The structure of the skeleton. Anatomical structure of the spine, features of various departments

What parts does the skeleton consist of?

What are the functions of the skeleton?

Skeleton of the head, torso, upper and lower limbs.

Support, protective.

1. What are the features of the bones of the skull.

The skull protects the brain and sense organs from various injuries. The bones of the skull are flat, strong, they are connected to each other by sutures. A suture is a strong, immovable connection of bones.

2. Name the only movable bone of the skull and indicate how it connects to it.

Only one bone lower jaw- movably connected with the rest of the bones. This allows us not only to grab and chew food, but also to talk.

3. How is the human skull different from the chimpanzee skull?

Humans, unlike mammals, have better developed brain department associated with an increase in brain volume.

4. List the bones related to the brain and facial parts of the skull.

The cerebral region of the skull consists of the frontal, occipital, two parietal and two temporal bones. The facial region includes various large and small bones, including paired zygomatic and nasal bones, unpaired maxillary and mandibular bones. On the jaws there are cells for teeth. In the lower part of the skull there are several small holes and one large one - a large occipital foramen. Through a large occipital foramen, the brain is connected to the spinal cord, and blood vessels pass through small holes.

5. Why are the cervical vertebrae less massive than the lumbar ones?

The more stress the vertebrae experience, the more massive they are. Therefore, the lumbar vertebrae are much larger than the cervical ones.

6. What is the structure of a vertebra and what role do cartilaginous intervertebral discs play?

Each vertebra consists of a massive part - a body and an arch with several processes. The vertebrae are located one above the other so that their openings coincide, and a vertebral capal is formed, in which spinal cord. The spine protects the delicate spinal cord from injury. Between the vertebrae are the intervertebral cartilage discs. Thanks to them, a semi-movable connection is formed. Cartilage is elastic and can stretch and harden. When we sleep, its thickness increases, and when we walk, it decreases. As a result, a person is taller in the morning than in the evening.

7. What bones belong to the chest? Why are the ribs connected to the sternum in a semi-movable way?

The chest is located in the upper part of the body. It is formed by the sternum ( middle part anterior chest wall), 12 pairs of ribs and thoracic spine. The chest protects the heart and lungs located in it from damage. Ten pairs of ribs are mobile (joints) connected to the vertebrae and semi-mobile (cartilages) to the sternum. The two lower pairs of ribs are not connected to the sternum (they are articulated only with the vertebrae). This allows all the ribs to rise and move apart when inhaling, which increases the volume. chest cavity and ensures the flow of air into the lungs, and when exhaling, it descends and pushes the air out of them

The spine is a universal multifunctional natural invention. He is biological mechanism, a rod or axis of support for the body, providing it with the necessary stability and enabling dynamic activity. Without a spine, a person will lose the ability to change body position and movement.

At the center of this rod is spinal canal filled with spinal cord. Inside the canal there are restrictions in the form of vertebral arches and ligaments. The curves and sectors of the human spine have certain functions. There are 31 pairs of intervertebral foramens in the canal. Nerves and their endings pass through these openings.

The structure of the spine and its functions

The components of the spine, in addition to all the vertebrae interconnected, is the region of the coccyx and sacrum, fastened through cartilage and ligaments. The anatomy of the spine is quite simple. It consists of 31-37 vertebrae, their number varies depending on the number of vertebrae in the coccyx region. The length of the spine in young age a few more. For example, in boys, its length ranges from 72 to 76 cm, and in girls from 68 to 71 cm. With age, the spine shortens by about 4-8 cm. This shortening occurs as a result of atrophy of the discs located between the vertebrae.

The main functions of the spine:

• motor;
• depreciation;
• support;
• protective.

The entire skeleton is attached to the spine (limbs, skull, hip joint and rib cage). He is responsible for correct location all internal organs. All vertebrae are interconnected through:

• ligaments;
• tendons;
• facet joints;
• intervertebral discs.

The functions of the spine are distributed in such a way that each connecting element has its own purpose.

1. Ligaments are designed to connect the vertebrae.
2. The tendons attach the paravertebral muscles to the spine.
3. The mobility of the vertebrae is provided by the facet joints.
4. Depreciation and load adjustment is carried out by means of intervertebral discs.

