Features of the structure of the human spine, its sections and functions, possible diseases with damage to bone structures and elastic elements. Anatomy of the spine

Why does a person need a spine? Just think about how important it is for the body. After all, in fact, it is a kind of body support, consisting of 32 or 34 vertebrae. All of them are connected to each other using joints, ligaments, and intervertebral discs. The latter are the so-called cartilages. It is important to know the structure of the spine so that if problems arise with it, they can be eliminated in a timely manner.

anatomy and structure

This part of the human body is quite simple in structure, because it consists of only a few sections, each of which, in turn, includes a certain number of vertebrae (they are usually called starting from the top):

cervical spine: consists of 7 vertebrae. It is important to note that the bone that is located on the back of the skull is not considered and is called the zero vertebra;
thoracic region: consists of 12 vertebrae;
lumbar region: consists of 5 vertebrae;
sacrum: consists of 5 vertebrae, which in an adult person fuse into the sacrum bone;
coccygeal region: consists of 3-5 vertebrae that fuse into one coccygeal bone.

Many of us have met more than once in medical literature human spine. His photo clearly demonstrates that the vertebrae are connected to each other by discs, articular processes, and ligaments (by the way, they are located in front, behind and on both sides of the vertebral bodies). Such a diverse connection of the vertebrae provides the mobility to man, which he was so generously endowed by nature. Everything is thought out to the smallest detail: ligaments are some kind of limiters that can hold the body, and the muscles located around the spine provide it with maximum movement. If the load on them is high, back pain and general malaise occur.

What functions does the spine perform?

First you need to understand that each part of the spine performs certain tasks related to the normalization of one or another part of your body. So, the functions of the human spine are divided into 5 sections:

Most important role in this case, the thoracic region plays a role; it is this that, together with the ribs and sternum as a whole, forms the chest. I would like to clarify that ribs are individual bones, which are attached to the spine, as if being an extension of it. The rib cage protects the organs and provides them with immobility. But due to the fact that there are joints between the ribs and the spine, we can freely inhale and exhale.
It is important that special pads in the form of discs are located between the thoracic and cervical regions. For example, due to the fact that there are cervical intervertebral discs, a person is able to tilt his head in both directions.

Now it is advisable to note the functions of the spine as a whole:

it serves as a certain shock absorber during falls, impacts, shocks;
located in the spine spinal cord, it is thanks to him that the body is a single whole (it connects the brain and all other parts of the body);
due to the fact that the human spine connects the entire body, the skeleton becomes rigid, and the head is easily held in an upright position;
promotes the mobility of a person, which he needs in life;
It is on the spine that all the major muscles and hips are supported.

What is the function of the cartilage discs between the vertebrae?

To begin with, it would be nice to understand what an intervertebral disc is. Speaking in simple words, this is a kind of layer between two adjacent vertebrae.

The shape is round, similar to a tablet. The structure of the intervertebral disc is very complex.

The center occupies which and is a shock-absorbing element with every movement of the spine. This happens because its structure is very elastic.

Please note that the vertebrae, despite their mobility, do not move relative to each other at all. This is all due to the fact that a fibrous ring is located around the core in the intervertebral disc. Its structure is complex due to large quantity different layers. This ring contains many fibers. All this connects and intersects in three directions. Strong and durable. But due to the fact that intervertebral discs tend to wear out over time, the fibers can gradually turn into scars. This disease is called osteochondrosis. By the way, it often causes strong painful sensations. In the end it may break and then surgical intervention it is unlikely to be avoided.

An interesting fact is that no vessels pass through the intervertebral disc of an adult. Some may object and ask how he eats then. This process occurs due to the penetration of oxygen and nutrients from the vertebrae located nearby (namely, from the vessels that penetrate them). Therefore, the medications that are often used to treat diseases associated with damage to the intervertebral discs are simply useless. Here it is better to resort to laser plastic surgery, then the effect will be one hundred percent.

Based on the above anatomical features, we can conclude what function the cartilaginous discs between the vertebrae perform. Firstly, they protect the spine from injuries due to excessive physical activity, falls, impacts, etc. Secondly, it is with the help of them that our body is flexible and able to actively move in different sides. It is important to know that the thickness of intervertebral discs can vary. It all depends on the part of the spine in which they are located:

cervical: 5-6 mm;

Thoracic region: the thinnest discs are 3-4 mm;

Lumbar: 10-12 mm.

