In their function as shock absorbers, intervertebral discs are constantly being compressed. If you press the simulator straight up and down, the pressure is the same throughout the disc and it becomes homogeneously deformed.
Only if the disc was previously damaged, with injured ligaments, a high pressure might cause a protusion.
However, if you press the front part of the simulator, the nucleus of the disc moves to the other side and a protusion or a slipped disc is formed. This movement also may simulate sciatica.
The picture shows the formation of a poster lateral hernia, one of the most usual.
Also a hernia may occur when you turn the vertebras. When the ligaments of the disc are turned, the pressure inside the disc becomes very strong and a protrusion occurs in the weakness area.
That movement simulates disc torsion in a turn of the spine.
Finally, if you press the front part and turn the vertebras at the same time, a big hernia is formed.
This is a very risky movement, especially for people that usually suffer from back pain.
Ferran García Modrego (Barcelona, 1973) is physiotherapist and expert in Ergonomics and Work Risk Prevention.
Awared of the necessity of taking care of our posture so as to prevent back pain, Ferran created and developed this vertebral simulator in order to show the injure mechanism of a intervertebral disc in a visual and simple way.