In humans, the bones of the roof of the skull belong to. The bones of the skull and their joints. Water-soluble vitamins include

Lecture 4

Theme: Head skeleton.

Questions:

1. General characteristics of the skull and its parts.

2. The structure of the bones of the brain.

3. Anatomy of the bones of the facial region of the skull.

General characteristics of the skull and its parts.

Human skull(lat. cranium) - bone skeleton of the head, a set of bones. The human skull is formed by 23 bones, in addition to which there are three paired auditory ossicles in the middle ear cavity - the malleus, incus and stirrup, as well as 32 (28, 20; 4 x 8, 7 or 5) teeth on the upper and lower jaws.

The skull (Fig. 1-2) is the skeleton of the head and determines the features of its external shape. It is connected to the vertebral column by an atlas. The bones of the skull, connecting with each other, form a large number of cavities, depressions and pits.

The skull has the following functions:

Protective (contains the brain and sensory organs, protecting these formations from damage);

Support (serves as a receptacle for the brain, sensory organs, the initial sections of the digestive and respiratory systems);

Motor (articulated with the spinal column).

Rice. 1. The structure of the human skull (side view)

Rice. 2. The structure of the human skull (front view)

Skull structure

According to the features of the functional purpose, several departments are distinguished in the skull:

skull bones(cerebral skull) and bones of the face (facial skull). The cerebral department significantly predominates over the facial one.

On cerebral skull(cranium neurale (neurocranium) seu cranium cerebrale) distinguish the upper part of it - skull roof and the bottom part - base of skull.

Roof, or the cranial vault (calvaria seu fornix cranii). Roof bones are flat bones. The roof of the skull is composed of the parietal bones, partly the frontal, occipital and temporal bones;

Base of skull(basis cranii). The bones of the base of the skull are mixed bones, some of them are pneumatic - they contain air cavities (sinuses). The base of the skull is formed by the orbital parts of the frontal bone, ethmoid, sphenoid, temporal, and occipital bones. Distinguish between external (basis cranii externa) and internal base of the skull (basis cranii interna).

In education cerebral skull 8 bones take part: 4 unpaired (occipital, wedge-shaped, ethmoid and frontal) and 2 paired (temporal and parietal).

In education facial skull 6 paired bones are involved (upper jaw, zygomatic, palatine, nasal, lacrimal, lower nasal concha.) and 3 unpaired bones (vomer, lower jaw and hyoid), as well as ethmoid and sphenoid bones, which are the bones of the cerebral skull. In addition, the facial skull includes 3 paired auditory ossicles (malleus, incus, and stirrup), considered together with the auditory organ.

The structure of the bones of the brain.

Due to the development of his brain, the human brain's skull is larger in volume than the facial one, while all other representatives of the animal world have the facial skull larger than the cerebral one.

The bones of the cerebral skull are flat in shape(parietal, occipital) or air(frontal, wedge-shaped, lattice, temporal).

The inner surface of the bones that make up the cranial skull have large, fingerprint-like indentations that alternate with ridges. Depressions and protrusions correspond to the convolutions and grooves of the outer surface of the brain. In addition, on the inner surface of the bones of the skull there are grooves in which the arteries of the dura mater pass.

Occipital bone(os occipitale) takes part in the formation of the base of the skull and the posterior part of the skull roof. It consists of four parts located around large hole: in front - basilar part, from the sides - paired lateral parts, and behind - the occipital scales. In a large hole pass an oblong

brain, vertebral arteries and accessory nerves.

The basilar part of the occipital bone grows together with the body of the sphenoid bone by the age of 18-20. The layer between them from cartilaginous becomes bone (synchondrosis turns into synostosis). The upper surface of the basilar part of the occipital bone faces the cranial cavity and has a flat area, which, together with the sphenoid bone, forms stingray, where the parts of the brain stem are located.

The lateral parts of the occipital bone from behind pass into the occipital scales. They have on their lower surface occipital condyles elliptical in shape, connecting with the Atlantean. Passes through the condyles the hypoglossal nerve canal. On their lateral edge is the jugular notch, which forms with the same notch of the temporal bone jugular foramen through which the nerves (vagus, glossopharyngeal and accessory) and the internal jugular vein pass. There is a groove on the upper surface of the lateral parts of the occipital bone sigmoid sinus, where the sigmoid venous sinus is located. The occipital scales look like a wide, convex back and downward plate, on the outer surface of which there is external occipital protuberance, and above and below it are the nuchal lines for the attachment of muscles.