Since in the cervical and lumbar regions The spine has a physiological forward curvature; one must understand that here the intervertebral discs will be slightly thicker.

If you look closely at the photo of the spine, you can easily see that the diameter of the intervertebral discs is 2-3 mm larger than the vertebrae themselves. I wonder if you knew that the length of the human spine changes throughout the day. In the morning it is 1 cm larger than in the evening. This is explained by the fact that during the day, under the influence of gravitational forces, the distance between the disks decreases, but during the night everything returns to normal. By the way, why does the structure of intervertebral discs change with age? This happens because their absorbency deteriorates, they wear out, and the spine becomes prone to damage. To prevent this from happening, it is necessary to exercise as much as possible throughout your life, spend time on fresh air and eat right. Thanks to these simple rules, the intervertebral discs are well saturated with oxygen. Then in old age nothing about intervertebral hernia there will be no speech.

Curves in the spine - is this normal?

Yes, the doctors’ answer is definitely positive.

With their help, a certain springy effect is formed that promotes walking, running, jumping and others. physical exercise. After all, the main functions of the human spine come down to creating maximum mobility of the body. Just imagine if a person had a straight spine. His photo clearly demonstrates the opposite; it is clearly visible that the vertebrae formed something like a wave:

lordosis in the neck - the spine in this place is slightly bent forward;
kyphosis in the chest - the spine is curved backward here;
lordosis in the lumbar region: the spine bends forward;
kyphosis in the sacrum area: a slight backward bend is visible.

This is absolutely natural look spine, and curves are considered its physiological feature.

Facet joints: anatomy. Intervertebral foramen

It is those processes that extend from the vertebrae that are called joints. Their anatomy is simple. In addition to the fact that intervertebral cartilaginous discs connect the vertebrae to each other, the facet joints also play the same role. These processes (look like some kind of arcs) are directed inward, as if looking at each other. At their end is located articular cartilage. Its nutrition and lubrication is provided by the fluid present inside the joint capsule. This is where the processes of the joints end. Main function facet joints is to ensure a certain mobility of the human body.

Intervertebral (foraminal) openings are created specifically so that veins pass through them and nerve roots. Their location is interesting: on both sides of each vertebra. They are formed with the help of articular processes, legs and bodies of two adjacent vertebrae.

How does the spine change with age?

Age-related anatomy and physiology are also characteristic of the spine. Although, it would seem, the spine is a rigid column, which is the basis of our entire body.

Of course, the structure of cartilage tissue allows us to perform a variety of movements, but nevertheless, the spine is a strong foundation, and it is very strange that time influences it. I would like to point out right away that this is completely normal. physiological feature human body. Throughout life, the human spine not only increases in length and gains a certain mass, but also undergoes significant changes:

During the first months of life, any child is in horizontal position, his spine is straight. Then there is a transition to a vertical position, due to which the spine acquires its characteristic physiological curves in their sections (cervical, thoracic, lumbar, sacral);
Over time, all cartilage tissue turns into bone. They say that in this way the spine becomes stronger;

The structure of the intervertebral disc is also subject to significant changes.

The age-related anatomy and physiology of the human spine is characterized by two main indicators:

The height of a person and the ratio of the proportions of his body throughout his life. There are certain average indicators that are considered normal and allow you to determine whether the spine is developing correctly. Indeed, in the first 20 years of a person’s life, the spine grows at the fastest pace, which can cause various abnormalities and diseases. That is why a child in the first years of life must be shown to specialists for prevention. various kinds diseases.
Growth of the spine by segment on average per year. This indicator calculated using a special formula, it also allows you to evaluate the development of the spine.

Spinal motion segment

A person has a certain functional unit, which represents the spinal motion segment. Essentially it is the connection of two adjacent vertebrae along with ligaments, discs, joints and everything else. Thus, we once again indicate what function the cartilaginous discs between the vertebrae perform. They are a special attachment that allows a person to perform various movements. Also, the mobility of the spine is created by the facet joints. Through special holes that pass through the side of the spine, nerve endings are pulled out and blood vessels. The spinal motion segment is a set of interconnected elements. Disruption of one of them entails a lot of consequences. It can manifest itself in two ways:

segmental blockade: adjacent vertebrae do not move, and the activity of the human body is carried out at the expense of other segments. In this case, pain often occurs;
segmental instability: the opposite situation, when the movements between adjacent vertebrae are excessive. In this case, not only pain occurs, but the problem can be hidden much deeper: the nerve endings are affected.

