Dynamics of the human vertebral column

The skeleton of the spinal column serves as a solid support for the body and consists of 33-34 vertebrae. A vertebra consists of two parts - the vertebral body (in front) and the vertebral arch (in back). The vertebral body accounts for the bulk of the vertebra. The vertebral arch consists of four segments. Two of them are the pedicles, which form the supporting walls. The other two parts are thin plates, which form a kind of "roof". Three bone processes extend from the vertebral arch. The right and left transverse processes branch off from each "pedicle-plate" joint. In addition, on the midline, when a person bends forward, you can see a spinous process protruding backward. Depending on the location and function, the vertebrae of different sections have specific structural features, and the direction and degree of movement of the vertebra are determined by the orientation of the articular processes.

Cervical vertebrae. The articular processes are flat and oval in shape and are located in space at an angle of 10-15° to the frontal plane, 45° to the sagittal plane, and 45° to the horizontal plane. Thus, any displacement produced by the joint located above relative to the lower one will occur at an angle to three planes simultaneously. The vertebral body has a concavity of the upper and lower surfaces and is considered by many authors to be a factor that contributes to an increase in the range of motion.

Thoracic vertebrae. The articular processes are inclined to the frontal plane at an angle of 20°, to the sagittal plane at an angle of 60°, to the horizontal and frontal plane at an angle of 20°.

Such spatial arrangement of joints facilitates displacement of the superior joint relative to the inferior joint simultaneously ventrocranially or dorsocaudally in combination with its medial or lateral displacement. The articular surfaces have a predominant slope in the sagittal plane.

Lumbar vertebrae. The spatial arrangement of their articular surfaces differs from that of the thoracic and cervical spines. They are arched and positioned at an angle of 45° to the frontal plane, at an angle of 45° to the horizontal plane, and at an angle of 45° to the sagittal plane. This spatial arrangement facilitates the displacement of the superior joint relative to the inferior joint, both dorsolaterally and ventromedially, in combination with cranial or caudal displacement.

The important role of intervertebral joints in the movement of the spine is also evidenced by the well-known works of Lesgaft (1951), in which much attention is paid to the coincidence of the centers of gravity of the spherical surface of the joints in segments C5-C7. This explains the predominant volume of motion in them. In addition, the inclination of the articular surfaces simultaneously to the frontal, horizontal and vertical planes promotes simultaneous linear motion in each of these three planes, excluding the possibility of single-plane motion. In addition, the shape of the articular surfaces promotes sliding of one joint along the plane of another, limiting the possibility of simultaneous angular motion. These ideas are consistent with the studies of White (1978), as a result of which, after removal of the articular processes with arches, the volume of angular motion in the vertebral motion segment increased in the sagittal plane by 20-80%, the frontal plane by 7-50%, and the horizontal plane by 22-60%. The radiographic data of Jirout (1973) confirm these results.

The spinal column contains all types of bone connections: continuous (syndesmoses, synchondroses, synostoses) and discontinuous (joints between the spinal column and the skull). The bodies of the vertebrae are connected to each other by intervertebral discs, which together make up approximately 'A of the entire length of the spinal column. They primarily function as hydraulic shock absorbers.

It is known that the amount of mobility in any part of the spinal column largely depends on the ratio of the height of the intervertebral discs and the bony part of the spinal column.

According to Kapandji (1987), this ratio determines the mobility of a particular segment of the spinal column: the higher the ratio, the greater the mobility. The cervical spine has the greatest mobility, since the ratio is 2:5, or 40%. The lumbar spine is less mobile (ratio 1:3, or 33%). The thoracic spine is even less mobile (ratio 1:5, or 20%).

Each disc is constructed in such a way that it has a gelatinous core and a fibrous ring inside.

The gelatinous core consists of a non-compressible gel-like material enclosed in an elastic "container". Its chemical composition is represented by proteins and polysaccharides. The core is characterized by strong hydrophilicity, i.e. attraction to water.

