The verterbral column

Synonyms in further meaning

Movable axle skeleton of the body, columna vertebralis, spinal or vertebral column

German: Wirbelsäule

Definition

The vertebral column (medicinal: columna vertebralis) describes the movable axle skeleton of the body. The vertebral column supports the body and, thus, is the constructional element of all vertebrae which carries their trunk and the upper limbs. Moreover it distinguishes itself by its extensive moving possibilities. A so-called physiological S-bend can be found.

The vertebral column consists of the vertebrae, the intervertebral discs and supporting ligaments whose function it is to connect and stabilise the structures of the vertebral column. The human vertebral column consists of 33 – 34 vertebral bodies that are differentiated according to their functions.

Thus we differentiate between 7 cervical vertebrae of the so-called cervical vertebral column, 12 thoracic vertebrae of the so-called thoracic vertebral column, 5 lumbar vertebrae of the lumbar vertebral column, 5 sacrum and coccyx vertebrae. The two last mentioned types of vertebrae merge into the sacrum-coccyx at the age of 20 to 25 years.

The vertebral column forms the so-called vertebral channel which contains the spinal marrow or cord.

STRUCTURE OF THE VERTEBRAL COLUMN

Anatomy

STRUCTURE OF THE VERTEBRAL COLUMN

The vertebral column consists of altogether 32-33 vertebrae, is, thus, assembled of 7 cervical vertebrae of the so-called cervical vertebral column, 12 thoracic vertebrae of the so-called thoracic vertebral column, 5 lumbar vertebrae of the lumbar vertebral column and 5 sacrum and coccyx vertebrae.

Between the vertebrae there are buffers (=inter-vertebral discs), whose main job is to absorb heavy movements. Together with the buffers the vertebrae form an elastic column.

To achieve the full flexibility the combination with muscles and ligaments is required, however.

Construction of the vertebrae

Independent of size and localisation the vertebrae do not vary in their basic looks. Wherever they are located, all vertebrae consist of:

• A body (corpus)
• The arch (arcus) that connects to the body, and the so-called processes that transform the power of the muscles to the body of the vertebrae and also to the processes
• The channel that developed due to the physiological bend and contains the spinal chord

CT picture: vertebral column with vertebral body sidewise process joint process / vertebral joint thorn process vertebral hole

In general we can state that the vertebrae are very close to each other and in direct neighbourhood to each other. They are only separated by the inter-vertebral disc. In between the vertebral body and the inter-vertebral disc we find the inter-vertebral hole which enables spinal nerves to exit and, thus, regulate the sensory and motor periphery.

All vertebral bodies do not only support the upright walk of the human, but also build red corpuscles – like the tubular bones of the body.

The cervical vertebral column (CVC)

The cervical vertebral column consists of 7 cervical vertebrae, which provide the head with an extremely high mobility. The first and the second cervical vertebrae differ very much from the remaining five in the way they look. This is due to their function: the first cervical vertebra (atlas) is circular and carries the head. The second cervical vertebra (axis) builds the so-called atlanto-axial-joint together with the first cervical vertebra (axis), which does not only provide the head with its mobility, but also the whole cervical vertebral column.

In addition to this the second cervical vertebra (axis) has a so-called tooth (dens) that penetrates the first cervical vertebra and carries the head together with the first cervical vertebra.

If the head is turned to the side, the ring of the atlas moves around the tooth of the axis.

The thoracic vertebral column (TVC)

To the 12 thoracic vertebrae of the thoracic vertebral column the rips are attached. Herewith the thoracic vertebrae and each of the attaching pairs of rips are connected through a joint with the joint area of the corresponding sidewise process. In the front however all pairs of rips with the exception of the lower two join the breastbone (=sternum).

Within the context of explaining the vertebral column (structure of the vertebral column) we have already hinted at the fact that on both sides (right and left) between vertebral body and inter-vertebral disc there is a so-called inter-vertebral hole, which allows the spinal nerves to exit the spinal channel.

This is the only way to secure sensory and motor in the body. Which parts are aimed at depends on the localisation:

For example through the inter-vertebral hole in the lower part of the thoracic vertebral column spinal nerves exit who head for sensory and motor in the legs. Injuries in this part of the thoracic vertebral column usually implicate a sensation of numbness and paralysis in the corresponding part of the leg.