On the inner surface of the scales of the occipital bone is internal occipital protuberance. It divides the entire inner surface of the scales into four depressions, of which the lower two correspond to the position of the cerebellar hemispheres, and the occipital lobes of the cerebellar hemispheres are adjacent to the upper two. Up from the internal occipital protuberance there is an unpaired groove of the superior sagittal sinus, and to the sides - the grooves of the transverse sinus, where the venous sinuses of the dura mater of the brain of the same name are located.

Sphenoid bone(os sphenoidale) is located between the occipital and frontal bones at the base of the skull, resembling a butterfly in shape. The sphenoid bone consists of a body and three pairs of processes. To the sides and upward move away small wings, laterally to the sides - big wings, way down - pterygoid processes.

The body of the sphenoid bone is cuboid. It contains the airway that communicates with the front of the nasal cavity. There is a depression on the upper surface of the sinus - Turkish saddle, where the endocrine gland is located - the pituitary gland.

The Turkish saddle has grooves on the sides, in which the internal carotid arteries lie. At the base of each of the small wings is located visual channel. The optic nerve and the ophthalmic artery pass through it into the eye socket. The large wings of the sphenoid bone are turned by one, concave, surface into the cranial cavity, the other, flat, into the cavity of the orbit, and the third, somewhat concave, outward, into the temporal fossa, the bottom of which they make up. There are holes at the base of the large wings: round(for the passage of the II branch of the trigeminal nerve), oval(for the passage of the I I I branch) and spinous(for the passage of the middle artery of the dura mater).

The lower surface of the large wings faces the infratemporal fossa. Between the large and small wings is upper orbital fissure, through which the oculomotor, block, orbital, abducens and optic veins pass.

The pterygoid processes of the sphenoid bone run vertically downward from its body. Each of them has a medial and lateral plate; medial below

ends with a small crochet.

Frontal bone(os frontale) participates in the formation of the roof and base of the skull. It is divided into four parts: frontal scales upward, 2 orbital parts, located horizontally, and bow part, lying between the orbital parts.

The frontal scales with their outer surface are facing forward, and the inner ones - into the cranial cavity. The outer surface is smooth, below it has a sharp supraocular edge, above which there are elevations on the right and left - superciliary arches. Above the brow ridges are the frontal tubercles, and between the brow ridges there is a depression, glabella.

On the inner surface of the frontal scales, along the midline, there is a groove of the superior sagittal sinus next to the grooves corresponding to the cerebral gyri. Lateral, temporal, the surface of the frontal scales is connected below with the large wings of the sphenoid bone, and behind and above with the parietal bones.

The orbital parts of the frontal bone are thin plates, the lower surface of which faces the orbit and forms its upper wall, and the upper surface into the cranial cavity. On the lateral part of the orbital part there is a depression - the fossa of the lacrimal gland. A lattice notch is located between the orbital plates.

The nasal part of the frontal bone closes in front of the ethmoid notch. The nose has two openings leading to the frontal sinus.

Ethmoid bone(os ethmoidaie) is similar in shape to a flattened cube from the sides. lies deep in the skull and takes part in the formation of the walls of the nasal cavity and eye sockets. This bone is light and fragile. It consists of two plates - lattice and perpendicular- and lattice labyrinth.

The lattice plate is located horizontally in the lattice notch of the frontal

bones. It has a large number of holes, and in the median plane, an upwardly facing bony protrusion departs from it, cockscomb, to which the process of the dura mater is attached. Through the holes of the lattice plate pass from

nasal cavity into the cranial cavity olfactory nerves.

The perpendicular plate of the ethmoid bone is located in the median plane and extends vertically downward from the ethmoid plate, taking part in the formation of the nasal septum.

The right and left lattice labyrinths are built of thin plates that run in different directions, forming the walls of the lattice cells containing air and communicating with the nasal cavity. The cells from the side of the nasal cavity are closed by curved bone plates, the upper and middle turbinates, between which the upper nasal passage is located.

On the lateral side, the ethmoid bone has a thin plate (orbital) that makes up the medial wall of the orbit.

