The structure of the cervical vertebra and intervertebral disc. The structure of the spine. Role and functions in the body

Instruction

The first vertebra is C1, (atlas). Named after the titan Atlanta, who holds the sky. So he seems to be holding on to himself. In fact, the atlas is only a link with the rest of the spine. It does not have a body, but is actually a ring consisting of two arches: anterior and posterior, interconnected by lateral masses and two lateral formations. It is attached to the occipital foramen with the help of condyles, and from below its articular surface is almost flat. On the posterior arch it has a small cavity, with which the tooth of the second vertebra docks. It has a very large vertebral foramen so that in the event of sudden movements and a slight displacement that may subsequently follow, there will be no damage to the spinal cord.

The second vertebra, C2, is called the epistrophy (axis). It is unique in that during the formation of the skeleton in the embryonic period, the body of the first vertebra adheres to it, forming the so-called tooth. At the top of the tooth are the anterior and posterior articular surfaces, the anterior connects to the fossa on the atlas, and the posterior to its transverse ligament. The atlas with the occipital bone moves around it, as if around its axis, which is why it is also called the axial vertebra. The spinous process is very strong and large, much more massive than the rest of the cervical vertebrae.

The third, fourth, fifth and sixth vertebrae - C3, C4, C5, C6 do not have their own names (vertebra cervicalis). In fact, they are no different from each other, so they are simply called by a serial number, for example, the fourth vertebra or the sixth vertebra. Since there is no great pressure on the cervical vertebrae, they are small and have low bodies, which explains the high probability of injury to this part of the spine. Each of them has an almost triangular vertebral foramen, and the transverse processes have an opening through which the vertebral artery passes. The ends of the transverse processes have two tubercles: anterior and posterior. The anterior tubercle of the sixth vertebra is slightly better developed, therefore, with severe bleeding, the common carotid artery can be pressed against it. The spinous processes of these four vertebrae are relatively short.

The seventh vertebra - C7 does not have its own name, but for small differences in structure it is called a protruding vertebra (vertebra prominens). Since it has a very long spinous process, which is easily felt through the skin, and it is used to count the vertebrae during examinations of patients. Otherwise, its structure is actually completely identical to the four previous vertebrae.

The spine consists of several sections, each of which performs its function in the human body. In our article, we will take a closer look at the cervical vertebrae, the anatomy of this department has its own unique features. They are the most mobile and small in the spine, but are important in the performance of the whole organism.

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Anatomical features

The cervical spine in humans consists of seven vertebrae, in total there are thirty-four of them in the body. This is the most mobile part of the column, which is responsible for the movements of the neck and head. It is this region that is most often exposed to traumatic lesions. This happens due to the weakness of muscle tissue compared to other parts of the body, and the vertebrae are less strong and small in size.

The structure of the cervical region has its own characteristics - the first, second and last vertebrae differ from the rest. The first is called Atlas, and its damage leads to serious consequences for the body. Since it connects the head and spine.

What are they made of?

In the structure of the vertebra, a body and an arc are isolated, which closes the vertebral foramen. On the arc there are processes of various shapes - paired, paired transverse and spinous. The arc at its base has upper and lower notches. The hole inside the vertebra is formed by cuttings of two adjacent vertebrae.

Differences of the cervical vertebrae:

• hole in the transverse processes;
• the triangular opening is enlarged in comparison with the same in other departments;
• the body is smaller and oval in shape, which is elongated in the transverse direction. The exception is the Atlantean - he does not have a body at all.

Vertebrae form bones. The body is the front part, and the arc with all processes is located behind. In the middle between them, a hole is formed through which the canal with the spinal cord passes. This is how a typical vertebra is built. Its body has a concave shape. And from the third to the sixth, they have a specific upper part - the edges on the sides seem to rise slightly upward, forming a hook.

The vertebral foramen resembles a triangle, has a fairly large size. And the processes are short in length, located at an angle, with flat, slightly convex surfaces. From the second vertebra onwards, the body has spinous processes that become longer in length. At the end they have a split and a slight downward slope.

There are also small processes that are located in different directions from each other. On top of them is a deep groove, inside which the nerve of the spinal cord passes. The beard is located in the middle between two tubercles (posterior and anterior), which are located at the end of the transverse process.

On the sixth vertebra, there is a larger anterior tubercle, since the carotid artery passes in front of it. When bleeding occurs, it is pressed against this tubercle. The vertebral bodies have a transverse process, which is formed by two other processes. The front is a vestige of the rib, but the back is just a process. Each of them frames the opening of the transverse process, in which the blood vessels pass.

