Intervertebral Disc

The human spine consists of bony parts, the vertebrae, and cartilage parts, the discs. The combination of fixed and flexible elements (vertebrae and discs) gives the spine the quality of a flexible stick with both a supportive function and the possibility of movement. The cooperation of diverse back and stomach muscles plays an important role here.

structure and function  of the intervertebral disc

Each disc is surrounded by two vertebrae, building the functional unit of the intervertebral joint. It consists of cartilage and can be separated into two parts: an outer fibrous ring (anulus fibrosus) and an inner jelly-like nucleus (nucleus pulposus).

The function of the disc is on the one hand to enable the movement between two vertebrae and on the other hand the transmission of weight from one vertebra to the other. Due to its high water content, the nucleus pulposus cannot be pressed together. Under pressure it distributes the pressure to all sides onto the outer fibrous anulus fibrosus, which in turn puts traction forces against the pressure of the nucleus pulposus. So, the disc acts as a shock absorber: sudden pressure results in an instant expansion of the anulus. By this mechanism, the adjacent vertebrae are saved from harmful congestion.