The lumbar vertebral column (LVC)

The lumbar vertebral column consists of the 5 lumbar vertebrae of the vertebral column. They have to carry the most weight, because they are located in the lower part of the vertebral column. That is also the reason why they are much thicker than the other vertebrae. However this does not secure against the signs of wear and tear that are especially common in this area. Thus wear and tear of the joints and prolapsed inter-vertebral discs happen most often in the region of the lumbar vertebral column.

The lumbar vertebral column also differs from the other parts of the vertebral column regarding its structure. For example there is no spinal chord from the second lumbar vertebra on. That means: nerves for sensory and motor in the region of the legs and the pelvis fill the vertebral channel in this area. This special area in which the spinal chord ends and is then filled with nerves is called pony-tail (medicinal: cauda equina).

x-ray picture of lumbar vertebral column: inter-vertebral disc (blue) vertebral body sacrum (red)

Sacrum and coccyx

Between the 20th and 25th year the 5 sacrum vertebrae, the inter-vertebral discs and the corresponding rudimentary rips merge. They then form the so-called sacrum (os sacrum). The same happens with the 4 coccyx vertebrae. They then from the coccyx (os coccyges), on which the muscles and ligaments of the pelvic area insert.

The newly formed sacrum (os sacrum) is not only a very important part of the vertebral column. Moreover it forms the so-called ileo-sacrum-joint together with the coccyx; thus it also forms an important part of the pelvis by joining the vertebral column with the pelvis.

Intervertebral disc

An intervertebral disc is the cartilaginous connection between two vertebral bodies. It consists of an outer ring made of connective tissue and cartilage, the so-called annulus fibrosus, and a soft jelly-like inner nucleus, which is called nucleus pulposus.

Picture of intervertebral disc: nucleus pulposus annulus fibrosus

The inter-vertebral disc functions as buffer and, thus, absorbs the bumps and vibrations that affect the vertebral column. In addition to that it enables a better mobility between the individual vertebrae. Not all vertebrae have such a buffer: the first and second cervical vertebrae form a special joint and as such have a different structure. The same applies to the sacrum-coccyx vertebrae that merge during the physical development (see: sacrum-coccyx further above).

Due to the important functions that are assigned to the inter-vertebral disc, it is understandable that we have to show a high grade of responsibility to it. That means: defects to the vertebral column have to be avoided by all means. This can be achieved for example by appropriate behaviour of the back (so-called dorsal school).

Furthermore it is important that the inter-vertebral disc is fed correctly. The right food has nothing to do with healthy eating in principal. The mobility and flexibility of the inter-vertebral disc is achieved by regular consumption of fluid which can only be achieved by regular and sufficient exercise of the human. If the inter-vertebral disc is strained and relieved in an adequate alternation, a sufficient reception of fluid is guaranteed by working it into the inter-vertebral disc.

Nothing is as important for sustaining the flexibility of the inter-vertebral disc as exercise. This exercise, however, has to be adequate. That means that constant exercise with little breaks can be as damaging as a chronic lack of exercise.

In both cases the outer ring can become brittle and cracked. That then enables the inner jelly-like nucleus to outflow and possible cause a prolapsed intervertebral disc.

In order to give the vertebral column a maximum of strengthening as well as a maximum of flexibility, it takes strong ligaments that stretch out over the whole length of the vertebral column as well as additional ligaments which will be introduced in the further process.

• The front lengthwise ligament is responsible for the stabilisation between the stomach region and the vertebral column
• The back lengthwise ligament stretches out over the back vertebral body areas and lines the vertebral channel
• The yellow ligament (ligamentum flavum) is situated between the adjoining vertebral arches
• A system of ligaments connects the sidewise processes of the vertebrae with the inter-sidewise processes
• A system of ligaments (inter-thorn-process ligaments) connects the thorn processes with each other and, thus, the back of the vertebrae
• One ligament also stretches over all thorn-processes and, thus, strengthens the vertebral column in the form of a back stabilisation

The dorsal muscles strengthen the system of ligaments additionally. Only the joined effect and mutual support enable the known flexible and stabilising function of the vertebral column and, thus, make the multiple movement possibilities in all directions possible including eventual rotations.