Such a complex structure of the vertebrae is necessary for the careful protection of the spinal cord, which is responsible for the functionality of many organs and limbs.

How many are counted?

So, as we already wrote, the number of vertebrae in the cervical region is seven pieces. The first one is Atlas, and the next one is called Axis. They connect the skull and spine with the help of the so-called atlantoaxinal-occipital junction. The first two vertebrae have their own special structure. Between them there are three joints, two paired, and the third is located at the junction of the odontoid process of the axis with the arch of the atlas.

The atlas has no arch and body, like the rest of the vertebrae. It has a special structure in the form of a ring from the anterior and posterior arches. They are fastened with elements oval on top and flat on the bottom. This is where the occipital bone touches. The lower flat part has a connection point with the axis. The anterior arch forms a tubercle, and the posterior arch forms a slight depression that connects to the tooth of the body. But on the posterior arch of the spinous process is the posterior tubercle, there is a groove for the artery.

The second vertebra also has a specific shape. It is the axis on which the head is located and rotates. On the axis there is a tooth (directed upwards) with a sharp apex. On it, as on a hinge, the atlas and the whole head are attached. In front of the tooth is the area to which the tooth of the first vertebra is attached. Behind the tooth is the back of the joint, to which the ligament from the atlas is attached.

The third, fourth, fifth and sixth vertebrae are absolutely typical, we have described their structure above. But the seventh has its own characteristics. He has a larger spinous process than the rest, which does not divide into two parts. There are also transverse ones, which have a considerable length. At the same time, the transverse openings are practically invisible, and on the side of the body there is a recess in which the cervical region is connected to the first rib.

Role and functions in the body

The first two vertebrae are responsible for the attachment and rotation of the cranium. If the atlas is damaged, it can adhere to the skull, this is a serious injury. It disrupts the motor ability of the skull and its blood supply.

Functions of the third - seventh vertebrae: supporting, motor, protective for the spinal cord. Each transverse process has an opening for the spinal artery. Due to this structure, the cervical region allows you to perform the actions of flexion, extension, side bending, circular and rotational movements, as well as along the vertical axis.

To perform these functions, the cervical muscles and ligaments are important, which allow this department to be both mobile and mobile. The sixth vertebra is worth noting separately. It is also called the carotid tubercle, as the carotid artery passes next to it. Since there is a high risk of injury to this artery, nature intended a stronger development and mobility of the tubercle in this vertebra.

Each vertebra performs its own specific function, while together they represent a whole system of protection for the spinal cord and interaction in movements. With violations in the vertebrae, for example, a hernia, protrusions, a person begins to feel bad. There are pains, dizziness, nausea, as the head is poorly supplied with food, the nerve endings are clamped.

Detailed structure

The spine is a whole system, and the vertebrae in it make up only one part of it. They consist of bones and, located on top of each other, form a pillar. Above we have already considered their detailed structure. There are discs between the vertebrae. They are a gasket between bone structures, absorbing all movements, and also perform a connecting function.

Ligaments are located in the spine to hold the bones together. And between the vertebrae, facet joints are located, creating the opportunity for the spine to move. And of course the muscles that surround the spine and allow it to maintain its position and move.

Inside the spinal column runs the spinal cord, which is part of the human central nervous system. Through it impulses go from the brain to all organs of the human body. Each department is responsible for its own set of organs and body parts. The spinal cord has nerve roots that extend beyond the vertebrae through the openings of their legs and processes.

Ligaments and bone structures

The vertebrae are formed from spongy bones. That is, they are represented by two layers - the outer cortical and the inner spongy. The latter is similar to a sponge, as it is formed from beams, between which there is a space filled with bone marrow.

The main ligaments are longitudinal and yellow. The first is responsible for connecting the vertebral bodies from the back, and the second ligament unites the arcs of different vertebrae. With traumatic lesions or ailments of the joints and discs between the vertebrae, the ligaments try to restore the normal position of the parts of the spine. This leads to their overstretching.

Intervertebral discs

This is a layer between the vertebrae of a round shape. It has a complex structure of fibrous tissue with a nucleus in the center. The fibrous ring is represented by many intersecting fibers. They are strong enough and keep the shape of the disk, protecting the core inside and not allowing the vertebrae to move. But with the development of degenerative diseases, such as osteochondrosis, fibrous tissue is replaced by scar tissue. In this case, the disc becomes weak, shrinks when exposed to the vertebrae, may burst, then a hernia appears in a person.

muscles

There are muscles around the spine that support it, provide the ability to bend over, turn the neck. Muscles are attached to the processes. With pain in the neck, often the cause is precisely the pain syndrome in the muscle tissue. With physical exertion, or diseases of the spine, their stretching often occurs. This happens due to an attempt by the muscles to stabilize the damaged area, spasm occurs, the accumulation of lactic acid and as a result of squeezing of blood vessels.