According to Puschel (1930), at birth the fluid content in the nucleus is 88%. With age, the nucleus loses its ability to bind water. By the age of 70, its water content is reduced to 66%. The causes and consequences of this dehydration are of great importance. The reduction in water content in the disc can be explained by a decrease in the concentration of protein, polysaccharide, and also by a gradual replacement of the gel-like material of the nucleus with fibrous cartilaginous tissue. The results of studies by Adams et al. (1976) showed that with age there is a change in the molecular size of proteoglycans in the nucleus pulposus and the fibrous ring. The fluid content decreases. By the age of 20, the vascular supply of the discs disappears. By the age of 30, the disc is nourished exclusively by lymph diffusion through the end plates of the vertebrae. This explains the loss of flexibility of the spinal column with age, as well as the impaired ability of the elderly to restore the elasticity of an injured disc.

The nucleus pulposus receives the vertical forces acting on the vertebral body and distributes them radially in the horizontal plane. To better understand this mechanism, one can imagine the nucleus as a mobile hinge joint.

The annulus fibrosus is made up of approximately 20 concentric layers of fibers, intertwined so that one layer is at an angle to the previous one. This structure provides control of movement. For example, under shear stress, oblique fibers running in one direction tense up, while those running in the opposite direction relax.

Functions of the nucleus pulposus (Alter, 2001)

Action	Bending	Extension	Lateral flexion
The upper vertebra is lifted	Front	Back	Towards the bending side
Therefore, the disk is straightened.	Front	Back	Towards the bending side
Therefore, the disk increases	Back	Front	To the side opposite to the bend
Therefore, the core is directed	Forward	Back	To the side opposite to the bend

The fibrous ring loses its elasticity and flexibility with age. In youth, the fibroelastic tissue of the ring is predominantly elastic. With age or after injury, the percentage of fibrous elements increases and the disc loses elasticity. As elasticity is lost, it becomes more susceptible to injury and damage.

Each intervertebral disc can shorten in height by an average of 1 mm under a 250 kg load, which for the entire spinal column results in a shortening of approximately 24 mm. At a 150 kg load, the shortening of the intervertebral disc between T6 and T7 is 0.45 mm, and a 200 kg load causes a shortening of the disc between T11 and T12 by 1.15 mm.

These changes in the discs from pressure disappear quite quickly. When lying down for half an hour, the body length of a person with a height of 170 to 180 cm increases by 0.44 cm. The difference in the body length of the same person in the morning and evening is determined on average by 2 cm. According to Leatt, Reilly, Troup (1986), a decrease in height by 38.4% was observed in the first 1.5 hours after waking up and by 60.8% in the first 2.5 hours after waking up. Restoration of height by 68% occurred in the first half of the night.

In an analysis of the difference in height between children in the morning and afternoon, Strickland and Shearin (1972) found a mean difference of 1.54 cm, with a range of 0.8–2.8 cm.

During sleep, the load on the spine is minimal and the discs swell, absorbing fluid from the tissues. Adams, Dolan and Hatton (1987) identified three significant consequences of daily variations in the load on the lumbar spine: 1 - "swelling" causes increased stiffness of the spine during lumbar flexion after awakening; 2 - early in the morning, the ligaments of the discs of the spine are characterized by a higher risk of injury; 3 - the range of motion of the spine increases towards the middle of the day. The difference in body length is due not only to a decrease in the thickness of the intervertebral discs, but also to a change in the height of the arch of the foot and perhaps also to some extent to a change in the thickness of the cartilage of the joints of the lower extremities.

Discs can change their shape under the influence of force effects before a person reaches puberty. By this time, the thickness and shape of the discs are finally determined, and the configuration of the spinal column and the associated type of posture become permanent. However, precisely because posture depends primarily on the characteristics of the intervertebral discs, it is not a completely stable feature and can change to some extent under the influence of external and internal force effects, in particular physical exercise, especially at a young age.

Ligamentous structures and other connective tissues play an important role in determining the dynamic properties of the spinal column. Their task is to limit or modify the movement of the joint.

The anterior and posterior longitudinal ligaments run along the anterior and posterior surfaces of the vertebral bodies and intervertebral discs.

Between the arches of the vertebrae are very strong ligaments consisting of elastic fibers, which give them a yellow color, due to which the ligaments themselves are called interarch or yellow. When the spinal column moves, especially when bending, these ligaments stretch and become tense.

