axis in the lower floor of the joint. The displacement of the lower jaw occurs in the upper floor of the joint; with this movement, the head of the lower jaw, together with the disc, emerges from the articular fossa onto the tubercle. During lateral movements, the head of the lower jaw comes out onto the tubercle only on one side, while the head of the other side remains in the articular cavity and rotates around a vertical axis.

The connections of the bones of the brain skull are carried out due to fibrous connective tissue, which forms fontanelles in a newborn, and sutures in children and adults (see Sutures of the skull).

The temporomandibular joint (articulatio temporomandibularis) is formed by connecting the head of the mandible and the articular fossa of the temporal bone (Fig. 115). The joint has an articular disc (discus articularis), which fuses with the joint capsule and divides its cavity into upper and lower parts.

115. The structure of the temporomandibular joint (the joint is opened).

1 - fossa mandibularis;
2 - discus articularis;
3 - processus articularis;
4 - lig. stylomandibulare.

The head of the lower jaw has the shape of an ellipse. The axis drawn along the length of the articular processes is not projected strictly in the frontal plane. Ultimately, the right and left joint axes intersect in front of the foramen magnum at an angle of 160°.

The glenoid fossa is significantly larger than the articular head. The fossa is limited by: in front - the articular tubercle, behind - the lower wall of the external auditory canal, outside - the beginning of the zygomatic process, from the inside - the gap between the pyramid and the scales of the temporal bone and the angular spine of the sphenoid bone, on top - a thin bone plate separating the joint cavity from the middle cranial fossa .

The anterior intracapsular part of the articular fossa is covered with cartilage up to the petrotympanic fissure (fissura petrotympanica). The posterior part of the fossa is located outside the joint capsule, behind this gap. The area of the articular fossa is 2-3 times larger than the head of the lower jaw, which provides greater mobility of the temporomandibular joint. The depth of the articular fossa is influenced by the height of the articular tubercle, which on average has a posterior inclination of 35°, facing the joint cavity. The amount of inclination depends on the dental bite. If we draw a line parallel to the surface of the inclination of the articular tubercle, it will end in the gap between the large molars. Therefore, in a toothless jaw, the inclination of the articular tubercle is rearranged and the depth of the articular fossa changes. And, conversely, when wearing dentures, it takes time for the shape and depth of the articular fossa to adjust to the appropriate bite and the denture to become more comfortable.

The articular disc (discus articularis) is built of fibrous cartilage fused to the articular capsule. Its characteristic feature is that the disc moves along with the head of the lower jaw. This is due to the fact that the joint capsule, located between the disc and the neck of the lower jaw, is stronger, more stretched, and bundles of the lateral pterygoid muscle are woven into it from the inside. These muscles move the lower jaw forward.

The articular capsule (capsula articularis) is very loose. At the bottom it is attached to the neck of the articular process, at the base of the skull the border of attachment of the capsule runs along the anterior surface of the articular tubercle, then from the inside at the spina angularis of the sphenoid bone, from behind it reaches the fissura petrotympanica and from the outside it is attached to the base of the zygomatic process.

Ligaments. The temporomandibular joint is strengthened by a single lateral ligament (lig. laterale), which starts from the beginning of the zygomatic process and goes down and back to the neck of the condylar process of the mandible (Fig. 116). It not only strengthens the joint, but also inhibits backward and sideways movement. There are three more bundles of thickened fascia that suspend the lower jaw. These bundles are conventionally called ligaments. The stylomandibular ligament (lig. stylomandibulare) starts from the styloid process and reaches the angle of the mandible. The second ligament, the sphenoid-maxillary (lig. sphenomandibulare), originates from the spina angularis of the sphenoid bone and is attached to the lingula of the lower jaw. The third ligament, the pterygomandibular ligament (lig. pterygomandibulare), is a short, fine-fiber bundle. It starts from the hook of the pterygoid process and is attached to the base of the uvula of the lower jaw (Fig. 117). All three ligaments form a loop on which the lower jaw is suspended and the head is held in the glenoid fossa. The lower jaw represents a double-armed lever, and the center of its rotation is located at the place of attachment of the ligaments to the uvula of the lower jaw (Fig. 118). They also prevent the hinge movement in the glenoid fossa during significant and maximum lowering of the jaw. In this case, the condylar process, together with the disc, is forced to slide onto the articular tubercle (Fig. 119).