The condition of the discs and vertebrae affects the health and strength of the entire spinal system. In the event of their deformation, diseases of the ligaments, tendons and muscles may occur, with big risk occurrence of diseases of the musculoskeletal corset.

Division of the spine into zones

The spine has the following sections:

• coccygeal;
• sacral;
• lumbar;
• chest;
• cervical.

There is a single classification of the vertebrae, with each department designated by a Latin character. In each section, the vertebrae are numbered sequentially.

cervical The spine is made up of seven vertebrae, numbered from C1 to C7. Occipital part The skull is considered a zero vertebra.

AT thoracic region 12 vertebrae, numbered from T1 to T12.

AT lumbar 5 vertebrae, numbered L1 to L5.

Vertebrae sacral department received the Latin letter S, there are only 5 of them. They are numbered from S1 to S5.

The coccyx section is considered the most unstable, the number of vertebrae in it is different people may differ and vary from 3 to 5. They are numbered Co1 - Co5.

The structure of the various parts of the spine

Depending on the purpose and functionality, each section of the spine has its own structure and structural features.

The cervical spine has the greatest mobility. It is achieved due to the unique structure of the first two vertebrae, which are responsible for the ability to turn the head in different directions. Since the force during turns is minimal, these vertebrae themselves are narrow and have small bodies. This part of the spine is often diagnosed intervertebral hernia or osteochondrosis.

The largest in size is the thoracic region. It is less mobile than other sectors. It includes many organs, including the attachment of ribs to it. For this reason, the vertebrae of this department are more massive and have big bodies. Since this department is little involved in the movement, the formation of hernias in it is a very rare occurrence.

The most huge pressure falls on the lumbar region, which is also reflected in the size of the vertebrae of this segment. Here the vertebrae have the largest diameter and height.

The sacral segment has unique features structures due to the fact that all its vertebrae are a single whole. They have fused into a single structure, with the largest being the first 2 vertebrae of this sector, followed by the vertebrae somewhat smaller in size. In the vertebrae of this segment are often observed:

• sacralization;
• lumbarization.

Sacralization is a phenomenon that implies the fusion of the 5th lumbar vertebra with the 1st sacral. Lumbarization is the separation of the 1st and 2nd sacral vertebrae. These processes are not considered pathological.

When a pathology occurs, both of the most vulnerable departments usually suffer: the sacral and lumbar, since when the lower back is bent most of load falls on these two departments.

Physiological features of the spine and their role

Lateral projection of the spine allows you to see a picture in which the spine looks like a single whole. The physiological curves of the human spine are very harmoniously combined with the entire structure of his skeleton. In this case, the spine is not a straight line, but looks like a guitar, with smooth transitions from one segment to another. Its curvature is smooth and thanks to it there is a softening of the load on individual vertebral zones. This useful curvature is like a spring, and can, under certain loads, either compress or stretch.

The curves of the spinal column look like a dollar sign or English letter S. The curve protruding forward is called lordosis, and backward is called kyphosis. Such a structure is noted in an adult, while infants still lack lordosis and kyphosis, and the spine looks somewhat different. Bends in various vertebral zones have different direction. For example, the curvature of the cervical and lumbar regions has a forward direction, therefore, they are respectively called the lordosis of the corresponding sector. But the formation of the curves of the spine of the thoracic region is directed backward, therefore, there is a thoracic kyphosis.

Thanks to the curves of the spinal column, he is able to courageously withstand a huge load, which is almost 20 times higher than the load of a concrete column of similar dimensions.

If the function of the spine is impaired and there is any pathology, when there is an excessive increase in the bends, or their smoothing, then in such cases scoliosis or osteochondrosis is often diagnosed.

On the spine of an adult there are 4 bends, thanks to which it is supported correct posture. Thanks to lordosis and kyphosis, the elasticity of the spinal column is maintained and during physical activity there is a uniform distribution of the entire load on each of the departments. If compared with a concrete pillar, then it cannot adequately respond to an aggressive impact. external factors and breaks down over time.

