The vertebral disc is a thin piece of cartilage located in between all of the spinal vertebrae, except the top two cervical vertebrae. The discs act as shock absorb-er against the compressible loads placed on our spines. Spinal discs are composed of two main parts: the outer layer made up of strong circular fibers (picture a birds nest), and a softer fluid filled interior (picture a jelly doughnut). As we age, our vertebral discs lose some of the fluid that helps them maintain flexibility. This is a natural process called disc degeneration. Disc herniations often result from injuries to the spine, which can cause tiny tears or cracks in the outer layer of the disc. The softer, fluid filled interior of the disc can be forced out through the tears or cracks in the capsule, which causes the disc to bulge (known as a protrusion), break open (prolapse), or break into fragments (sequestration).
Injury to the disc can occur from:
- A sudden heavy strain or increased pressure to the lower back. Sometimes a sudden twisting movement or even a sneeze will force the disc to herniate or rupture.
- Activities that are done over and over again that may stress the lower back including poor lifting habits, bad posture, or sports-related injuries.