116. Ligaments of the temporomandibular joint.

1 - lig. temporomandibulare;
2 - lig. stylomandibulare.

117. Ligaments of the temporomandibular joint.

1 - lig. sphenomandibulare;
2 - lig. stylomandibulare;
3 - lig. pterygospinale.

118. The lower jaw is like a lever (according to V.P. Vorobyov).

1 - m. pterygoideus lateralis;
2 - m. digastricus;
3 - os hyoideum;
4 - m. stylohyoideum;
5 - lig. sphenomandibulare;
6 - lig. stylomandibulare.

119. Scheme of sliding of the disc and head of the lower jaw onto the articular tubercle with significant lowering of the lower jaw (according to Schroder).

Both temporomandibular joints function together (combined joint). During the act of chewing, the lower jaw lowers, rises, moves forward and backward, to the sides. Thanks to the special structure of the joints, a variety of movements are possible, which in the form of separate elements are performed in the joints of various animals - ruminants, rodents and predators. The head of the lower jaw in predators is long and located in the frontal plane and sits deep in the articular fossa. This structure allows only the lowering and raising of the jaw around the frontal axis. Thus, predators can only bite off food.

This function has been preserved in humans. The lower jaw moves down and up in an arc of 35°. Ruminants have a flat mandibular joint. With such a structure, mainly lateral movements of the jaw are carried out, aimed at grinding coarse plant food with the molars. In humans, the glenoid fossa is filled with a disc, which allows the lower jaw to move laterally and chew. In rodents, the articular head of the lower jaw is rotated 90° compared to predators and is located in the form of long ridges in groove-like pits in the sagittal plane. With such a structure, jaw movements forward and backward are possible. These movements limit the incisors. In humans, it is also possible for the lower jaw to move forward and backward with a total range of 8 to 12 mm due to the displacement of the disc. Thus, when analyzing the movements of the jaw of various animal species, we see that the human temporomandibular joint is universal. This is ensured by the articular disc and special muscle attachments.

The nature of movement in the temporomandibular joint depends on the amount of lowering of the jaw. With minor movements - lowering the jaw by 1 -1.5 cm (quiet speech) the articular heads rotate in the articular fossa around the frontal axis. When performing a more significant movement, when the distance between the incisors increases to 4 cm, not only rotation of the head in the back of the joint is observed, but also its movement together with the articular disc to the middle of the articular tubercle.

With the maximum lowering of the lower jaw, its articular head ultimately performs the final hinge movement at the apex of the articular tubercle. Further sliding of the articular disc and articular head is delayed by tension in the lateral ligament. When lowering the lower jaw, the head together with the disc may move forward from the top of the articular tubercle. In this case, dislocation of the lower jaw is possible.

Lateral movements occur when the head and disc are unilaterally displaced forward, and on the opposite side of the joint there is a rotation around the vertical axis of the head. Alternating lateral movements of 15° with lowering and raising the jaw forms the act of chewing. In this case, the lower jaw describes a line in the form of an oval with a large vertical diameter (Fig. 120).

120. Scheme of the direction of movement in each phase of chewing (indicated by arrows).

O - initial position;
I - opening phase;
II - phase of displacement to the side;
III - beginning of closure;
IV - return to the starting position.

Scull formed by paired and unpaired bones, firmly connected by sutures. It serves as a container and support for vital organs.

The cavities formed by the bones of the skull contain the brain, as well as the organs of vision, hearing, balance, smell, and taste, which are the most important sense organs. The cranial nerves exit through numerous openings in the bones of the base of the skull, and the arteries that supply them pass to the brain and other organs.

The skull consists of two sections: the brain and the facial. The section in which the brain is located is called brain skull. The second section, which forms the bone base of the face, the initial parts of the digestive and respiratory systems, is called facial skull(Fig. 22, 23).