At various circumstances the functions of the spine are modified, while its bends can become clearly painful and distorted pathological forms. In this case, the back may become stooped, the chest may become flatter, and the shoulders may be lowered. Such outlines of the spine indicate kyphosis of the thoracic region. If such a pathology occurs at a young age, we can talk about the manifestation of the disease.

At first, the stoop looks cosmetic defect, but after a while there are back pains that tend to increase. In this case, there is compression of the intervertebral discs and deformation of the bodies of the vertebrae themselves.

AT old age with weakening muscle tone this condition can be called conditionally normal, but if such a condition of the spine is observed in a teenager, then it is necessary to sound the alarm so as not to miss the time to eliminate negative factors.

Question 1. What is the structure and purpose of the skull?

The skull consists mainly of flat, motionless bones connected to each other. The only movable bone of the skull is the lower jaw. The skull protects the brain and sense organs from external damage, provides support for the muscles of the face and primary departments digestive and respiratory systems.

In the skull, a large brain and a smaller facial section are distinguished. The medulla of the skull is formed following bones: unpaired - frontal, occipital, wedge-shaped, ethmoid and paired - parietal and temporal. The largest bones facial department- paired zygomatic, maxillary, as well as nasal and lacrimal bones, unpaired - the lower jaw and the hyoid bone located on the neck.

Question 2. Why are the bones of the skull connected motionless?

Because the skull protects the brain and sensory organs from external damage. And if the bones of the skull are movably connected, then the brain and sense organs will not be fully protected.

Question 3. What bones form the cerebral part of the skull?

The brain part of the skull is formed by the following bones: unpaired - frontal, occipital, sphenoid, ethmoid and paired - parietal and temporal.

Question 4. What role do spinal curvatures play?

The human spine has curves that play the role of a shock absorber: thanks to them, shocks are softened when walking, running, jumping, which is very important for protecting internal organs and especially the brain from concussions.

Question 5. What departments does the limb skeleton consist of?

The skeleton of any limb consists of two parts: the girdle of the limbs and the skeleton of the free limb. The bones of the limb girdle connect free limbs with the skeleton of the body.

Question 6. What bones form the skeleton of the belt upper limbs?

The girdle of the upper limbs is formed by two shoulder blades and two collarbones.

Question 7. What is the structure of the hand?

Brush formed large quantity small bones. It distinguishes three sections: the wrist, metacarpus and phalanges of the fingers.

Question 8. How is the structure of the lower leg and forearm similar?

The lower leg and forearm are formed by two bones. The bones of the lower leg include the tibia and fibula. The forearm is formed by the radius and ulna.

Question 9. What is a bony pelvis?

The bony pelvis is the two pelvic bones that connect to the sacrum. The pelvic bones together with the sacrum form a ring on which the spinal column (torso) rests.

Question 10. What departments does the skeleton of the free lower limb?

The skeleton of the free lower limb consists of the femur, lower leg and foot bones.

THINK

1. In connection with what does a person have curves of the spine?

The spine has four bends, as a result of which its profile contour forms a wavy line. The bends facing forward with a bulge are called lordosis, and those turned with a bulge back are called kyphosis. There are cervical and lumbar lordosis, and thoracic and sacral kyphosis. The natural curves of the spine act like a spring. Due to these bends, elastic deformations occur in the spine (in response to the action of gravity) and wave shocks during walking or running.

Both kyphosis and lordosis are physiological phenomena. They are associated with vertical position human body (upright posture).

2. How does the human skeleton differ from the skeleton of mammals?

In mammals, the spine is divided into five sections: cervical, thoracic, lumbar, sacral, and caudal. Only cetaceans do not have a sacrum. The cervical region almost always consists of seven vertebrae. Thoracic - from 10-24, lumbar from 2-9, sacral from 1-9 vertebrae. Only in the caudal region, their number varies greatly: from 4 (in some monkeys and humans) to 46.

Real ribs articulate only with the thoracic vertebrae (rudimentary may be on other vertebrae). They join in the front sternum forming the chest. The shoulder girdle consists of two shoulder blades and two collarbones. Some mammals do not have clavicles (ungulates), in others they are poorly developed or replaced by ligaments (rodents, some carnivores).