Remember that any pain in the spine can occur either in one specific place or everywhere at once. In any case, the source of the lesion can only be determined using special research and consultations with a competent specialist.

Nerve endings and spinal cord

The connection of the vertebrae also occurs inside the spine thanks to the spinal cord, the basis of the central nervous system person. Due to it (with the help of incoming signals from the brain), the work of the whole organism is regulated. The spinal cord is a large thread consisting of a huge number of nerve fibers and endings. It is located in the so-called "dural sac", which is well protected from external influence three different shells(soft, web-like, hard).

There is always a presence around him cerebrospinal fluid. Each part of the spine, and, accordingly, all the muscles, tissues, organs and systems located around it, is regulated by a certain part of the spinal cord.

Muscles located near the spine and their functions

It has already become clear that the main functions of the spine are to provide movement to a person. This is accomplished thanks to the muscles that are attached to the vertebrae. When we talk about back pain, we often don’t even suspect that the problem is not in the spine or discs. In fact, a specific muscle may be pulled. But complications in the spine can also cause involuntary contraction of nearby muscles, i.e. in fact, the opposite situation. When such a spasm occurs, lactic acid is produced in the muscle fibers (this oxidizes glucose), caused by a lack of oxygen access to the blood. This kind of pain is very familiar to pregnant women. They test it in labor activity during contractions due to improper breathing. But you just have to relax a little, and discomfort disappear as the spasm disappears.

Spinal problems

Initially, nature intended everything completely differently. After all, no one imagined that modern women and men will turn into motionless creatures, in the same (and for them absolutely uncomfortable) position throughout the entire working day. The spine becomes numb, experiencing incredible stress. But everyone knows one simple truth perfectly well: movement is life, and it’s hard to argue with that. Of course there is also great amount problems in this system, which are caused by poor ecology, improper and unbalanced diet, wearing uncomfortable clothes and shoes, etc. Correcting this situation is quite simple; you should follow a few simple tips:

conduct regularly active image life. Physical Culture and sport are the main helpers;
create comfort around you: comfortable furniture, clothes and shoes will help you relax during the working day;
preventively visit, for example, an orthopedist who is able to visual inspection identify problems with the spine. This is especially true for young children.

Back pain may also be caused by worn out intervertebral discs. Modern doctors love to talk about this to almost everyone. But in reality this rarely happens. Intervertebral disc degeneration can be caused by for various reasons, including unnecessary physical activity and tissue aging. Treatment usually involves surgery.

We have clearly understood what function the cartilaginous discs between the vertebrae perform. They provide proper movement to a person and, if possible, prevent damage to the spine. Do not think that pain that suddenly arises in the spine will necessarily go away on its own. It may subside for a while, but this is only the first signal of big problems.

Do not be lazy to promptly contact experienced and competent specialists who will help you prevent the development of serious diseases in the spine. After all, this is the basis of our entire body! The health of the entire body and that carefree old age that everyone dreams of so much directly depend on it. Take care of yourself and be healthy!

Anyone who does not take their own anatomy seriously does not take their own health seriously.

The structure of the spinal column

If wooden or concrete pillars each consist of homogeneous material, then the spinal column is heterogeneous. Its main components are the vertebrae. Almost everyone knows about the existence of vertebrae. There are 32 or 34 of them: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and from 3 to 5 coccygeal. The size and shape of the vertebrae are different. But they all have a body and an arch, between which there is a vertebral foramen. The vertebrae follow each other in turn: in the area of the sacrum and lower back they are larger, and the higher they are, the smaller they are. A bit like a children's pyramid, only the rings strung on a children's toy have an absolutely correct rounded shape, and the vertebrae have projections - processes: articular, transverse and spinous.

The rings of the children's pyramid, lying one on top of the other, form a through hole, and the vertebrae of our pyramid do the same. But this is not a simple hole - it is the spinal canal! Something much more important passes through it than the polished stick of a toy pyramid - the spinal cord is laid through the spinal canal, the nerve endings of which transmit information to the brain, receiving response commands from it.

There's no time for toys here. It is better to think again about the pole - a concrete pole of a power line that supports a wire that supplies energy to some control center.

But important communications are not only located inside the spinal column.

Through the holes in the transverse processes of the cervical vertebrae passes vertebral artery.

The structure of ligaments, muscles and joints of the spine

The spaces between the spinous processes of the vertebrae are occupied by ligaments and muscles.

