The vertebral column, or spine, can be broken down into three main sections:
- the cervical spine allows us to move our head around,
- the thoracic spine works with the ribs to play an important role in breathing, in particular,
- the lumbar spine is mainly used for the flexion and extension of the torso.
Vertebrae are separated from each other by intervertebral disks made of a fibrous ring surrounding a viscous nucleus. These disks act as shock-absorbers. The loads borne by these disks vary greatly according to the position and the effort made:
25 kg - 50 kg - 140 kg - 150 kg - 200 kg - 300 kg
The effects of stress are also concentrated on the spine.