In childhood, the development of muscle tissue around the spine is responsible for the healthy development of the newborn. Spasms and tissue tone can cause delays in physical and mental development. There is, for example, a symmetrical tonic neck reflex. Its timely detection and treatment can prevent pathological changes in joint mobility at the time of teaching the child the simplest actions (sitting, walking).

This reflex develops at the level of the first, second and third vertebrae in the cervical region. Diagnosed with tests. For example, in the supine position, the head bends, at this moment flexion in the arms and extension in the legs reflexively occur.

Spinal cord

This is a department in the central nervous system, it is a collection of many nerve cells surrounded by three shells. The last solid contains the brain itself and a couple of centimeters of nerve roots. Each section of the spinal cord is responsible for a specific part of the human body. The cervical part is connected by nerve endings to the neck and upper limbs. Due to nerve impulses, information is exchanged between these departments and the brain. Injury to the spinal cord can cause paralysis of the limb.

intervertebral foramen

They are also called foraminal. They are located on the side of the vertebrae, forming from the legs, bodies and processes of adjacent vertebrae. Nerve endings come out of the inner part of the column through them, and veins and arteries enter inside for nutrition. Such holes are located on each side of the two connecting vertebrae.

Facet joints

Adjacent vertebrae are joined together by two joints, which are located symmetrically to the midline in the body from the arch on both sides. The processes from two vertebrae are located in the direction of each other, their ends are enveloped by cartilaginous tissue. It is smooth and slippery, due to which the articular surfaces can move easily, without unnecessary friction. The ends of the bones are surrounded by a bag of articulation, which is filled with shock-absorbing joint fluid.

Video "The structure of the atlas"

In the video you will see in detail what the atlas looks like and how it is attached to the skull and spine.

The spinal column consists of vertebrae assembled in an S-shaped structure, which ensures the musculoskeletal function of the entire skeleton.

The structure of a human vertebra is both simple and complex, so what parts it consists of and what function it performs will be discussed below.

The spine is the main part of the human skeleton, ideally adapted to perform a supporting function. Due to its unique structure and cushioning capabilities, the spine is able to distribute the load not only along its entire length, but also on other parts of the skeleton.

The spine consists of 32-33 vertebrae assembled into a mobile structure, inside which is the spinal cord, as well as nerve endings. Intervertebral discs are located between the vertebrae, thanks to which the spine has flexibility and mobility, and its bone parts do not touch each other.

Thanks to the structure of the spine ideally created by nature, it is able to ensure the normal functioning of a person. He is responsible for:

• creation of a reliable support during movement;
• proper functioning of organs;
• combining muscle and bone tissues into one system;
• protection of the spinal cord and vertebral artery.

The flexibility of the spine is developed individually for everyone, and depends primarily on the genetic predisposition, as well as on the type of human activity.

The spinal column is a skeleton for attaching muscle tissues, which in turn are a protective layer for it, as they take on external mechanical influences.

Support corset for the spine

Departments of the spine

The spine is divided into five sections.

Table number 1. The structure of the vertebrae. Characteristics and functions of departments.

The structure of the vertebra

The vertebra is the main component of the spinal column.

In the center of each vertebrae there is a small opening called the spinal canal. It is reserved for the spinal cord and vertebral artery. They run through the entire spine. The connection of the spinal cord with the organs and limbs of the body is achieved through nerve endings.

Basically, the structure of the vertebrae is the same. Only fused areas and a couple of vertebrae, designed to perform certain functions, differ.

The vertebra consists of the following elements:

• body;
• legs (on both sides of the body);
• spinal canal;
• articular processes (two);
• transverse processes (two);
• spinous process.

The vertebral body is located in front, and the processes are behind. The latter are the link between the back and the muscles. The flexibility of the spine is developed individually for everyone, and it depends, first of all, on the genetics of a person, and only then - on the level of development.

The vertebra, due to its shape, ideally protects both the spinal cord and the nerves extending from it.

The spine is under the protection of the muscles. Due to their density and location, a layer is formed like a shell. The thorax and organs protect the spine from the front.

This structure of the vertebra was not chosen by nature by chance. It allows you to maintain the health and safety of the spine. In addition, this shape helps keep the vertebrae strong for a long time.

Vertebrae of various departments

The cervical vertebra is small in size and elongated across the shape. In its transverse processes there is a relatively large triangular opening formed by the vertebral arch.