Parietal bone(os parietale) -paired. It forms the central part of the cranial vault and is a quadrangular plate, convex on the outside and concave on the inside. There is an elevation on its convex surface - parietal tubercle, easily felt under the skin. Laterally and below the tubercle, there is a rough temporal line, which serves as one of the sites of the beginning of the temporal muscle. The inner concave surface of the parietal bone faces the cranial cavity, has arterial grooves, digital depressions, as well as a groove of the superior sagittal sinus along its sagittal edge. These sagittal grooves of both parietal bones, complementing each other, form one common groove, which serves as the location of the superior sagittal sinus of the dura mater.

Temporal bone(os temporale) is a steam room. She takes part in the formation of the base of the skull and partly of its roof. This is the most complex of the bones of the skull, is a receptacle for the organ of hearing and balance, vessels and nerves pass through its channels, and forms a joint with the lower jaw. Consists of three parts: pyramids(rocky part), drum and scaly. At 3-7 years of age, these parts are completely fused.

Stony part has the shape of a three-sided pyramid, to which the mastoid process of the bone joins behind. This part is turned with its lower surface downward, towards the outer base of the skull, and the front and back - into the cranial cavity.

On the front surface of the pyramid, at its apex, there is a trigeminal impression. The anterior surface takes part in the formation of the roof of the tympanic cavity, being one of the walls of the middle ear.

On the back of the rocky part there is internal auditory opening, through which the facial and vestibular cochlear nerves pass. It leads to internal auditory canal.

On the lower surface of the rocky part there is external sleepy opening, through which the internal von artery enters the channel of the same name. At the apex of the stony part, respectively, the anterior end of the carotid canal is internal sleepy opening; here the internal carotid artery enters the cranial cavity. On the lower surface of the stony part, at the posterior edge of its base, is located jugular fossa. Behind and outside of her is styloid the hole through which the facial nerve exits the skull. In front of this hole is styloid process.

At the apex of the petrous part of the temporal bone, in addition to the carotid canal, opens muscular-tubal canal, which contains the auditory tube and the muscle that strains the eardrum. Through the stony part of the temporal bone also passes facial canal, where the facial nerve is located. This canal begins deep in the internal auditory canal and ends in the styloid foramen. The stony part of the temporal bone includes mastoid, located behind the external auditory canal and easily palpable under the skin. It serves as the site of attachment of the sternocleidomastoid muscle and contains air cells. On its inner surface there is a mastoid notch, from which the digastric muscle originates, and a wide sigmoid sinus groove, which is a continuation of the eponymous groove of the occipital bone and the location of the sigmoid sinus of the dura mater.

Scaly part the temporal bone has the form of a semicircular, vertically located plate, which takes part in the formation of the skull roof. Its inner surface is turned into the cranial cavity, and its outer surface is the bottom of the temporal fossa. Departs from her zygomatic process, forming, together with the temporal process of the zygomatic bone, easily palpable under the skin zygomatic arch. At the base of this process on the temporal bone is located mandibular fossa, serving for articulation with the head of the lower jaw. An articular tubercle is located in front of the fossa.

Drum part The temporal bone is a curved plate that limits the external auditory canal from below and in front.

20656 0

The bones of the skull are connected to each other mainly by means of continuous connections: syndesmoses and, to a lesser extent, synchondrosis. The discontinuous connection is only the temporomandibular joint (except for the joints of the auditory ossicles).

With the help of a scaly suture (sutura squamosa), the scales of the temporal bone are connected with the parietal and large wing of the sphenoid bone. The bones of the facial skull are connected by means of flat harmonic sutures (sutura plana). The specific names of the sutures are made up of the names of the connecting bones, for example: sutura frontozygomatica, sutura frontoethmoidalis, etc. In the skull of the fetus, newborn and child of the first two years of life, in addition to flat sutures, there are fontanelles. The largest of them is the anterior (frontal) fontanelle (fonticulus anterior (frontalis)), it is located between the two parts of the frontal bone and the parietal bones. It has a diamond shape and is overgrown in the 2nd year of life. The posterior (occipital) fontanelle (fonticulus posterior (occipitalis)) is located between the two parietal bones and the occipital, it has a triangular shape, overgrows in the 2nd month of life. Anterior and posterior fontanelles are unpaired. In addition to them, there are paired fontanelles: wedge-shaped (fonticulus sphenoidalis), mastoid (fonticulus mastoideus). Serrated sutures are subsequently formed in place of the fontanelles.

