The spine is the axis on which the entire human body rests: internal organs and muscles. It consists of 33 or 34 vertebrae. The spine also consists of several vertebrae with no function. It is a tailbone - an ancestral remnant.
The spineis the support of the whole body. It supports the weight of the body and provides balance, acts as a grip for many bones, absorbs shocks and protects the spinal cordand spinal nerves.
Structure and functions of the spine
There are 7cervical vertebraeat the top (the smallest and most mobile, they allow the head to move in different directions). Below there are 12 thoracic vertebrae connected with 12 pairs of ribs: 10 pairs connect to the sternum, forming a chest that protects important organs and ensures easy breathing, then 5 lumbar vertebrae (they are the most loaded when sitting or standing) and 5 fused vertebrae form sacrum, which, together with the pelvis, covers the bladder and organs of the reproductive system. At the bottom, 4-5 fused vertebrae form the coccyx. They have no function, they are a remnant of the ancestors.
When the spine is relieved, such as when lying on the back, the intervertebral disc soaks up like a sponge. When we stand or sit, it gives the fluid back out. Therefore, in the morning we are 1 cm higher than in the evening. The lower growth and reduction of the spine elasticity in the elderly are explained, among others, by reduced water uptake capacity of the discs.
Each vertebra consists of a body, an arch and 3 processes: 2 transverse and 1 spinous. The transverse processes of adjacent vertebrae form joints, covered with cartilage and filled with synovial fluid, which reduces friction and causes the articular surfaces to glide smoothly, allowing bending, straightening, lateral and torsion movements of the entire spine.
Vertebrae arranged one on the other the second is a protective bone channel for the spinal cord. Nerve roots extend from it through the intervertebral holes. They branch more and more, creating a network that conducts impulses between the brain and the rest of the body. Nerves in the cervical spine are responsible for the hands, in the thoracic section for the torso, in the lumbar region for the legs.
The vertebrae are separated by intervertebral discs, commonly called disks. The disc is made of a fibrous ring that surrounds the filled nucleusjelly-like substance. It fulfills the function of a ball bearing, enabling movements between adjacent vertebrae.
The disc keeps the vertebrae at appropriate intervals, absorbs shocks, takes the pressure force and distributes it evenly over the entire surface, e.g. when we are sitting. As a result, the circles do not collide and do not crush.
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