Discs, (proper name, inter-vertebral discs) are structures located between the bones of the spine. These bones are called vertebrae. They protect the spinal cord. Nerves to most parts of the body leave the spinal cord and emerge through spaces between the vertebrae. Discs act as shock absorbers or cushions and prevent contact and friction between the vertebrae.
In scientific terms there is no such thing as a “slipped” disc. Discs are secured fast to a cartilage pad and then attached to the vertebral bones above and below. A slipped disc is simply a popular term for either a protruding (bulging) disc, or a ruptured (prolapsed) disc.
Normal Disc
Each disc is made up of two parts. An external ring – the annulus fibrosis – a tough substance which forms the outer two-thirds of the disc and the nucleus pulposis – a jelly like centre.
The front wall of the annulus is much thicker than the back, thanks mainly to supporting ligaments. This acts as a restraining force for the front portion of the disc. The central nucleus is pushed the opposite way to which the spine bends during movement, like the way a waterbed displaces to the other side when a person lays on it.
Altogether discs make up approximately one quarter of the height of your spinal column. They are in their best condition at birth. Discs are slightly larger in the morning after sleeping because they have absorbed fluid whilst you have been laying down. As the day progresses gravity compresses the disc causing it to become slightly thinner. This is why you are taller in the morning!
Disc Degeneration
Over the years everyday wear and tear causes degeneration, or narrowing, of the disc. This is further compounded with injury. This constant workload causes the disc to reduce in thickness and it is estimated that once you have reached sixty years of age you will be about three centimetres shorter than at your maximum height. This degeneration can have a major influence on the size of the opening between the vertebra through which the spinal nerves pass.
Protruding or Bulging Disc
The central nucleus moves backwards during the forward bending of the spine. Everyday stresses combined with injuries and poor spinal maintenance can cause the outer annulus to weaken. The nucleus can then push on this outer ring, breaking some fibres and causing the annulus to bulge out. A bulge can be large enough to compress and irritate the nerve root as it branches off the spinal cord causing ‘nerve root compression’. However it is possible to have a disc bulge present which may not produce symptoms but is indicative of some degenerative changes.
Prolapsed or Ruptured Disc
If damage to the annulus (the outer ring) is severe enough, the nucleus (jelly centre) can actually rupture through the annulus and in the spinal canal potentially pressing upon the spinal nerves or spinal cord. This also may cause nerve root compression. The amount of pressure to adversely affect the function of the nerve has been shown by researchers to be the equivalent to the amount of pressure you can physically apply to your eyeball with your finger. Thus the spinal nerves are very sensitive to pressure which is why you need your chiropractic care to maintain proper disc biomechanics. This can be further enhanced by utilising proper lifting techniques and postures that minimise any rotation.
If you are experiencing protruding or bulging discs and want to discuss treatment with your chiropractor, book online @ https://www.centenarychiro.com.au/ or call us today on 07 3381 0440