The structure of the human spine. The articular processes connect with each other to form joints. In addition, the articular processes take part in the formation of the intervertebral foramina through which the neurovascular system of the spine passes.

But all this turns out to be not enough for our wonderful spinal column to function normally and uninterruptedly. Its work is also ensured by the intervertebral cartilages located between the vertebrae, which are called discs. They consist of a core and a fibrous, that is, fibrous, ring surrounding the core.

Spinal nuclei

The middle part of the disc, the nucleus pulposus, is especially important for the life of the spine and, consequently, the life of the entire organism. The nucleus has the shape of a biconvex lens and consists of a gelatinous substance (hence its second name - nucleus pulposus). The intervertebral discs of adults do not have vessels, so the supply of nutrients to them and the removal of metabolic products occurs through the vertebral bodies through diffusion, that is, the penetration of particles of one substance into another when they come into contact.

Thanks to its elasticity, the core is a wonderful shock absorber. Here you are lifting something heavy. The aggressive force begins to compress the vertebrae. The nucleus pulposus flattens as much as the elasticity of the annulus fibrosus allows it, losing a certain amount of fluid. But now you are letting go of the load. The pressure on the disk becomes more moderate, suction forces begin to prevail over compression forces, and the disk again actively accumulates water. After some time, the suction forces decrease and equilibrium is restored again.

The nucleus pulposus of the disc has another wonderful feature: it is able to absorb water even under significant compression forces, and work against them.

But the strength and endurance of the core are not infinite. Intervertebral discs in the structure of the human spine, these wonderful shock absorbers, like any other mechanism, have their own service life. Studies have established that the child has nucleus pulposus intervertebral disc contains 88% water, at 14 years old - 80%, and at 77 years old - 69%. This is clearly confirmed by the well-known own experience fact: over the years the spine becomes less resilient. In the language of science, the well-known truth looks like this: with age, the shock-absorbing capabilities of the core when exposed to tensile and compressive forces decrease. The gelatinous substance is no longer able to retain and absorb water under heavy loads. Old age is no joy. However, it is natural, there is no escape from it. The nuclei age, the exchange of fluid between the vertebrae and fibrous rings becomes difficult...

Fibrous rings of the spine

So we got to the fibrous rings of the structure of the human spine. Each of them, surrounding the core of the intervertebral disc, consists of dense bundles connective tissue, intertwined in different directions. These longitudinal, vertical, oblique and spiral weaves give the connection of adjacent vertebrae strength and mobility. In addition, the fibrous ring helps the nucleus, protects it, taking on part of the load.

And this help is by no means unnecessary - after all, the load is oh so great! Let's not talk about athletes and accelerators, let's imagine a person 165 cm tall and weighing 60 kg. It would seem - what is 165 cm by 60 kg! But when this person simply stands straight with his arms at his sides, his lower lumbar disc experiences a load of 30 kg.

But then he stretched his arms forward. Holds them horizontally. The disk became somewhat tense: the load increased to 66 kg.

Let's give him something in his hands. It doesn't matter what exactly. Let's say something weighs 10kg. The disk gasped - there is now 206kg of pressure on it!

And the person puts the load aside and bends slightly. In this case, the load on the disk reaches 60 kg.

The person bends even lower, the angle between the torso and legs reaches 90° - and now the pressure on the disc is already 210 kg, that is, compared to simply standing, the load has increased seven times! And if at the same time a person was holding, say, a thirty-kilogram load in his hands, then the compression force of the disk would increase to 480 kg!

And if he didn’t just hold the load, but lifted it, the pressure would increase many times more. But our spine can handle this too. Strengthen it thanks to the vertebrae, the nuclei of the intervertebral discs, the fibrous rings, to which part of the load is redistributed, the joints and, of course, thanks to the ligaments and muscles.

But here's what's interesting. If a person bends forward so that his fingertips can reach the floor, the force compressing the lumbar discs becomes much less than if he stood in a position corresponding to correct posture. This amazing circumstance is explained by the fact that in a deep tilt position, the muscles that hold the body in a vertical position or close to it are switched off from work. The body seems to hang on the stretched muscles and ligaments, which does not lead to any significant increase in intradiscal pressure: since the muscles are not contracted, but stretched, they do not pull adjacent vertebrae together.

From the above it follows that deep bends are useful, and half bends are harmful. This applies to both the cervical and lumbar spine. Otherwise: deep bends heal, but half bends cripple!