Rice. 22. Structure of the human skull (side view):

1 - parietal bone, 2 - coronal suture, 3 - frontal bone, 4 - sphenoid bone, 5 - ethmoid bone, 6 - lacrimal bone, 7 - nasal bone, 8 - temporal fossa, 9 - anterior nasal bone, 10 - upper jaw , 11 – lower jaw, 12 – zygomatic bone, 13 – zygomatic arch, 14 – styloid process, 15 – condylar process, 16 – mastoid process, 17 – external auditory canal, 18 – lamdoid suture, 19 – occipital bone, 20 – temporal lines, 21 – temporal bone

Rice. 23. Structure of the human skull (front view):

1 - coronal suture, 2 - parietal bone, 3 - orbital part of the frontal bone, 4 - sphenoid bone, 5 - zygomatic bone, 6 - inferior nasal concha, 7 - upper jaw, 8 - mental protuberance of the lower jaw, 9 - nasal cavity, 10 – vomer, 11 – ethmoid bone, 12 – upper jaw, 13 – lower orbital fissure, 14 – lacrimal bone, 15 – ethmoid bone, 16 – upper orbital fissure, 17 – temporal bone, 18 – zygomatic process of the frontal bone, 19 – optic canal, 20 – nasal bone, 21 – scales of the frontal bone.

The brain section of the skull of adults is formed by the frontal, sphenoid, occipital, parietal, temporal and ethmoid bones.

Frontal bone in adults, unpaired. It forms the anterior part of the cranium and the upper wall of the orbits. It distinguishes the following parts: frontal scales, orbital and nasal parts. In the thickness of the bone there is a frontal sinus that communicates with the nasal cavity.

Sphenoid bone located in the center of the base of the skull. It has a complex shape and consists of a body from which three pairs of processes extend: large wings, small wings and pterygoid processes. In the body of the bone there is a sinus (sphenoid), which also communicates with the nasal cavity.

Occipital bone forms the posterior-inferior part of the brain skull. It consists of a main part, lateral masses and occipital scales. All these parts surround the foramen magnum, through which the brain connects to the spinal cord.

Parietal bone steam room, forms the upper lateral section of the cranial vault. It is a quadrangular plate, convex from the outside and concave from the inside.

Ethmoid bone unpaired, participates in the formation of the walls of the orbits and nasal cavity. The following parts are distinguished in it: a horizontally located lattice plate having numerous small holes; a perpendicular plate involved in dividing the nasal cavity into the right and left halves; ethmoid labyrinths with the superior and middle nasal conchae, forming the lateral walls of the nasal cavity.

Temporal bone steam room It participates in the formation of the joint with the lower jaw. The temporal bone is divided into pyramid, tympanic and squamosal parts. Inside the pyramid there is a sound-receiving apparatus, as well as a vestibular apparatus that detects changes in the position of the body in space. In the pyramid of the temporal bone there is the cavity of the middle ear - the tympanic cavity with the auditory ossicles located in it and the miniature muscles acting on them. On the lateral surface of the temporal bone there is an opening for the external auditory canal. The temporal bone is pierced by several canals in which nerves and blood vessels pass (carotid canal for the internal carotid artery, canal of the facial nerve, etc.).

Facial part of the skull. The bones of the facial part of the skull are located under the brain. A significant part of the facial skull is occupied by the skeleton of the masticatory apparatus, represented by the upper and lower jaws.

Upper jaw – a paired bone involved in the formation of the lower wall of the orbit, the lateral wall of the nasal cavity, the hard palate, the opening of the nose. The upper jaw has a body and four processes: frontal, zygomatic, palatine and alveolar, which bears alveoli for the upper teeth.

Lower jaw - The unpaired bone is the only movable bone of the skull, which, connecting with the temporal bones, forms the temporomandibular joints. The lower jaw has a curved body with alveoli for the lower teeth, coronoid processes for attaching one of the masticatory muscles (temporal) and articular processes.

Nasal cavity

The rest, the so-called small bones of the face (paired palatines, inferior nasal concha, nasal, lacrimal, zygomatic, and unpaired vomer) are small in size and are part of the walls of the orbits, nasal and oral cavities. The bones of the skull also include the arched hyoid bone, which has paired processes - the upper and lower horns.

Connections of the bones of the skull. All bones of the skull, with the exception of the lower jaw and hyoid bone, are fixedly connected to each other using sutures. For ease of study, the upper part of the brain skull is isolated - vault, or roof of the skull and the lower part - base of skull.