Thoracic vertebra. In his body, large in size, there is a round hole. There is a costal fossa on the transverse process of the thoracic vertebra. Connecting a vertebra to a rib is its main function. There are two more pits on the sides of the vertebra - the lower and the upper, but they are costal.

The lumbar vertebra has a large bean-shaped body. The spinous processes are located horizontally. There are small gaps between them. The spinal canal of the lumbar vertebra is relatively small.

The sacral vertebra. As a separate vertebra, it exists until about 25 years old, then it fuses with others. As a result, one bone is formed - the sacrum, which has a triangular shape, the top of which is turned down. This vertebra has a small free space reserved for the spinal canal. The fused vertebrae do not stop performing their functions. The first vertebra of this department connects the sacrum with the fifth lumbar vertebra. The apex is the fifth vertebra. It connects the sacrum and the coccyx. The remaining three vertebrae form the surfaces of the pelvis: anterior, posterior and lateral.

The vertebra at the coccyx is oval. It hardens late, which compromises the integrity of the coccyx, since at an early age it can be damaged as a result of a blow or injury. At the first coccygeal vertebra, the body is equipped with outgrowths, which are rudiments. In the upper part of the first vertebra of the coccygeal section, the processes of the joints are located. They are called coccygeal horns. They connect with the horns located in the sacrum.

If you want to know in more detail the structure, and also consider what each vertebra is responsible for, you can read an article about this on our portal.

Features of the structure of certain vertebrae

The atlas consists of anterior and posterior arches joined together by lateral masses. It turns out that the atlas has a ring instead of a body. Branches are absent. Atlas connects the spine and skull thanks to the occipital bone. The lateral thickenings have two articular surfaces. The upper surface is oval, joins the occipital bone. The lower round surface connects to the second cervical vertebra.

The second cervical vertebra (axis or epistrophy) has a large process that resembles a tooth in shape. This offshoot is part of Atlanta. This tooth is the axis. Atlas and the head revolve around it. That is why the epistrophy is called axial.

Due to the joint functioning of the first two vertebrae, a person is able to move his head in different directions without experiencing problems.

The sixth cervical vertebra is distinguished by costal processes, which are considered vestigial. It is called protruding because its spinous process is longer than that of other vertebrae.

If you want to learn more and also consider the functions of bends, you can read an article about this on our portal.

Diagnosis of diseases of the spine

Vertebrology is a modern branch of medicine in which attention is paid to the diagnosis and treatment of the spine.

Previously, this was done by a neuropathologist, and if the case was severe, then an orthopedist. In modern medicine, doctors trained in the field of spinal pathologies do this.

Today's medicine provides doctors with numerous opportunities for diagnosing diseases of the spine and treating them. Among them, minimally invasive methods are popular, because with minimal intervention in the body, a greater result is achieved.

In vertebrology, diagnostic methods that are able to produce results in the form of images or other types of visualization are of decisive importance. Previously, the doctor could only prescribe an x-ray.

There are now many more options that can provide accurate results. These include:

• CT scan;
• myelography;
• electroneurography;
• electromyography.

Moreover, today in medical practice, vertebrologists often use a map of segmental innervation. It allows you to associate the cause and symptoms with which vertebra is affected and which organs it is associated with.

Table No. 2. Map of segmental innervation

Anatomy in Chinese

Even several thousand years before mankind invented radiography, Chinese doctors already knew about the connection between the internal organs of a person and the spine.

Based on the theory of acupuncture, the main knowledge that we received from the ancient Chinese is the knowledge of bioactive points that have a direct effect on the internal organs. These points are located near the spine.

Depending on the localization of pain, we can talk about the disease itself. To get rid of it, you need to act on the sore spot. This can be achieved with the help of hands (massage) or various means (for example, special needles).

Video - Acupuncture

The ideas of Chinese physicians of that time about the connection between internal organs and vertebrae are completely similar to the map of segmental innervation, which modern doctors have.

Moreover, Chinese scientists in ancient times came to the conclusion that emotions affect the physical state. They were able to create a system for identifying diseases based on emotions. The main emphasis is on which emotional component harms a particular organ.

Table No. 3. Chinese health map.

Modern medicine on a scientific basis fully confirms all the knowledge that the Chinese scientists of ancient times shared with us.

Treatment

Physiotherapy devices

There are many options for the treatment of the spine, which are carried out in stationary conditions. However, besides them, there is a simple and affordable way of healing - this is oriental massage. Everyone can master it and do it at home.

According to Chinese tradition, human bioactive points are located not far from the above vertebrae (see table No. 2). The distance is two fingers.