We will talk later about the enormous positive significance that stretching has for muscles. Now let's talk about the importance of muscles and ligaments for the well-being of the spinal column.

What parts does the skeleton consist of?

What are the functions of the skeleton?

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

Supportive, protective.

1. Name the features of the skull bones.

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

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

Just one bone lower jaw– movably connected to other bones. This allows us not only to grasp and chew food, but also to speak.

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

In humans, unlike mammals, the brain section, which is associated with an increase in brain volume.

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

The brain section of the skull consists of a frontal, an occipital, two parietal and two temporal bones. The facial section 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 - the foramen magnum. Through the foramen magnum, the brain connects to the spinal cord, and blood vessels pass through small openings.

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

The more stress the vertebrae experience, the more massive they are. That's why lumbar vertebrae, much more cervical.

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 capsule is formed, in which the spinal cord is located. The spine protects the delicate spinal cord from damage. Between the vertebrae there are intervertebral cartilaginous discs. Thanks to them, a semi-movable connection is formed. Cartilage tissue elastic and can be stretched and compacted. 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 and sternum semi-movably connected?

The rib cage is located in the upper part of the body. It is formed by the sternum ( middle part anterior wall of the chest), 12 pairs of ribs and the thoracic spine. The chest protects the heart and lungs located in it from damage. Ten pairs of ribs are movably connected (by joints) to the vertebrae and semi-movably (by cartilage) to the sternum. The two lower pairs of ribs are not connected to the sternum (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, they descend and push air out of them

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

The skull consists mainly of flat, immovably interconnected bones. The only movable bone of the skull is the lower jaw. The skull protects the brain and sensory organs from external damage, provides support for the facial muscles and the initial parts of the digestive and respiratory systems.

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

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

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 sensory organs will not be completely protected.

Question 3. What bones form the brain section of the skull?

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

Question 4. What role do the curves of the spine play?

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

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

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

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

The upper limb girdle is formed by two shoulder blades and two clavicles.

Question 7. What is the structure of the hand?

The brush is formed big amount small bones. It distinguishes three sections: the wrist, metacarpus and phalanges of the fingers.

Question 8. How are the structures 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 bones.

Question 9. What is a bony pelvis?

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

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

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

THINK

1. What causes a person to develop curves in the spine?

The spine has four bends, as a result of which its profile contour forms a wavy line. Curves that are convex forward are called lordoses, and curves that are convex backward are called kyphosis. There are cervical and lumbar lordoses, and thoracic and sacral kyphosis. The natural curves of the spine act like a spring. Thanks to these bends, elastic deformations occur in the spine (in response to the force of gravity) and wave shocks during walking or running.

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

2. How does the human skeleton differ from the mammalian skeleton?

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.

True ribs articulate only with the thoracic vertebrae (rudimentary ribs can also be found on other vertebrae). At the front they connect breastbone, forming the chest. The shoulder girdle consists of two shoulder blades and two clavicles. Some mammals do not have clavicles (ungulates), while others have them 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 are used by mammals to move on land, swim, fly, and grasp. 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.

IN hind limbs femur Most mammals have shorter tibiae.

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 (vertebras) that make up the spinal column has a through vertebral foramen (foramen vertebrale) inside ( rice. 8). 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 areas are clearly distinguished, distinguished by wider vertebrae. In general, the mass and size of the vertebrae increase from the upper to the lower: this is necessary to compensate for the increasing load that the lower vertebrae bear.

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 curves alternating in the spine are arranged in pairs: the curve facing forward (lordosis) corresponds to the curve facing backward (kyphosis). Thus, cervical (lordosis cervicalis) and lumbar (lordosis lumbalis) lordoses 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? Total in spinal column 32–34 vertebrae, separated by intervertebral discs and slightly different in their structure.

In the structure of an individual vertebrae, there is a vertebral body (corpus vertebrae) and a vertebral arch (arcus vertebrae), which closes the vertebral foramen (foramen vertebrae). The vertebral arch contains processes various shapes and purpose: paired upper and lower articular processes (processus articularis superior and processus articularis inferior), paired transverse (processus transversus) and one spinous process (processus spinosus), protruding backward from the vertebral arch. The base of the arch has the so-called vertebral notches (incisura vertebralis) - the upper (incisura vertebralis superior) and the lower (incisura vertebralis inferior). Intervertebral foramen (foramen intervertebrale), formed by the notches of two adjacent vertebrae, provide access to the spinal canal on the left and right ( rice. 3, 5 , 7 , 8 , 9 ).