The pelvis consists of 3 pairs of bones: iliac, pubic and ischial, which are tightly fused together. Cetaceans do not have a true pelvis.

The forelimbs serve as mammals for movement on the ground, swimming, flight, grasping. Brachial bone greatly shortened. The ulna is less developed than the radius and serves to articulate the hand with the shoulder. The hand of the forelimb consists of the wrist, metacarpus and fingers. The wrist consists of 7 bones arranged in two rows. The number of metacarpus bones corresponds to the number of fingers (no more than five). Thumb consists of two joints, the rest - of three. In cetaceans, the number of joints is increased.

AT hind limbs femur most mammals have shorter legs.

Vertebral displacement is pathological change in the structure of the spinal column. Doctors use the term spondylolisthesis, which comes from the Greek words "spondylo" and "listhesis", which literally mean "vertebra" and "displacement". With spondylolisthesis, there is a displacement of the intervertebral discs, which are the connecting link between the vertebrae.

Brief anatomy

The spine consists of 33-35 vertebrae, which are interconnected by intervertebral joints and together form the spinal column, which performs the supporting function of the body. AT spinal column the spinal cord is responsible for transmission nerve impulses from the brain and signals from receptors to it.

Muscles are attached to almost every vertebra - cervical, trunk muscles, lower back. The vertebrae are also connected to each other by muscles that allow a person to bend and unbend the spine. Displacement of the spine leads to a violation of many functions.

Causes of displacement of the vertebrae

Strong physical exercise directed at the spine, or jerky movements especially with heavy objects. Displacement of the disc occurs due to insufficient muscle strength or weakening of the joints.

Congenital weakness of the spine. Especially dangerous displacement discs of the spine becomes for children, because it leads to further damage to the osteogenesis of the spine. Often in childhood displacement of the thoracic vertebrae occurs.

Age changes. A vertebra, like any bone, is made up of 70% inorganic substances- phosphates and calcium. Happens with age degenerative changes in the bones - the amount of organic matter decreases, the bone becomes brittle. Under load, the vertebrae can easily crumble, which will lead to displacement.

Spondylolisthesis is also a consequence of certain diseases - osteochondrosis, inflammation

Compression fracture of the body of the l1 vertebra

Among the injuries that happen to the human body, compression fractures of the spine are among the most dangerous. Such injuries can leave serious complications that will remind you of yourself throughout your life. The fact is that the spine is the main support of our body, it is based on the skeleton. Without this part, we can neither walk nor stand. In addition, the spine protects the spinal cord, which performs two important features- reflex and conductive.

There are 24 small bones in a vertebra. These vertebrae are located one above the other, so the spinal column is formed. Every two vertebrae have an intervertebral disc between them, that is, a connective tissue flat pad. In addition, the vertebrae are connected by ligaments. There are joints between them. There are five divisions of the spine.

The reasons

To begin with, it should be noted that compression fracture there is a strong compression of the vertebral body, while there is a decrease in its height. This can happen if a person falls forward, which causes pressure on the spine. The person may fall off the chair. In such a situation, he usually protects his head, that is, holds it as high as possible. It turns out that top part the body rises and the person falls on the buttocks. At this point, the blow is directed to the front of the spine.

However, there are a lot of reasons due to which damage to the L1 vertebra occurs. Interestingly, in some cases, a fracture can occur even due to slight pressure on the back. Why? The fact is that some people have a weak bone, and this is observed for some pathological diseases. For healthy person impact force should be much greater. This can be compared with the state of the crossbar, which is intended for the athlete to perform exercises. At pressure

Scoliosis. Symptoms, degrees of scoliosis, diagnosis and treatment. Scoliosis of the thoracic, lumbar. Gymnastics, exercise and massage. Surgery for scoliosis.

The site provides background information. Adequate diagnosis and treatment of the disease is possible under the supervision of a conscientious physician.

Scoliosis- this is a deformation of the spine, in which there is a lateral curvature of the spine with a simultaneous rotation of the vertebral bodies around vertical axis. The disease is most often detected for the first time in childhood. As the child grows, scoliosis usually becomes more pronounced.

