The intervertebral discs are located between each vertebrae in the spinal column. Of the vertebrae, there are 7 cervical (neck), 12 thoracic (mid-back) and 5 lumbar (low back) discs. The discs make up approximately 1/3 of the spinal column. They have three main functions: (1) "Absorb shock" from everyday wear and tear. (2) Allow movement of our spinal column. (3) Separating the vertebrae.
The intervertebral disc is actually a type of cartilaginous joint. Discs consist of an outer layer, annulus fibrosis, and an inner nucleus pulposus, which is a soft, jelly-like, substance. The disc is made up of proteins called collagen and proteoglycans that attract water. Normally, discs compress when pressure is put on them and decompress when the pressure is relieved. These discs do not have a blood supply; therefore, they exchange nutrients by a process called "imbibition". Imagine a sponge filled with water; when that sponge is compressed, the water is forced out of the sponge. When the compressive force is removed, the water is "sucked" back into the sponge. This is precisely how discs stay healthy and functional. Diseased discs can lead to degenerative disc disease that can then lead to: arthritis, herniated discs, bulging discs, facet syndromes, sciatica and spinal stenosis.For more info in discs and disc injuries, visit http://www.montcochiro.com/3D_spine/ and click on degeneration to watch the video.