In accordance with the location and structural features of the spinal column, five types of vertebrae are distinguished: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 3–5 coccygeal ( rice. 4).

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 first cervical vertebra, which does not have a body) is relatively small, oval shape and elongated in the transverse direction.

At the first cervical vertebra, or atlas ( rice. 5), the body is missing; its lateral masses (massae laterales) are connected by two arches - 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 first cervical vertebra is connected to the skull and the second 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 the axial vertebra.

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

Thoracic vertebra (vertebra thoracica) ( rice. 8) is distinguished by a large, compared to cervical, body and an almost round vertebral foramen. The thoracic vertebrae have on their transverse process a costal fossa (fovea costalis processus transversus), which serves to connect with the tubercle of the rib. On the lateral surfaces of the body thoracic vertebra there are also upper (fovea costalis superior) and lower (fovea costalis inferior) costal fossae, into which the head of the rib enters.

Rice. 8. VIII thoracic vertebra A - right view;B - top view: 1 - superior articular process; 2 - superior vertebral notch; 3 - upper costal fossa; 4 - transverse process; 5 - costal fossa of the transverse process; 6 - vertebral body; 7 - spinous process; 8 - lower articular process; 9 - lower vertebral notch; 10 - lower costal fossa; 11 - vertebral arch; 12 - vertebral foramen

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 to the vertebrae of the cervical and thoracic regions, the lumbar vertebra has a relatively small oval-shaped 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. 10, 43 ). The sacrum has the shape of a triangle, pointing downwards; it contains a base (basis ossis sacri) ( rice. 10, 42 ), apex (apex ossis sacri) ( rice. 10) and lateral parts (pars lateralis), as well as the anterior pelvic (facies pelvica) and posterior (facies dorsalis) surfaces. The sacral canal (canalis sacralis) runs inside the sacrum ( rice. 10). The base of the sacrum articulates with the V lumbar vertebra, and the apex with the coccyx.

The lateral parts of the sacrum are formed by fused transverse processes and rudiments of the ribs of the sacral vertebrae. Upper sections the lateral surface of the lateral parts have articular ear-shaped surfaces (facies auricularis) ( rice. 10), 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 fusion of the sacral vertebrae end on both sides with the anterior sacral foramina (foramina sacralia anteriora) ( rice. 10).

The posterior (dorsal) surface of the sacrum, which also has 4 pairs of posterior sacral foramina (foramina sacralia dorsalia) ( rice. 10), uneven and convex, with a vertical ridge running through the center. This median sacral ridge (crista sacralis mediana) ( rice. 10) is a trace of fusion of the spinous processes of the sacral vertebrae. To the left and right of it are the intermediate sacral ridges (crista sacralis intermedia) ( rice. 10), formed by the fusion of the articular processes of the sacral vertebrae. The fused transverse processes of the sacral vertebrae form the 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 - the modified lower articular processes of the V sacral vertebra. These processes, the so-called sacral horns (cornua sacralia) ( rice. 10), serve to articulate the sacrum with the coccyx. The sacral horns limit the sacral hiatus (hiatus sacralis) ( rice. 10) - 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 that finally ossify in a relatively late age. The body of the first coccygeal vertebra has outgrowths directed to the sides ( rice. eleven), which are rudiments of transverse processes; At the top of this vertebra there 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.

Vertebral connections
	Sagittal cut at the level of two lumbar vertebrae. 1-vertebral body; 2-nucleus pulposus of the intervertebral disc; 3-anterior longitudinal ligament; 4-fibrous ring of the intervertebral disc; 5-superior articular process of the lumbar vertebra; 6-posterior longitudinal ligament; 7-intervertebral foramen; 8-yellow ligament; 9-articular capsule of the facet (intervertebral) joint; 10-interspinous ligament; 11th supraspinous ligament.

3. Movement of the spinal column

4. Age characteristics spine

5. Chest

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

Ribs are made of bone and cartilage.

Structure of the chest

Structure of the sternum

The first rib lies almost horizontally. The anterior ends of seven pairs of ribs are connected to the sternum with their cartilage. The remaining five pairs of ribs are not connected to the sternum, but 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 a newborn has a pyramidal shape. As the chest grows, its shape changes. A woman's chest is smaller than a man's. A woman's upper chest is relatively wider than a man's. After illnesses, changes in the chest are possible: for example, with severe rickets, a chicken breast develops (the sternum protrudes sharply to the front).

Development of the chest

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