Scoliosis is often confused with the term "poor posture". Scoliotic posture - less serious condition, in which there is only a lateral curvature of the spine. With scoliosis, the rotation of the vertebrae is a prerequisite.

In 80% of cases, the origin of scoliosis in a patient remains unidentified - there is a so-called idiopathic scoliosis(see below).

Anatomical features of the spinal column

sacral kyphosis - curvature of the sacrum, similar to thoracic kyphosis (rigidly fixed, since the sacral vertebrae are firmly fused to each other)

Normal physiological curves are supported by the natural configuration of the spinal column, the normal tone of the back muscles.

What is posture?

How it grows and forms

The structure and divisions of the human spine

The human spine, which consists of 32-34 rows of vertebrae and is also called the "vertebral column" is the basis of the entire human skeleton. In this case, the vertebrae are interconnected intervertebral discs, joints and ligaments.

What is the structure of the human spine?

There is a generally accepted division, according to which certain parts of the human spine are distinguished. In addition, each of the departments has a certain number of vertebrae. For convenience, the vertebrae are labeled with Latin letters(in first letters Latin names departments) and numbers that indicate the number of the vertebra in the department. It is also worth remembering that the numbering of the vertebrae is carried out from top to bottom.

human cervical spine (also called cervical part), consists of only 7 vertebrae, with corresponding numbering from C1 to C7. In doing so, it must be taken into account that occipital bone The skull is considered a "null" vertebra and is numbered C0. feature this department is its high mobility;

There are 12 vertebrae in the human thoracic spine, numbered from T1 to T12. At the same time, there are alternative options in which D (D1-D12) and Th (Th1-Th12) are used instead of "T". This department is the most inactive, the loads on it are not so great, but it is he who serves as the main support for the chest;

in the lumbar region there are only 5 vertebrae numbered from L1 to L5. It is this department that is most often the place of appearance various diseases spine simply for the reason that it accounts for maximum load, at the same time it must be sufficiently mobile;

the coccygeal section includes from 3 to 5 vertebrae, numbered from Co1 to Co5, but in adults they fuse into a single coccygeal bone.

Curves allow

Causes, symptoms and treatment of spinal concretion

Concretion of the vertebrae is a pathology characterized by complete or partial fusion of neighboring elements of the spinal column with each other.

The disease develops for many reasons - these may be violations during intrauterine development or the effects of trauma. Previously, concretion was quite rare, about once in several tens of thousands of patients. Now it is more common.

Norm and deviations from the norm

In some cases, bone fusion is normal. This applies, for example, pelvic bones, which grow together with age and become more durable. The concretion of the vertebral bodies (coccygeal, lumbar, cervical) is a pathology.

There is no need to be afraid of this process during the period of growing up, since there is a replacement cartilage tissue on the bone. And this applies to all bones, both the spine and, for example, the skull. In this case, the concretion is considered physiological.

Sometimes pathology is a consequence of hypoplasia or aplasia of the intervertebral tissue. Why it develops is not known for certain.

However, according to doctors, most often the disease is congenital. It also happens that a child receives a “pest” gene from his parents (one or both at once).

Stages of disease development

Partial or complete concretion of the vertebral bodies appears in children at the beginning of genesis. Doctors classify it as a developmental disorder. Depending on the time when the process was discovered, three stages are distinguished:

Sometimes it is possible to detect violations in the development of the spine even on early dates pregnancy, at about 5-7 weeks. At this stage, the discs have already appeared, and the vertebral structures are clearly visible.

The structure and shape of the vertebrae

Vertebral column (columna vertebralis) ( rice. 3, 4 ) - the real basis of the skeleton, the support of the whole organism. The design of the spinal column allows it, while maintaining flexibility and mobility, to withstand the same load that an 18 times thicker concrete column can withstand.

The spinal column is responsible for maintaining posture, serves as a support for tissues and organs, and also takes part in the formation of the walls of the chest cavity, pelvis and abdominal cavity. Each of the vertebrae that make up the spinal column has a through vertebral foramen (foramen vertebrale) inside ( rice. eight). In the spinal column, the vertebral foramina make up the spinal canal (canalis vertebralis) ( rice. 3), containing the spinal cord, which is thus reliably protected from external influences.