Between the spinous processes of the vertebrae are the interspinous ligaments, and between the transverse processes are the intertransverse ligaments. Above the spinous processes along the entire length of the spinal column runs the supraspinous ligament, which, approaching the skull, increases in the sagittal direction and is called the nuchal ligament. In humans, this ligament has the appearance of a wide plate, forming a kind of partition between the right and left muscle groups of the nuchal region. The articular processes of the vertebrae are connected to each other by joints, which in the upper parts of the spinal column have a flat shape, and in the lower, in particular in the lumbar region, they are cylindrical.

The connection between the occipital bone and the atlas has its own characteristics. Here, as between the articular processes of the vertebrae, there is a combined joint consisting of two anatomically separate joints. The shape of the articular surfaces of the atlanto-occipital joint is elliptical or ovoid.

Three joints between the atlas and the epistropheus are combined into a combined atlantoaxial joint with one vertical axis of rotation; of these, the unpaired joint is the cylindrical joint between the dens of the epistropheus and the anterior arch of the atlas, and the paired joint is the flat joint between the lower articular surface of the atlas and the upper articular surface of the epistropheus.

Two joints, the atlanto-occipital and atlanto-axial, located above and below the atlas, complement each other to form connections that provide the head with mobility around three mutually perpendicular axes of rotation. Both of these joints can be combined into one combined joint. When the head rotates around a vertical axis, the atlas moves together with the occipital bone, playing the role of a kind of intercalary meniscus between the skull and the rest of the spinal column. A rather complex ligamentous apparatus takes part in strengthening these joints, which includes the cruciate and pterygoid ligaments. In turn, the cruciate ligament consists of the transverse ligament and two legs - upper and lower. The transverse ligament passes behind the odontoid epistropheus and strengthens the position of this tooth in its place, being stretched between the right and left lateral masses of the atlas. The upper and lower legs extend from the transverse ligament. Of these, the upper one is attached to the occipital bone, and the lower one to the body of the second cervical vertebra. The pterygoid ligaments, right and left, go from the lateral surfaces of the tooth upward and outward, attaching to the occipital bone. Between the atlas and the occipital bone there are two membranes - the front and back, closing the opening between these bones.

The sacrum is connected to the coccyx by a synchondrosis, in which the coccyx can move mainly in the anteroposterior direction. The range of mobility of the apex of the coccyx in this direction in women is approximately 2 cm. The ligamentous apparatus also takes part in strengthening this synchondrosis.

Because the spinal column of an adult forms two lordotic (cervical and lumbar) and two kyphotic (thoracic and sacrococcygeal) curves, the vertical line emanating from the body's center of gravity intersects it in only two places, most often at the level of the C8 and L5 vertebrae. These ratios, however, may vary depending on the characteristics of a person's posture.

The weight of the upper half of the body not only puts pressure on the vertebrae, but also acts on some of them in the form of a force that forms the curves of the spinal column. In the thoracic region, the line of gravity of the body passes in front of the vertebral bodies, due to which there is a force effect aimed at increasing the kyphotic curve of the spinal column. This is prevented by its ligamentous apparatus, in particular, the posterior longitudinal ligament, the interosseous ligaments, as well as the tone of the extensor muscles of the trunk.

In the lumbar spine, the relationship is reversed, the line of gravity of the body usually passes in such a way that gravity tends to reduce the lumbar lordosis. With age, both the resistance of the ligamentous apparatus and the tone of the extensor muscles decrease, due to which, under the influence of gravity, the spine most often changes its configuration and forms one general bend directed forward.

It has been established that the forward shift of the center of gravity of the upper half of the body occurs under the influence of a number of factors: the mass of the head and shoulder girdle, upper limbs, chest, thoracic and abdominal organs.