Skull roof bones connected by continuous fibrous connections - seams, the bones of the base of the skull form cartilaginous joints - synchondrosis. The frontal, parietal, and occipital bones form jagged sutures; the bones of the facial skull are connected using flat, harmonious sutures. The temporal bone is connected to the parietal and sphenoid bones using a scaly suture. In adulthood, cartilage joints at the base of the skull are replaced by bone tissue - neighboring bones grow together.

The lower jaw forms a pair with the temporal bone temporomandibular joint. The formation of this joint involves the articular process of the lower jaw and the articular surface on the temporal bone. This joint is ellipsoidal in shape, complex in structure, combined in function. Inside the joint there is an intra-articular disc, fused along the periphery with the articular capsule and dividing the articular cavity into two floors: upper and lower. The temporomandibular joint performs the following movements: lowering and raising the lower jaw, moving the jaw to the sides, shifting the lower jaw back and forth.

The skull has a complex topography of both the outer and inner surfaces, due to the location in its bony cavities of the brain (cranial cavity), organs of vision (orbit), smell (nasal cavity), taste (oral cavity), hearing and balance (tympanic cavity and labyrinths of the inner ear).

In the front part of the skull (art. Fig. 23) there are eye sockets, in the formation of which the upper jaws, frontal, zygomatic, sphenoid and other bones participate. Above the eye sockets is the anterior surface of the frontal bone with the brow ridges. Between the eye sockets is the bony dorsum of the nose, formed by the nasal bones, and below is the anterior opening (aperture) of the nasal cavity. Even lower, arched alveolar processes of the fused maxillary bones and lower jaw with teeth located in the alveoli are visible.

nasal cavity, which is the bony skeleton of the beginning of the respiratory tract, has an inlet opening (aperture) in front, and two outlet openings in the back - choanae. The upper wall of the nasal cavity is formed by the nasal bones, the cribriform plate of the ethmoid bone, the body of the sphenoid bone and the frontal bone. The lower wall is represented by the upper surface of the bony palate. On the lateral surfaces formed by the maxillary and other bones, three curved plates are visible - the upper, middle and lower turbinates.

On the lateral surface of the skull (see Fig. 22) visible zygomatic arch, which connects the zygomatic bone in front with the temporal bone in the back and external auditory canal with the mastoid process located behind it, directed downward. Above the zygomatic arch there is a depression - temporal fossa, where the temporal muscle originates, and below the arch - deep infratemporal fossa, as well as the processes of the lower jaw.

At the back of the skull, the external occipital protuberance protrudes posteriorly.

Lower surface of the skull has a complex terrain. Ahead is solid sky, bounded anteriorly and laterally by the alveolar arch with the upper teeth. Visible behind and above the hard palate choanae – the posterior openings of the nasal cavity, connecting this cavity with the pharynx. On the lower surface of the occipital bone there are two condyles for connection with the first cervical vertebra, and between them - foramen magnum. On the sides of the occipital bone one can see a complex relief of the lower surface of the temporal bones with openings for the passage of nerves and blood vessels, an articular fossa and anterior to it a tubercle for articulation with the articular processes of the lower jaw.

Inner surface of the base of the skull has a relief corresponding to the lower surface of the brain. Three cranial fossae are visible here - anterior, middle and posterior. The frontal lobes of the brain are located in the anterior cranial fossa, formed by the frontal and ethmoid bones. The middle cranial fossa is formed by the sphenoid and temporal bones. It contains the temporal lobes of the brain, and the pituitary fossa contains the pituitary gland. In the posterior cranial fossa, bounded by the occipital and temporal bones, are the cerebellum and occipital lobes of the brain.