In the frontal projection of the spine, two sections are clearly distinguished, differing in wider vertebrae. In general, the mass and size of the vertebrae increase in the direction from the top to the bottom: this is necessary to compensate for the increasing load carried by the lower vertebrae.

In addition to the thickening of the vertebrae, the necessary degree of strength and elasticity of the spine is provided by several of its bends lying in the sagittal plane. Four multidirectional bends, alternating in the spine, are arranged in pairs: the bend facing forward (lordosis) corresponds to the bend facing backward (kyphosis). Thus, cervical (lordosis cervicalis) and lumbar (lordosis lumbalis) lordosis correspond to thoracic (kyphosis thoracalis) and sacral (kyphosis sacralis) kyphosis (Fig. 3). Thanks to this design, the spine works like a spring, distributing the load evenly along its entire length.

How many vertebrae? In total, there are 32–34 vertebrae in the spinal column, separated by intervertebral discs and somewhat differing in their structure.

In the structure of a single vertebra, the vertebral body (corpus vertebrae) and the vertebral arch (arcus vertebrae), which closes the vertebral foramen (foramen vertebrae), are distinguished. On the arch of the vertebrae are processes various shapes and appointments: paired upper and lower articular processes (processus articularis superior and processus articularis inferior), paired transverse (processus transversus) and one spinous (processus spinosus) process, protruding from the arch of the vertebra back. The base of the arc has the so-called vertebral notches (incisura vertebralis) - upper (incisura vertebralis superior) and lower (incisura vertebralis inferior). Intervertebral foramen (foramen intervertebrale), formed by cuts of two adjacent vertebrae, open access to the spinal canal on the left and right ( rice. 3, 5 , 7 , 8 , 9 ).

In accordance with the location and structural features in the spinal column, five types of vertebrae are distinguished: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 3–5 coccygeal ( rice. four).

The cervical vertebra (vertebra cervicalis) differs from others in that it has holes in the transverse processes. The vertebral foramen, formed by the arch of the cervical vertebra, is large, almost triangular in shape. The body of the cervical vertebra (with the exception of the I cervical vertebra, which has no body) is relatively small, oval in shape and elongated in the transverse direction.

At the first cervical vertebra, or atlas (atlas) ( rice. 5), the body is missing; its lateral masses (massae laterales) are connected by two arcs - anterior (arcus anterior) and posterior (arcus posterior). The upper and lower planes of the lateral masses have articular surfaces (upper and lower), through which the 1st cervical vertebra is connected to the skull and the 2nd cervical vertebra, respectively.

In turn, the II cervical vertebra ( rice. 6) is distinguished by the presence on the body of a massive process, the so-called tooth (dens axis), which by origin is part of the body of the first cervical vertebra. The tooth of the II cervical vertebra is the axis around which the head rotates along with the atlas, therefore the II cervical vertebra is called axial (axis).

On the transverse processes of the cervical vertebrae, rudimentary costal processes (processus costalis) can be found, which are especially developed in VI cervical vertebra. The VI cervical vertebra is also called protruding (vertebra prominens), since its spinous process is noticeably longer than that of neighboring vertebrae.

Thoracic vertebra (vertebra thoracica) ( rice. eight) is distinguished by a large, compared with the cervical, body and an almost round vertebral foramen. The thoracic vertebrae have a costal fossa (fovea costalis processus transversus) on their transverse process, which serves to connect with the tubercle of the rib. On the lateral surfaces of the body of the thoracic vertebrae there are also upper (fovea costalis superior) and lower (fovea costalis inferior) costal pits, which include the head of the rib.

Lumbar vertebrae (vertebra lumbalis) ( rice. 9) are distinguished by strictly horizontally directed spinous processes with small gaps between them, as well as a very massive bean-shaped body. Compared with the cervical and thoracic vertebrae, the lumbar vertebrae have a relatively small oval vertebral foramen.