The frontal plane, in which the body's center of gravity is located, deviates forward from the atlanto-occipital joint relatively little in adults. In young children, the mass of the head is of great importance because its ratio to the mass of the entire body is more significant, so the frontal plane of the head's center of gravity is usually more displaced forward. The mass of the upper limbs of a person to a certain extent affects the formation of the curvature of the spinal column depending on the displacement of the shoulder girdle forward or backward, since specialists have noticed some correlation between stooping and the degree of forward displacement of the shoulder girdle and upper limbs. However, with a straightened posture, the shoulder girdle is usually displaced backward. The mass of the human chest affects the forward displacement of the trunk's center of gravity the more its anteroposterior diameter is developed. With a flat chest, its center of mass is located relatively close to the spinal column. The chest organs and especially the heart not only contribute to the forward displacement of the center of mass of the trunk with their mass, but also act as a direct pull on the cranial part of the thoracic spine, thereby increasing its kyphotic bend. The weight of the abdominal organs varies depending on the age and constitution of the person.

The morphological features of the spinal column determine its compressive and tensile strength. There are indications in the specialized literature that it can withstand a compressive pressure of about 350 kg. The compressive resistance for the cervical region is approximately 50 kg, for the thoracic region - 75 kg and for the lumbar region - 125 kg. It is known that the tensile resistance is about 113 kg for the cervical region, 210 kg for the thoracic region and 410 kg for the lumbar region. The joints between the 5th lumbar vertebra and the sacrum are torn under a pull of 262 kg.

The strength of individual vertebrae to compression of the cervical spine is approximately as follows: C3 - 150 kg, C4 - 150 kg, C5 - 190 kg, C6 - 170 kg, C7 - 170 kg.

The following indicators are typical for the thoracic region: T1 - 200 kg, T5 -200 kg, T3 - 190 kg, T4 - 210 kg, T5 - 210 kg, T6 - 220 kg, T7 - 250 kg, T8 - 250 kg, T9 - 320 kg, T10 - 360 kg, T11 - 400 kg, T12 - 375 kg. The lumbar region can withstand approximately the following loads: L1 - 400 kg, L2 - 425 kg, L3 - 350 kg, L4 - 400 kg, L5 - 425 kg.

The following types of movements are possible between the bodies of two adjacent vertebrae. Movements along the vertical axis as a result of compression and stretching of the intervertebral discs. These movements are very limited, since compression is possible only within the elasticity of the intervertebral discs, and stretching is inhibited by longitudinal ligaments. For the spinal column as a whole, the limits of compression and stretching are insignificant.

Movements between the bodies of two adjacent vertebrae may occur partly in the form of rotation around a vertical axis. This movement is inhibited mainly by the tension of the concentric fibers of the fibrous ring of the intervertebral disc.

Rotations around the frontal axis are also possible between the vertebrae during flexion and extension. During these movements, the shape of the intervertebral disc changes. During flexion, its anterior part is compressed and the posterior part is stretched; during extension, the opposite phenomenon is observed. In this case, the gelatinous nucleus changes its position. During flexion, it moves backward, and during extension, it moves forward, i.e., toward the stretched part of the fibrous ring.

Another distinct type of movement is rotation around the sagittal axis, which results in a lateral tilt of the trunk. In this case, one lateral surface of the disc is compressed, while the other is stretched, and the gelatinous nucleus moves toward the stretch, i.e. toward the convexity.

The movements that occur in the joints between two adjacent vertebrae depend on the shape of the articular surfaces, which are located differently in different parts of the spinal column.

The cervical region is the most mobile. In this region, the articular processes have flat articular surfaces directed backwards at an angle of approximately 45-65°. This type of articulation provides three degrees of freedom, namely: flexion-extension movements are possible in the frontal plane, lateral movements in the sagittal plane, and rotational movements in the horizontal plane.

In the space between the C2 and C3 vertebrae the range of motion is somewhat smaller than between the other vertebrae. This is explained by the fact that the intervertebral disc between these two vertebrae is very thin and that the anterior part of the lower edge of the epistropheum forms a protrusion that limits motion. The range of flexion-extension motion in the cervical spine is approximately 90°. The forward convexity formed by the anterior contour of the cervical spine changes into concavity during flexion. The concavity thus formed has a radius of 16.5 cm. If radii are drawn from the anterior and posterior ends of this concavity, an angle open backwards equal to 44° is obtained. With maximum extension, an angle open forward and upwards equal to 124° is formed. The chords of these two arcs join at an angle of 99°. The greatest range of motion is observed between the C3, C4 and C5 vertebrae, somewhat less between C6 and C7 and even less between the C7 and T1 vertebrae.