Sutures of the skull, suturae cranii (craniales).
Coronal suture, sutura coronalis. Located between the frontal and two parietal bones. Rice. A, B, G.
Sagittal suture, sutura sagittalis. Located in the midline between the right and left parietal bones. Rice. IN.
Lambdoid suture, sutura lambdoidea. Located between the occipital and two parietal bones. Rice. A, G.
Occipitomastoid suture, sutura oscipitomastoidea. Continuation of the lambdoid suture to the base of the skull. Rice. A, G.
Sphenoid-frontal suture, sutura sphenofrontal. Located between the greater wing of the sphenoid bone and the frontal bone. At the base of the skull it passes between the frontal and lesser wing of the sphenoid bone. Rice. A, B, G.
Wedge-ethmoid suture, sutura sphenoethmoidalis. It is located anterior to the sphenoid eminence between the body of the os sphenoidale and the ethmoid bone. Rice. G.
Wedge-squamous suture, sutura sphenosquamosa. Located between the temporal scales and the greater wing of the sphenoid bones. Rice. A, B, G.
Sphenoparietal suture, sutura sphenoparietal. Located between the greater wing of the sphenoid bone and the os parietale. Rice. A, B, G.
Scaly suture, sutura squamosa. Located between the temporal and parietal bones. Rice. A, B, G.
[Frontal (metopic suture), sutura frontalis (metopica). Located between the two halves of the scales of the frontal bone, which fuse into a single whole by the age of six. Rice. IN.
Parietomastoid suture, sutura parietomastoidea. Located between the parietal bone and the mastoid process. Rice. A.
[Squamomastoid suture, sutura squamosontastoidea]. It is determined between the mastoid process and the os temporale scales only in early childhood. Rice. A.
Frontonasal suture, sutura frontonasalis. Located between the frontal and nasal bones. Rice. IN.
Frontoethmoidal suture, sutura frontoethmoidalis. The junction of the orbital plate of the ethmoid and frontal bones. Rice. B, G.
Frontomaxillary moa, sutura frontomaxillaris. Located between the frontal process of the maxilla and the nasal part of the frontal bone. Rice. A B C.
Frontolacrimal suture, sutura frontolacrimalis. Connection between the lacrimal and frontal bones. Rice. A B C.
Frontozygomatic suture, sutura frontozygomatica. Located at the lateral edge of the orbit between the frontal and zygomatic bones. Rice. A B C.
Zygomaticomaxillary suture, sutura zygomaticomaxillaris. Passes on the lower wall of the orbit between the frontal and zygomatic bones. Rice. A B C.
Ethmoidomaxillary suture, sutura ethmoidomaxillaris. Located on the medial wall of the orbit between the orbital plate of the ethmoid bone and the upper jaw. Rice. B, V.
Ethmoidolacrimal suture, sutura ethmoidolacrimalis. Located between the orbital plate, the ethmoid bone and the lacrimal bone. Rice. B.
Wedge-vomer suture, sutura sphenovomeriana. Located in the nasal septum between the sphenoid bone and the vomer.
Sphenozygomatic suture, sutura sphenozygomatica. Passes in the lateral wall of the orbit between the greater wing of the os sphenoidale and the zygomatic bone. Rice. B, V.
Sphenomaxillary suture, sutura sphenomaxillaris. Located between the pterygoid process and the upper jaw. Not constantly present. Rice. A.
Temporozygomatic suture, sutura temporozygomatica. Located between the zygomatic bone and the zygomatic process os temporale. Rice. A.
Internasal suture, sutura internasalis. Connection of two nasal bones. Rice. IN.
Nasomaxillary suture, sutura nasomaxillaris. Connection of the nasal bone and the frontal process of the maxilla. Rice. A V.
Lacrimal-maxillary suture, sutura lacrimomaxillaris. Located between the anterior edge of the lacrimal bone and the upper jaw. Rice. A B C.
Lacrimal-conchal suture, sutura lacrimoconchalis. It is located on the wall of the nasal cavity between the nasal bone and the inferior turbinate.
Intermaxillary suture, sutura intermaxillaris. Midline connection between the two maxillae. Rice. IN.
Palatomaxillary suture, sutura palatomaxillaris. Located in the posterior part of the orbit and on the lateral wall of the nasal cavity between the orbital process of the palatine bone and the upper jaw. Rice. B.
Palatoethmoidal suture, sutura palatoethmoidal. It is located between the orbital process of the palatine and the orbital plate of the ethmoid bones. Rice. B.
Median palatal suture, sutura palatina mediana. Connection of the two halves of the bony palate. Rice. D.
Transverse palatal suture, sutura palatina transversa. Located between the palatine processes of the upper jaw and the horizontal plates of the palatine bones. Rice. D.