Cartilaginous joints (synchondrosis) are characteristic of the bones of the base of the skull. They are represented by fibrous cartilage. In children, temporary synchondrosis between the body of the sphenoid bone and the main part of the occipital bone (synchondrosis sphenooccipital) is clearly expressed. There are also permanent synchondrosis (between the pyramid of the temporal bone and the main part of the occipital bone, between the large wing of the sphenoid bone and the pyramid of the temporal bone) and cartilage covering the laceration. Usually, with age, a person has a replacement of cartilage with bone tissue. The temporomandibular joint (articulatio temporomandibularis) is a combined condylar joint. It is formed by the head of the lower jaw, the mandibular fossa and the articular tubercle of the temporal bone. The head of the lower jaw approaches the condyle in shape and is covered with cartilage mainly in front.

Fibrous cartilage lines the mandibular fossa only in front of the petrotympanic fissure and the entire articular tubercle.

Temporomandibular joint: 1 - joint capsule; 2 - glenoid fossa; 3 - articular disc; 4 - articular tubercle; 5 - lower jaw; 6 - styloidmandibular ligament; 7 - subulate process; 8 - the head of the lower jaw

A feature of the temporomandibular joint is the presence of an articular disc, which ensures the congruence of the articular surfaces. The disc has the shape of a biconcave lens. The joint capsule on the temporal bone is attached anteriorly to the articular tubercle, and posteriorly at the level of the petrotympanic fissure. On the lower jaw, the capsule is attached to the condylar process in the cervical region (0.5 cm higher in front than in the back). In its anterior section, the capsule is thinner, from the inside along the entire surface it is fused with the articular disc, as a result of which the joint cavity is divided into upper and lower isolated floors. In the lower floor, the synovial membrane covers not only the joint capsule, but also the posterior surface of the neck of the condylar process, which is inside the capsule. At the top floor, the synovial membrane lines the inner surface of the capsule and attaches along the edge of the articular cartilage.

On the lateral side, the joint capsule is strengthened by the lateral ligament. It starts from the base of the zygomatic process of the temporal bone, then fan-shaped backward and downward and is attached to the posterolateral surface of the neck of the condylar process. This ligament limits the posterior displacement of the lower jaw. The joint is also strengthened by the mandibular sphenoid ligament and the mandibular styloid ligament. The first ligament starts from the spine of the sphenoid bone and attaches to the tongue of the lower jaw, and the second spreads from the styloid process to the inner surface of the lower edge of the branch of the lower jaw. The following types of movements are possible in the temporomandibular joint: around the frontal axis - lowering and raising the lower jaw; moving the frontal axis forward - moving the lower jaw forward and backward; around the vertical axis - rotation.

When lowering the lower jaw, the chin protrusion is described. The bones of the skull are interconnected mainly by means of continuous connections: syndesmosis and, to a lesser extent, synchondrosis. The only discontinuous connection is the temporomandibular joint (except for the joints of the auditory ossicles).

In an adult, syndesmosis of the skull is represented by sutures. Sutures connect the bones of the roof of the cerebral skull, as well as the bones of the face. There are jagged and scaly seams between the bones of the roof. The serrated suture (sutura serrata) is between the parietal bones (sagittal suture); between the parietal and frontal (coronal suture); between the parietal and occipital (lambdoid suture).

Diseases of the joints V.I. Mazurov

Everyone will agree that the head of each person plays no less important function in his life than the heart. In fact, the human skull is a complex system that has a very interesting structure and performs serious functions. The bones of the head protect the brain and the senses. They are joined together by seams and provide support for the digestive and respiratory systems.

The skull is divided into the facial and brain regions. The bones of the cerebral part form a cavity for the brain and partly for the sensory organs. In addition, they serve as the basis of the face and skeleton of the initial sections of the digestive and respiratory systems. Some cranial bones have cavities that are filled with air. They are connected to the nasal cavity. Due to this structure of bones, the mass of the skull is not very large, but at the same time, its strength does not decrease from this. The cerebral skull consists of eight bones: two temporal, two parietal, frontal, sphenoid, ethmoid and occipital bones. Some bones of the facial part of the skull serve as the basis for the skeleton of the chewing apparatus. Other bones are smaller in size and make up the facial cranial cavity. Let's consider the anatomy of these two departments in more detail.

Bones of the cerebral cranial region

So, the brain section consists of eight bones:

frontal;
occipital;
wedge-shaped;
lattice;
two temporal;
two parietal.