Lateral movements between the bodies of the first six cervical vertebrae also have a fairly large amplitude. Vertebra C... is significantly less mobile in this direction.

The saddle-shaped articular surfaces between the bodies of the cervical vertebrae do not favor torsional movements. In general, according to various authors, the amplitude of movements in the cervical region averages the following values: flexion - 90°, extension - 90°; lateral tilt - 30°, rotation to one side - 45°.

The atlanto-occipital joint and the joint between the atlas and the epistropheus have three degrees of freedom of movement. In the first of these, forward and backward tilts of the head are possible. In the second, rotation of the atlas around the odontoid process is possible, with the skull rotating together with the atlas. Forward tilt of the head at the joint between the skull and the atlas is possible only by 20°, backward tilt - by 30°. Backward movement is inhibited by the tension of the anterior and posterior atlanto-occipital membranes and occurs around the frontal axis passing behind the external auditory opening and immediately in front of the mammillary processes of the temporal bone. A degree of forward tilt of the skull greater than 20° and 30° backward is possible only together with the cervical spine. Forward tilt is possible until the chin touches the sternum. This degree of tilt is achieved only with active contraction of the muscles that flex the cervical spine and tilt the head onto the body. When the head is pulled forward by gravity, the chin usually does not touch the sternum because the head is held in place by the tension of the stretched muscles of the back of the neck and the nuchal ligament. The weight of the forward-tilting head acting on the first-class lever is not sufficient to overcome the passivity of the back muscles of the neck and the elasticity of the nuchal ligament. When the sternohyoid and geniohyoid muscles contract, their force, together with the weight of the head, causes a greater stretching of the muscles of the back of the neck and the nuchal ligament, causing the head to tilt forward until the chin touches the sternum.

The joint between the atlas and the osseous can rotate 30° to the right and left. Rotation in the joint between the atlas and the osseous is limited by the tension of the pterygoid ligaments, which originate on the lateral surfaces of the condyles of the occipital bone and attach to the lateral surfaces of the odontoid process.

Due to the fact that the lower surface of the cervical vertebrae is concave in the anteroposterior direction, movements between the vertebrae in the sagittal plane are possible. In the cervical region, the ligamentous apparatus is the least powerful, which also contributes to its mobility. The cervical region is significantly less exposed (compared to the thoracic and lumbar regions) to the action of compressive loads. It is the attachment point for a large number of muscles that determine the movements of the head, spinal column and shoulder girdle. On the neck, the dynamic action of muscle traction is relatively greater in comparison with the action of static loads. The cervical region is little exposed to deforming loads, since the surrounding muscles seem to protect it from excessive static effects. One of the characteristic features of the cervical region is that the flat surfaces of the articular processes in the vertical position of the body are at an angle of 45 °. When the head and neck are tilted forward, this angle increases to 90 °. In this position, the articular surfaces of the cervical vertebrae overlap each other in the horizontal direction and are fixed due to the action of the muscles. When the neck is bent, the action of the muscles is especially significant. However, a bent neck position is common for a person during work, since the organ of vision must control the movements of the hands. Many types of work, as well as reading a book, are usually carried out with the head and neck bent. Therefore, the muscles, in particular the back of the neck, have to work to keep the head in balance.

In the thoracic region, the articular processes also have flat articular surfaces, but they are oriented almost vertically and are located mainly in the frontal plane. With this arrangement of the processes, flexion and rotation movements are possible, and extension is limited. Lateral bending is carried out only within insignificant limits.

In the thoracic region, the mobility of the spinal column is the least, which is due to the small thickness of the intervertebral discs.

Mobility in the upper thoracic region (from the first to the seventh vertebra) is insignificant. It increases in the caudal direction. Lateral bending in the thoracic region is possible by approximately 100° to the right and somewhat less to the left. Rotational movements are limited by the position of the articular processes. The range of motion is quite significant: around the frontal axis it is 90°, extension - 45°, rotation - 80°.

