The intervertebral disks are between the bodies of the vertebrae of the vertebral column. They act as a buffer like the shock absorber of a car and cushion compression and shocks for the vertebral column (columna vertebralis). When we stand, we place a burden on the vertebral column, and the intervertebral disks are pressed together. If we lie down, they take on their original form again. Their elasticity decreases in the course of life because of a loss of water content.
Intervertebral disks consist of a tight fibrous ring (anulus fibrosus) and a gellintanoid nucleus (nucleus pulposus). The fibrous ring consists of concentrically arranged collangenous fibers and fibrous cartilage that keep the gellintanoid nucleus tense. The gellintanoid nucleus moves within the intervertebral disk, depending on how much the vertebral column bends and stretches. The thickness of the intervertebral disks increases altogether from the head end (cranial) downwards (caudal).
The intervertebral disks are connected with the neighboring bodies of the vertebrae (corpus vertebrae) through hyaline cartilage. In addition, they are secured by the front and rear longitudinal ligament (ligamenta longitudinalia). The surface of the rear longitudinal ligament (ligamentum longitudinale posterius) grows together with vertebral disks, although the front longitudinal ligament (ligamentum longitudinale anterius) is only loosely connected with them.
The intervertebral disks form a functional unit together with the longitudinal ligaments. This is why they are termed symphysis intervertebralis.
Please click on the image below for a brief movie on the intervertebral disc.