The upper part of the cerebral skull is called its vault, in other words, the roof. The lower part is its base. Between the fornix and the base there is a conditional line passing through the occipital external protrusion, along the nuchal superior line to the base of the mastoid process. Then the line continues above the auditory external opening, along the base of the process of the zygomatic type and along the crest of the infratemporal view of the main wing of the sphenoid bone. The line reaches the nasolabial suture along the infraorbital margin.

The anatomy of the cranial vault involves its division into several bones. In shape, it is half an ellipsoid. Its long axis is directed to the frontal-occipital part. It corresponds to the longitudinal diameter of the brain box. Two more axes run vertically and transversely. The vault of the skull has morpho-functional areas:

unpaired fronto-parieto-occipital region;
paired temporal region.

They are separated by temporal lines and differ in relief, mechanical conditions, and bone structure. The bones of the arch have a three-layer structure. There are inner and outer compact plates, which have between themselves a diploe, that is, a spongy substance. In different areas of the vault, the ratio of compact plates and the thickness of the diploe differs. It all depends on individual variability.

It has been proven that the diploe is well developed in the parasagittal zone, where the outer plate is thicker than the inner one. The lateral sections of the arch have the opposite relationship. There is less diploe in the temporal parts.

The structural features of bones determine their strength. There have been studies that have shown that the compression strength of the occipital and parietal bone is greater than that of the frontal bone. The inner lamina is more fragile. Even if there is no external damage, a comminuted fracture of such a plate may occur. This gave reason to call it a vitreous plate.

In the anatomy of the bones of the cerebral skull, the spongy substance of the bones is of great importance. The diploic canals are located there. They contain diploic veins. The following important diploic canals are distinguished in the cranial vault:

frontal;
front;
posterior temporal;
occipital

The diploic canals are functionally classified. In this regard, it is possible to distinguish outgoing, depositing and communicating channels. They pass through the suture lines in the cranial base. They are able to split into several branches. In the outer part of the skull, the relief individually varies depending on age and gender.

The inner skull has a more complex relief. Cerebral eminences and finger-like depressions can be expressed to varying degrees. Arterial grooves, branching tree-like, originate in the cranial base from the spinous foramen. The meningeal middle artery passes through it. In the structure of the inner cranial surface, granulation dimples can be seen. They are highly volatile. In small dimples there are single growths of the arachnoid meninges. These growths accumulate in large dimples.

The base of the skull also has two surfaces - an inner and an outer one. The inner surface, as in the case of the cranial vault, reflects the shape of the head. It has depressions and elevations. Three pits are distinguished from localization.

The anterior fossa is the bed of the frontal lobes of the cerebral hemispheres. It is formed by the orbital parts of the frontal bone, part of the body of the sphenoid bone, the ethmoid plate and the upper surface of the lesser wings. In the middle of the wedge-shaped protrusion, there is a border between the middle and anterior fossa.
Middle fossa. It is formed by the body of the sphenoid bone, the anterior surface of the hard stony part of the temporal region, small and large wings and the lower region of the scales of the temporal bone. In the middle fossa there are lateral and middle sections. In the lateral sections, the temporal lobes of the hemispheres are located.
Posterior fossa. It is mainly formed by the occipital bone. However, the body of the sphenoid bone and the stony parts of the temporal bone take part in this. The posterior fossa contains the cerebellum and the brain stem.

There are three sections at the outer base of the skull.

The anterior section is connected to the facial bones. It forms the nasal cavities and the roof of the eye sockets.
Middle department. It originates at the base of the pterygoid processes and extends to a line that extends through the mastoid processes, as well as the anterior edge of the main foramen.
Back section. It is formed by the temporal and occipital bones. Has three areas - mastoid, nuchal and occipitotemporal.

There are many small and large arteries at the base of the skull. Blood and cranial nerves pass through them. The thickness of the bone is not the same in different places. The structure of the stronger sections is a system of longitudinal beams converging to the body of the wedge-shaped bone. They are held together by crossbars running transversely to the boundaries between the fossae of the skull. The depressions of the cranial fossa are fragile. This is where fractures often occur, because the bone is quite thin. In the anterior fossa, injuries form, affecting the ethmoid plate. In the middle fossa, fractures pass transversely through the back of the region, which is called the Turkish saddle. In the posterior fossa, fractures affect the holes, and the apex of the pyramid breaks off.