In the lumbar region, the articular processes have articulating surfaces oriented almost in the sagittal plane, with their upper-inner articular surface concave and the lower-outer convex. This arrangement of the articular processes excludes the possibility of their mutual rotation, and movements are performed only in the sagittal and frontal planes. In this case, extension movement is possible within greater limits than flexion.

In the lumbar region, the degree of mobility between the different vertebrae is not the same. In all directions, it is greatest between the vertebrae L3 and L4, and between L4 and L5. The least mobility is observed between L2 and L3.

The mobility of the lumbar spine is characterized by the following parameters: flexion - 23°, extension - 90°, lateral tilt to each side - 35°, rotation - 50. The intervertebral space between L3 and L4 is characterized by the greatest mobility, which should be compared with the fact of the central position of the L3 vertebra. Indeed, this vertebra corresponds to the center of the abdominal region in men (in women, L3 is located somewhat more caudally). There are cases in which the sacrum in humans was located almost horizontally, and the lumbosacral angle decreased to 100-105°. Factors limiting movements in the lumbar spine are presented in Table 3.4.

In the frontal plane, flexion of the spine is possible mainly in the cervical and upper thoracic regions; extension occurs mainly in the cervical and lumbar regions, in the thoracic region these movements are insignificant. In the sagittal plane, the greatest mobility is noted in the cervical region; in the thoracic region it is insignificant and increases again in the lumbar part of the spine. Rotation is possible within large limits in the cervical region; in the caudal direction its amplitude decreases and is very insignificant in the lumbar region.

When studying the mobility of the spine as a whole, it makes no arithmetical sense to sum up the figures characterizing the amplitude of movements in different sections, since during movements of the entire free part of the spine (both on anatomical preparations and on living subjects), compensatory movements occur due to the curvature of the spinal column. In particular, dorsal flexion in one section can cause ventral extension in another. Therefore, it is advisable to supplement the study of the mobility of different sections with data on the mobility of the spinal column as a whole. When studying an isolated spinal column in this regard, a number of authors obtained the following data: flexion - 225 °, extension - 203 °, side tilt - 165 °, rotation - 125 °.

In the thoracic region, lateral flexion of the spinal column is possible only when the articular processes are located exactly in the frontal plane. However, they are tilted slightly forward. As a result, only those intervertebral joints whose facets are oriented approximately in the frontal plane participate in lateral tilt.

Rotational movements of the spinal column around the vertical axis are possible to the greatest extent in the neck area. The head and neck can be rotated relative to the trunk by approximately 60-70° in both directions (i.e., approximately 140° in total). Rotation is impossible in the thoracic spine. In the lumbar spine, it is practically zero. The greatest rotation is possible between the thoracic and lumbar spine in the area of the 17th and 18th biokinematic pairs.

The total rotational mobility of the spinal column as a whole is thus equal to 212° (132° for the head and neck and 80° for the 17th and 18th biokinematic pairs).

Of interest is the determination of the possible degree of rotation of the body around its vertical axis. When standing on one leg, rotation in the semi-flexed hip joint by 140° is possible; when supporting on both legs, the amplitude of this movement decreases to 30°. In total, this increases the rotational capacity of our body to approximately 250° when standing on two legs and to 365° when standing on one leg. Rotational movements performed from head to toe cause a decrease in body length by 1-2 cm. However, in some people this decrease is significantly greater.

The torsional movement of the spinal column is carried out at four levels, characteristic of different types of scoliotic curves. Each of these levels of twisting depends on the function of a certain muscle group. The lower level of rotation corresponds to the lower aperture (level of the 12th false ribs) of the thorax. The rotational movement at this level is due to the function of the internal oblique muscle of one side and the external oblique muscle of the opposite side, acting as synergists. This movement can be continued upwards due to the contraction of the internal intercostal muscles on one side and the external intercostal muscles on the other. The second level of rotational movements is at the shoulder girdle. If it is fixed, the rotation of the thorax and spinal column is due to the contraction of the anterior serratus and pectoral muscles. Rotation is also provided by some muscles of the back - the posterior serratus (upper and lower), iliocostalis and semispinalis. The sternocleidomastoid muscle, when contracting bilaterally, holds the head in a vertical position, throws it back, and also flexes the cervical spine. When contracting unilaterally, it tilts the head to its side and turns it to the opposite side. The splenius capitis muscle extends the cervical spine and turns the head to the same side. The splenius cervicis muscle extends the cervical spine and turns the neck to the side of contraction.