The sacral vertebrae exist separately until the age of 18–25 years, after which they fuse with each other, forming a single bone - the sacrum (os sacrum) ( rice. ten, 43 ). The sacrum has the shape of a triangle with its apex down; a base is distinguished in it (basis ossis sacri) ( rice. ten, 42 ), top (apex ossis sacri) ( rice. ten) and lateral parts (pars lateralis), as well as the anterior pelvic (facies pelvica) and posterior (facies dorsalis) surfaces. Inside the sacrum passes the sacral canal (canalis sacralis) ( rice. ten). The base of the sacrum articulates with the fifth lumbar vertebra, and the apex with the coccyx.

The lateral parts of the sacrum are formed by fused transverse processes and vestiges of the ribs of the sacral vertebrae. Upper divisions the lateral surface of the lateral parts have articular ear-shaped surfaces (facies auricularis) ( rice. ten), through which the sacrum articulates with the pelvic bones.

The anterior pelvic surface of the sacrum is concave, with noticeable traces of fusion of the vertebrae (they look like transverse lines), forms back wall pelvic cavity.

Four lines marking the places of fusion of the sacral vertebrae end on both sides with the anterior sacral foramina (foramina sacralia anteriora) ( rice. ten).

The posterior (dorsal) surface of the sacrum, which also has 4 pairs of posterior sacral foramens (foramina sacralia dorsalia) ( rice. ten), uneven and convex, with a vertical ridge passing through the center. This median sacral crest (crista sacralis mediana) ( rice. ten) is a trace of fusion of the spinous processes of the sacral vertebrae. To the left and to the right of it are intermediate sacral crests (crista sacralis intermedia) ( rice. ten), formed by the fusion of the articular processes of the sacral vertebrae. The fused transverse processes of the sacral vertebrae form a paired lateral sacral crest (crista sacralis lateralis).

The paired intermediate sacral crest ends at the top with the usual superior articular processes I sacral vertebra, and below - modified lower articular processes of the V sacral vertebra. These processes, the so-called sacral horns (cornua sacralia) ( rice. ten), serve to articulate the sacrum with the coccyx. The sacral horns limit the sacral fissure (hiatus sacralis) ( rice. ten) - exit of the sacral canal.

Coccyx (os coccygis) ( rice. eleven, 42 ) consists of 3–5 underdeveloped vertebrae (vertebrae coccygeae) ( rice. eleven), having (with the exception of I) the shape of oval bone bodies, finally ossifying in a relatively late age. The body of the 1st coccygeal vertebra has outgrowths directed to the sides ( rice. eleven), which are vestiges of the transverse processes; at the top of this vertebra are modified upper articular processes - coccygeal horns (cornua coccygea) ( rice. eleven), which connect to the sacral horns. By origin, the coccyx is a rudiment of the caudal skeleton.

3. Movement of the spinal column

4. Age features spine

5. Chest

The chest is formed by the thoracic vertebrae, twelve pairs of ribs and the sternum - the sternum. The sternum is a flat bone in which three parts are distinguished: the upper one is the handle, the middle one is the body and the lower one is the xiphoid process.

Ribs are made up of bone and cartilage.

The structure of the chest

The structure of the sternum

The first edge lies almost horizontally. The anterior ends of the seven pairs of ribs are connected to the sternum with their cartilages. The remaining five pairs of ribs are not connected to the sternum, and the eighth, ninth and tenth pair are each attached to the cartilage of the overlying rib; the eleventh and twelfth pairs of ribs end freely in the muscles with their anterior ends. The chest contains the heart, lungs, trachea, esophagus, large vessels and nerves.

The chest takes part in breathing - thanks to rhythmic movements, its volume increases and decreases during inhalation and exhalation. The chest of the newborn has a pyramidal shape. Along with the growth of the chest, its shape changes. The chest of a woman is smaller than that of a man. The upper chest of a woman is relatively wider than that of a man. After illnesses, a change in the chest is possible: for example, with severe rickets, a chicken breast develops (the sternum sharply protrudes anteriorly).

Chest development

1 - cartilaginous thorax of a 4-week-old fetus 2 - chest of a 5 week old fetus 3 - chest of a 6 week old fetus 4 - newborn chest