At a distance of four fingers are the points where, according to Chinese doctors, destructive emotions accumulate. Walking along the entire length of the spine with just the tips of your fingers, the massage therapist improves the functioning of the whole organism.

Movements are done gently along the spine. You need to move from the highest point down.

The main rule of massage. A person who is being massaged should enjoy the process and not experience pain. If pain occurs when you press on any point, then you need to ease the pressure.

A simple massage, when performed correctly, can improve the condition of the human body. But the main thing is to get rid of the causes that cause negative emotions. After all, they are usually the root cause of all problems.

Video - Oriental massage Yumeiho

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It serves as the basis of the body's skeleton and one of its most important systems.

Its tasks include protecting the spinal cord and the need to maintain the trunk in an upright position.

Among the most significant functions of the spine, it is possible to single out the protection of the brain from concussion during movement, which is provided by shock-absorbing properties.

The greatest fragility and susceptibility to various injuries of the spine among all the others is precisely cervical region.

In order to avoid damage to it, it is necessary to know the features of its structure and safety measures during physical activity.

Features of the structure of the cervical spine

The human spine is made up of 24 vertebrae and four sections.. Each of them has significant differences in its structure and number of vertebrae. In the thoracic region, they are largest in size.

In the lumbar region, they are located very close to each other, and as they approach the coccygeal zone, they become fused. The cervical spine is considered the most fragile, but it is its thin structure that provides the quality of mobility and allows you to make a variety of head movements.

The cervical region consists of seven vertebrae. Each of them differs in its structure. Due to their small size and weakness of the neck muscles, this section is often injured.

The peculiarity of the structure of the cervical vertebrae is significant differences from the vertebrae of all other parts of the spine. Most vertebrae consist of an anterior section called the vertebral body, which is cylindrical in shape; the spinal cord, located inside the spine from behind, is limited by the arch of the vertebra; they also have spinous processes pierced by holes for blood vessels.

The structure of the cervical vertebrae is different, which is due to the peculiarities of their functions, including fastening with the skull, protecting the spinal cord, providing nutrition to the brain and performing various head movements.

The structure and functions of the cervical vertebrae

The very first vertebra of this department, located at the top, is called the "atlas". It is axial, has no body and spinous process. In this area, it allows you to connect the spinal column with the bone of the neck, as well as the brain and spinal cord between themselves.

These tasks its structure is determined: it consists of two arches that border the spinal canal. The anterior arch forms a small tubercle. Behind it is a depression, combined with the odontoid process of the second vertebra.

A groove is located on the posterior arch, where the vertebral artery is placed. The articular part of the "atlas", located on top, has a convex shape, and the lower one is flat. This feature of the structure is due to the intermediate position of the vertebra between the spine and the head.

Second vertebra, called "axis", is also distinguished by its shape, which resembles a pointed "tooth". It performs the functions of a “hinge”, which ensures the rotation of the first vertebra of the “atlas” together with the skull, as well as the ability to tilt the head in different directions.

There is no intervertebral disc in the space between the "atlas" and "axis". Their connection is formed by the type of joint. It is this factor that determines the high risk of injury.

Cervical vertebrae from the third to the sixth are small. Each of them has a fairly large hole, similar in shape to a triangle. Their upper edges protrude slightly, which is why they are compared with "sides". Their articular processes are short and at a slight angle.

The vertebrae from the third to the fifth also have small transverse processes that are split along the edges. In these processes there are openings through which blood vessels pass. It is here that the main vertebral artery that feeds the brain is located.

On the next section, where the sixth and seventh vertebrae are located, the spinal column has a slight expansion. Salt deposition occurs most often here. The sixth vertebra is called "sleepy" because its tubercle, located in front, is located near the carotid artery. It is to him that the artery is pressed to stop the bleeding.

The largest in the last section of the cervical region here is the seventh vertebra. You can feel it with your hands if you tilt your head forward. For the same reason, he is also called a speaker. In addition, it serves as the main reference point when counting the vertebrae. The lower part of this vertebra has a depression.

Here is the place of its connection with the first edge. A feature of the seventh vertebra is the openings in the region of the transverse processes, which can be very small in size, or completely absent. It has the longest spinous outgrowth, without division into parts.

Each of the cervical vertebrae is responsible for a specific function.

When they are damaged, unpleasant phenomena occur that correspond to each specific vertebra, such as:

Paravertebral muscles of the cervical spine

And did you know that…

Next fact

The muscle tissues of this spine are divided into two parts: back and front. The muscles located in front are divided into superficial, deep and middle.

The main functions of the tissues of the neck muscles are as follows:

• keeping the skull in balance;
• providing head movement: rotations and tilts;
• ensuring the processes of swallowing and voice function.