The Turkish saddle is located at the center of the inner base of the skull. In front, it is bounded by the tubercle of the saddle. The inclined anterior processes hang over it. At the back it is limited by the back of the saddle. There is a pituitary fossa in the center of the saddle. It is a receptacle for the pituitary gland, that is, the endocrine gland.

Features of the cranial structure

Of course, the structure of the entire skull is amazing, however, the main feature of the anatomy of the skull is pneumatic bones containing cells or airways. Most of these sinuses communicate with the nasal cavity and play the role of paranasal cavities. Their role is very important - they act aerodynamically on the inhaled air, so the air stream comes into contact with the olfactory receptors, which are located in the mucous membrane of the nasal cavity, more precisely, in its upper part. The paranasal sinuses often undergo pathological processes leading to intracranial complications such as brain abscess and meningitis.

There are five main parts.

Frontal sinus. This is a paired cavity, which is divided by a septum. Also in this part is the middle nasal passage. The sinus washes to be located in different places, since its length varies, - in the brow ridges, frontal scales and the orbital part of the frontal type bone. There are unicameral and multi-chambered sinuses.
Sphenoid sinus. Its location is the body of the sphenoid bone. There may be additional septa in the sinus.
Lattice cells. Their opening occurs in the middle and upper nasal passages.
Mastoid cells. Their communication with the tympanic cavity occurs through the mastoid cave. Cells may vary in size. There are diploic, compact, mixed and pneumatic mastoid processes.
Maxillary sinus. This is the largest accessory cavity of the nose.

The structure of the facial cranial region

The structure of the facial region is associated with the development of the jaws, nasal cavity, digestive and respiratory systems. An imprint on this department is imposed by the speech function. Some features of the anatomy of the lower jaw are associated with the muscles that are involved in speech. The facial skull includes three main divisions.

Orbital-temporal region. These are the orbit, the anterior recess of the temporal fossa, the anterior cranial middle fossa, the pterygo-palatine and infratemporal fossa.
Nasal section. These are the paranasal sinuses, the nasal cavity and the nose itself.
Jaw region - zygomatic bones, lower and upper jaws.

The upper jaw is an important part of the face and nasal cavity. In different parts of the jaw, there is an unequal ratio of spongy and compact matter. The alveolar process has a thick layer of spongy substance, from where it passes into the following processes. The frontal process has very small cells of the spongy substance. The spongy substance from the zygomatic process is directed to the infraorbital margin, from where it spreads almost to the frontal process. The spongy beams of the jaw are generally located at different angles. They are grouped into the lateral and medial systems.

The lower jaw is the solid base of the lower facial region. It is she who largely determines the facial shape. Signs of the lower jaw are a decrease in its massiveness, an increase in the angle of the branch, the presence of a chin spine, and so on. The lower jaw is the only movable part of the facial skeleton. Many muscles are attached to it, especially the chewing muscles, because the configuration depends on them. The lower jaw is characterized by a basal arch. The canal, in which the nerves and blood vessels pass, is removed from the dental roots, but there are exceptions. The chin hole is the exit from the jaw canal. It may be absent on one side, sometimes on both sides. There can be additional holes on one side. The ratio of spongy and compact matter is also not the same in different parts of the jaw. The outer compact lamina is thicker than the inner one.

There is also a temporomandibular joint. It is formed by the articular surfaces of the jaw head, as well as by the mandibular fossa of the temporal-type bone. These surfaces are covered with fibrous cartilage. There is an articular disc, with the help of which the joint cavity is divided into lower and upper compartments. It grows together with the joint capsule.

This is a quick tour of the anatomy of the human skull. As we could see, the head is a complex system made up of different bones, joints, and other elements. Everything is very interconnected, therefore, if one part of the skull suffers, this affects not only its entire condition, but also the entire body. Therefore, let's protect our head from all kinds of injuries!

The vault, or roof of the skull, is the upper part of the skull that surrounds and protects the brain.

The vault is formed by four bones: the frontal, two parietal and part of the occipital. These bones are formed in a process in which the original soft membrane of connective tissue ossifies (hardens) and forms bone tissue, bypassing the intermediate stage of cartilage, as is the case with other bones of the skull. Of particular interest are the following details of the cranial vault:

Sagittal suture running along the midline of the fornix from the lambdoid suture in the back to the coronal suture.
The crown (crown) is the central, uppermost part of the skull along the sagittal suture.
The space between the two parietal tubercles is the widest part of the skull.
A sophisticated suture system that allows hard bones to grow during formation and to ensure the strength and stability of the adult's skull.