Side bends are often combined with its rotation, because the location of the intervertebral joints favors this. The movement is performed around an axis that is not located exactly in the sagittal direction, but is tilted forward and downward, as a result of which the side bend is accompanied by rotation of the trunk backward on the side where the convexity of the spinal column is formed during the bend. The combination of side bends with rotation is a very significant feature that explains some properties of scoliotic curves. In the area of the 17th and 18th biokinematic pairs, side bends of the spinal column are combined with its rotation to the convex or concave side. In this case, the following triad of movements is usually performed: side bend, forward bending, and rotation to the convexity. These three movements are usually realized with scoliotic curves.

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Functional muscle groups that provide movement of the spinal column

Cervical spine: movements around the frontal axis

Bending

1. Sternocleidomastoid muscle
2. Anterior scalene muscle
3. Posterior scalene muscle
4. Longus colli muscle
5. Longus capitis muscle
6. Rectus capitis anterior muscle
7. Subcutaneous muscle of the neck
8. Omohyoid muscle
9. sternohyoid muscle
10. Sternothyroid muscle
11. Thyrohyoid muscle
12. Digastric
13. Stylohyoid muscle
14. Mylohyoid muscle
15. Geniohyoid muscle

Movements around the sagittal axis

1. Longus colli muscle
2. Anterior scalene muscle
3. Middle scalene muscle
4. Posterior scalene muscle
5. Trapezius muscle
6. Sternocleidomastoid muscle
7. The erector spinae muscle
8. Strapon cervicalis muscle
9. Longus capitis muscle

Movements around the vertical axis - twisting

1. Anterior scalene muscle
2. Middle scalene muscle
3. Posterior scalene muscle
4. Sternocleidomastoid muscle
5. Upper trapezius muscle
6. Strapon cervicalis muscle
7. Levator scapulae muscle

Circular movements in the cervical spine (circumduction):

With the alternate participation of all muscle groups that produce flexion, tilt and extension of the spine in the cervical region.

Lumbar spine: movements around the frontal axis

Bending

1. Iliopsoas muscle
2. Quadratus lumborum muscle
3. Rectus abdominis muscle
4. External oblique muscle of the abdomen

Extension (thoracic and lumbar)

1. The erector spinae muscle
2. Transverse spinal muscle
3. Interspinous muscles
4. Intertransverse muscles
5. Muscles that raise the ribs
6. Trapezius muscle
7. Latissimus dorsi
8. Rhomboid major muscle
9. Rhomboid minor muscle
10. Serratus posterior superior muscle
11. Serratus posterior inferior muscle

Lateral flexion movements around the sagittal axis (thoracic and lumbar spine)

1. Intertransverse muscles
2. Muscles that raise the ribs
3. External oblique muscle of the abdomen
4. Internal oblique muscle of the abdomen
5. Transverse abdominal muscle
6. Rectus abdominis muscle
7. Quadratus lumborum muscle
8. Trapezius muscle
9. Latissimus dorsi
10. Rhomboid major muscle
11. Serratus posterior superior muscle
12. Serratus posterior inferior muscle
13. The erector spinae muscle
14. Transverse spinalis muscle

Movements around the vertical axis - twisting

1. Iliopsoas muscle
2. Muscles that raise the ribs
3. Quadratus lumborum muscle
4. External oblique muscle of the abdomen
5. Internal oblique muscle of the abdomen
6. External intercostal muscle
7. Internal intercostal muscle
8. Trapezius muscle
9. Rhomboid major muscle
10. Latissimus dorsi
11. Serratus posterior superior muscle
12. Serratus posterior inferior muscle
13. The erector spinae muscle
14. Transverse spinal muscle

Circular rotational movements with mixed axes (circumduction): with alternate contraction of all the muscles of the trunk, producing extension, pubic flexion and flexion of the spinal column.