The muscle tissues of the cervical region are connected with the help of special fascia and blood vessels, which serve as natural limiters of different areas.

There are several main muscle groups:

• subcutaneous muscles;
• muscles covering the surface of the neck;
• scapular-clavicular muscles, necessary to form a place for placing muscle tissue above the chest.

The muscles located inside the neck are made up of visceral plates needed to line the organs inside the neck. They form the areas in which the veins and the carotid artery are located. A plate placed in front of the vertebra is needed to form a site for placing deep muscles.

Physiological curves of the cervical spine

The cervical spine has a natural forward curve. It is called lordosis. This curvature is compensated by kyphosis, another curvature directed backward in the thoracic region. Such bends give the spine elasticity, allow you to endure the daily loads caused by upright walking.

Curves of the spine are not congenital. In order for them to form properly, appropriate care and lifestyle are needed.

Physiological is considered cervical lordosis up to 40 degrees. If the angle exceeds this figure, pathological lordosis is diagnosed. A person with a similar pathology is easy to notice by a sharply advanced head, which is set rather low.

Cervical lordosis may be: Diseases of the cervical region are possible due to various injuries after a strong blow or as a result of a fall. In some cases, the risk of injury exists even when the head is tilted or turned sharply, for example, when diving into water.

The most common pathologies in the region of the cervical spine are::

• ruptures of ligaments and intervertebral discs;
• displacement of the vertebrae;
• fractures.

Serious injuries of this department are dangerous because they can hurt the spinal canal. The result can be paralysis, heart failure, or death. The danger of such injuries is also due to the fact that the severity of the situation can not always be assessed immediately. At first, only soreness during movement or swelling can indicate pathology.

Conclusion

cervical spine includes seven vertebrae, the structure of which differs markedly from the structure of the rest of the spinal column.

Each of the vertebrae of this department performs certain functions. Damage to any of them can cause certain pathologies of the body.

The difference between these vertebrae lies in their small size and special fragility.. Their shape is cylindrical, inside is the spinal cord.

The main functions of the cervical region are providing anchorage with the skull, nutrition for the brain, making a variety of head movements.

To ensure the same processes, the muscles of the neck serve, which also affect the processes of voice formation and swallowing.

The cervical region has a natural curve - lordosis, the correct formation of which occurs in the first years of human life and depends on the environment.

The most common diseases of the cervical spine are associated with various injuries, which are dangerous in that they may not be noticed immediately, but pose a risk of developing cardiac pathologies, paralysis, or even death.

Test!

The cervical spine consists of 7 vertebrae, this segment is the most mobile. The craniovertabral transition is the upper part of the cervical segment, which consists of vertebrae such as the atlas, axis, and the occipital base of the skull. This articulation provides neck mobility. In the same area there are blood vessels that supply blood to the brain, as well as the bulb of the brain (posterior part of the brain), which regulates vital functions (vegetative, motor, sensory).

The first cervical vertebra is subjected to the greatest load, it supports the skull, spinal cord, vertebral arteries, has points to which the neck muscles are attached. His tension is further enhanced by the fact that his head is constantly moving. Its structure differs from other vertebrae, which allows it to function normally.

Structure

The spine starts from the atlas, this vertebra is also called C1 or atlas. It is located under the condyles (ball-shaped end of the bone) of the occipital bone and above the second cervical vertebra (C2, axis). The atlas can be felt with your fingers, with its correct location, normal head mobility is maintained, and the body functions normally.

The anatomy of the atlas differs from other cervical vertebrae. This is the thinnest element of the spine, which has an annular shape and several small protrusions. 1 cervical vertebra does not have a body, instead, an anterior arch is located at its anterior end, the most convex part of which is called the anterior tubercle. The anterior arch curves backwards as well as on the sides of the tubercle, and its posterior surface is smooth. On the back surface of the anterior arch there is an articular recess for the tooth of the second cervical vertebra (axis).

The widest sections of C1 are located to the right and left of the anterior arch. On each lateral mass (thickness) there are oval depressions that have a smooth surface, they are called articular facets. The condyles of the occipital bone are attached to these recesses, so the atlantooccipital articulation is formed. This bony connection allows for flexion as well as extension of the neck. On the lower surface of each lateral mass there are articular depressions that provide articulation with the axis (C2). This forms the atlantoaxial joint.

On the sides of each lateral mass are extensions called transverse processes, inside of which there are openings for the vertebral arteries, as well as veins that run through the neck. These bony structures protect blood vessels from damage. In addition, muscles responsible for neck movements are attached to the transverse processes.