Base of skull

This is an unusual view of the skull from below, allowing you to see the upper jaw and the opening through which the spinal cord passes.

The bones located in the middle part of the base of the skull (ethmoid, wedge-shaped and part of the occipital) are formed differently than the bones of the cranial vault. They develop from early cartilage structures in a process called endochondral ossification (ossification). The upper jaw consists of two teeth bearing bones, one on each side. The palatine processes of the upper jaw and the horizontal plate of the palatine bone form the hard palate.

Sky defects

When the structures of the palate do not connect normally before birth, a cleft palate forms, that is, the gap between the mouth and nasal cavity. If the gap passes through the upper jaw, it becomes visible on the upper lip ("cleft lip"). However, surgeons can often correct this defect.

For children with a narrow palate and displaced teeth, an orthodontic device can be inserted, which will gradually push the palatine processes to the sides of the longitudinal midline, putting pressure on it.

Over the course of several months, the edges of the suture are stretched to the sides, allowing new bone to grow and giving additional space for the teeth.

Skull defects

The way the skull develops is the ears are hot - the growing brain forces the bones to move apart in the seams, so any defect in the bones or seams themselves can lead to strong changes in the shape of the child's head and its appearance.
Isolated premature suture fusion (when individual joints are fixed and closed before the brain reaches its final size) is called craniostenosis. This significantly reduces the ability of the seams to grow in normal directions.

However, the brain continues to grow in all possible directions, causing the skull to take on an abnormal shape. Depending on which seams are damaged, the following deformations differ:

scaphocephaly Elongated, boat-like skull resulting from stenosis (premature closure) of the sagittal suture
brachycephaly- a noticeably pointed short skull, formed as a result of bilateral stenosis of the coronal suture;
plagiocephaly, in which the head has a "twisted" version of asymmetric deformity, formed as a result of stenosis of one half of the coronary suture;
oxycephaly- an abnormally high oblique skull, usually a consequence of the early fusion of the sagittal and coronary sutures.

Disorders in bone formation can also cause deformation of the skull. With achondroplasia (dwarfism), cartilaginous bones are affected. This leads to the fact that the bones of the base of the skull are shortened, while the bones of the vault are normal (membrane bones are not affected). Hydrocephalus (dropsy of the brain) is a serious condition associated with increased formation of cerebrospinal fluid surrounding the brain. The skull expands excessively due to the pressure of the fluid accumulated in its cavity.

Foramines - channels in the skull

Foramina - from the Latin word foramen meaning "hole". These openings are many channels in the skull bones that allow blood vessels and 24 cranial nerves (12 pairs on each side) to enter and exit the skull.

Other small and less regular tubules are anastomoses connecting the external veins of the skull with the internal ones. They are called emissary veins, and the outlets for them are emissary holes. These can spread an infection from the outside of the skull, causing a more severe infection inside. The most important holes:

the foramen magnum, through which the spinal cord connects to the brain stem;
laceration between the pyramidal part of the temporal bone and the ethmoid bone;
oval opening (on one side) for the mandibular branch of the trigeminal nerve;
the spinous foramen allows the middle meningeal artery to pass inside the cranium;
styloid foramen for the passage of the seventh cranial nerve;
jugular foramen for sigmoid sinus, inferior petrosal sinus and three cranial nerves;
the carotid canal for the passage of the carotid artery (the main artery of the neck) and associated nerve fibers.

1. General information about osteology

Skeleton (skeleton) - the totality of all the bones of the human body. There are more than 200 bones in the human body.

Human skeleton:

1) performs a supporting function, supporting a variety of soft tissues;

2) protects internal organs by creating containers for them;

3) is a depot organ of many important microelements (calcium, phosphorus, magnesium).

The bone (os) is covered on the outside by the periosteum (periosteum), inside the bone there is a medullary cavity (cavitas medullares), in which the red and yellow marrow is located (medulla ossium rubra et flava).

Bone is 29% organic, 21% inorganic and 50% water.

Bone classification:

1) tubular bones (os longum). Most often they have a triangular or cylindrical shape. The length of the bone can be divided into about three parts. The central part, which makes up most of the length of the bone, is the diaphysis, or the body of the bone, and the epiphysis (epiphysis) are the marginal parts that have a thickened shape. The epiphyses have an articular surface)