The posterior arch extends from the transverse openings, which closes the ring of the atlas, and inside it there is a vertebral foramen. A thin annular vertebra has an expansion only in the posterior area, where a tubercle is formed. Its structure and functions are similar to many spinous processes. Depressions on each side of the posterior arch serve to exit the nerve roots from the vertebral foramen, and also allow the vertebral artery to pass into the foramen magnum through the cavity in the spinal column.

You can study the structure of the atlas in the photo above, which shows its top and bottom views.

Thus, it is possible to distinguish the main distinguishing features of the structure of the atlas from other vertebrae:

• C1 has no body.
• Instead of a body, the atlas has lateral masses that are connected by anterior and posterior arches.
• Atlas has a tubercle in front as well as behind.
• On the inner side of the anterior arch there is an articular depression for the articulation of the atlas with the axis. This bony connection maintains the mobility of both vertebrae.
• Between C1 and C2 there is a movable joint, which provides movement of the head.

These are the main features of the atlas that none of the other vertebrae have.

Atlas functions

The C1 vertebra supports the skull and also provides movement for the head and neck. The bony connection between the occipital bone and the atlas allows the flexion and extension of the neck with the help of several muscles. The atlantoaxial joint provides lateral flexion, rotation of the head in different directions. Most of the muscles of the neck are involved in turning the head, but some of them (including the rectus lateralis, as well as the oblique muscles of the head) are attached to the transverse processes of the atlas. Several muscles connect the transverse processes to the axis, allowing the neck to be flexed laterally towards the shoulders.

C1 forms a bony ring that protects the spinal cord, as well as the nerve roots emanating from it, from damage. The vertebral foramen of the atlas has a larger diameter than that of other vertebrae, which allows the soft nervous tissue to move freely when the neck is flexed or rotated. The transverse openings protect the vertebral arteries, veins that provide nutrition to the brain. These bony structures prevent the blood vessels from being compressed or damaged.

Atlantoaxial joint

As mentioned earlier, the axis is placed under the atlas. The 1st and 2nd vertebrae form the atlantoaxial joint. The structure of the axis or axial vertebra differs from C1, this is noticeable in the photo below.

Axis - second cervical vertebra

This bone connection is combined, it contains 3 separate joints: median, and 2 lateral. The median joint consists of the anterior and posterior articular depressions of the atlas, which articulate with the fossa of the tooth, the C1 transverse ligament, stretched between its lateral masses. This is a cylindrical uniaxial bone connection that allows you to turn your head left and right. Atlas, together with the skull, can rotate around tooth C2 by 30 - 40 ° in both directions.

The lateral atlantoaxial joint is a paired bone joint (right and left). It consists of the lower articular cavity C1, as well as the upper articulating surface C2. This is a flat multi-axial connection that provides rotation of the skull when the atlas moves around the odontoid process of the axial vertebra.

The median and lateral joints have separate articular capsules, they are reinforced with ligaments. The fixation of the odontoid process during its rotation around C1 is carried out by the cruciate ligament. It is formed by the transverse ligament of the atlas, as well as 2 bundles (upper and lower), which pass up to the foramen magnum, and then down to the back of C2.

Reference. The cruciate ligament fixes the tooth, directs its movements. In addition, she does not allow his dislocation, damage to the spinal cord, as well as the medulla oblongata, which can lead to death.

The pterygoid ligaments are located on the sides of the odontoid process, they rise to the occipital bone. The apex ligament is a thin bundle that runs from the top of the process to the base of the skull.

Not all people know what the atlantooccipital joint is. This bony connection that connects the skull to the cervical spine, it consists of two condyles of the occipital bone and superior articular depressions of the C1 vertebra. The articulating surfaces form a combined condylar biaxial joint.

Each bone connection has separate capsules, and ligaments fix them outside:

• The anterior membrane, which is stretched between the anterior arch of C1 and the occipital bone.
• The posterior membrane, which is located in the area between the posterior arch of the atlas, as well as the posterior circumference of the opening in the occipital bone of the skull.

Reference. The articulating surfaces are enclosed in separate capsules, but they move simultaneously.

The human atlantooccipital node allows movement around the frontal and sagittal axes. Around the first, you can tilt your head back and forth, and around the second - tilt it to the right and left. The anterior end of the sagittal axis is slightly higher than the posterior one. Due to the diagonal arrangement of the axis, with a lateral tilt, the head turns slightly in the opposite direction.

The muscles and ligaments of the atlanto-occipital node allow you to move the head relative to the neck, fix the back of the head, the skull in the desired position. The ligamentous nodes hold the tooth-like bone in a constant position when the head rotates, protecting the spinal cord and blood vessels from damage. At the junction of the skull with the cervical spine, movements with a small amplitude are possible, wider movements are possible with the participation of the entire neck.

As mentioned earlier, C1 has a wide spinal foramen, which allows the upper spinal cord to function normally. On the back surface of the atlantooccipital node passes the vertebral artery, as well as a large number of spinal nerves that transmit signals from the central nervous system.

If there is a violation of blood circulation in the area of ​​\u200b\u200bthe atlanto-occipital joint, people feel the following symptoms:

• Headaches, migraines.
• Increase in blood pressure.
• Frequent nausea, vertigo (dizziness), occasional vomiting.
• Loss of consciousness.
• Hearing and vision disorders, etc.

When the blood supply is disturbed, the brain suffers from a lack of nutrients, oxygen. In this case, medical treatment is necessary.

Atlas displacement

Causes and symptoms

One of the most common pathologies of the cervical spine is the displacement of the atlas relative to the C2 axis. Then the functionality of the upper cervical zone is disturbed as a result of compression of the nerve roots, as well as blood vessels, and this leads to many pathologies.

When the very first vertebra of the cervical segment is displaced, then the work of important regulatory departments of the central nervous system is disrupted. If the bulb of the brain is damaged, respiratory movements and the work of the heart may stop, since this area contains important nerve centers.

Reference. With subluxation of the atlas, headaches appear in almost all patients, the spine is deformed. Some patients experience pain in the upper and lower extremities, the abdomen, osteochondrosis develops, intervertebral hernia, dizziness, etc. After the vertebra is repositioned, all unpleasant symptoms disappear.

Atlas can be displaced as a result of Kimmerli's anomaly - this is a congenital pathology in which an additional bone arch in the form of a semicircle is formed in the cervical region. But most often, subluxation can be provoked by the following factors:

• Diseases of the spinal column, for example, osteochondrosis, kyphosis, spondylosis.
• Injury during childbirth, admitted as a result of inaccurate actions of the obstetrician.
• Spondylolysis - non-union of the vertebral arch in the area between the joints or the legs of the arch, which occurs due to a delay in the development of the posterior part of the spinal column.
• Sports injuries, falls, accidents, etc.

The displacement of the atlas is a pathology that has a hidden course, so for a long time, patients are not even aware of their condition. However, the disease can be identified by the following symptoms:

• Severe and long-lasting headache.
• There are disorders of hearing, vision.
• The blood supply to the brain is interrupted.
• Memory worsens.
• The sensitivity of the hands is disturbed, which is manifested by tingling, a feeling of "crawling", numbness.
• Weakening of the muscles of the neck to such an extent that the patient cannot hold his head.
• There is pain in the back of the head or neck.
• Sleep disorders occur.
• The mucous membrane of the mouth dries up.
• Breathing is disturbed.
• There are coughing fits for no apparent reason, the voice changes.

Reference. After injury to the cervical spine, an urgent need to visit a doctor, even if there are no suspicious symptoms.

If the atlas subluxation is not treated, the work of the nervous system, the vasomotor center is disrupted, which causes the brain to suffer, and the risk of autonomic dysfunction increases. When C1 is displaced, cerebrospinal fluid accumulates in the spinal canal, as a result, the functions of the spine and spinal cord are impaired. There is also a risk of vascular compression, then nausea, vomiting may occur, and the likelihood of disruption of the nervous, mental, and hormonal systems increases.

As you can see, the atlas is the most important vertebra that is involved in the work of many organs and systems. Therefore, when it is displaced, their normal operation is disrupted.

Treatment of atlas displacement

If symptoms of atlas displacement appear, you need to contact a traumatologist. To detect pathology, palpation, radiography, and functional tests are performed. A CT or MRI may also be needed.

It is important to set the displaced vertebra, but only an experienced specialist should do this, since there is a risk of injury to blood vessels and nerves. Then the patient may remain disabled or die.

After the atlas is repositioned, the patient must wear a special collar for several months. To stop severe pain, painkillers, anesthetics (Novocaine) are used, in severe cases, glucocorticosteroids cannot be dispensed with. Muscle relaxants will help relax spasmodic muscles, avoid paralysis.

Comprehensive and timely therapy will help speed up recovery, as well as prevent dangerous complications.

Main conclusions

Atlas is the most important vertebra of the cervical segment of the spine. Due to its special structure, C1 is able to hold its head and perform various neck movements. However, due to its excessive mobility, the atlas is often damaged. Displacement of the first vertebra is one of the most common pathologies of the cervical region. When the first symptoms of atlas subluxation appear, you should immediately visit a doctor, otherwise the risk of dangerous complications increases, up to paralysis or death of a person.