Spinal discs are an integral part of the spine, acting as shock absorbers for the impacts of daily life. They take approximately 80% of the force exerted on your spine by compressing under stress and spreading the force into the surrounding vertebra. They are primarily made of 2 main parts; the nucleus pulposis and the annulus fibrosis. The nucleus pulposis is a water-based structure which acts as a compressive cushion for your spine, similar to a waterbed. Since water cannot be compressed very much when in a container, it pushes back against the force being applied which decreases the weight being held by the rest of the spine. The annulus fibrosis on the other hand acts as the container for the water cushion of the nucleus. It is made up of crossing fibres of thick collagen which can twist and conform to forces from all angles very effectively. This stops the fluid centre from slipping around like a water balloon when you squish it. These two parts make up the disc and help to keep the pressure off the less sturdy spinal joints, which are made to allow motion and as such sacrifice their strength.
Increasing forces on these discs, either by adding more weight, bending forwards or by shifting the body’s centre of mass can cause pressure to be put onto areas which are less suited to handling these forces. Bending and twisting forces strain the annular fibres surrounding the disc and can cause repeated weakening of these fibres. As such, with enough weakening, small gaps and tears can allow the nucleus to move within the disc and can cause the weight to distribute a lot less evenly in the joints. This can cause the bone-based joints at the back of the vertebra and the vertebra above and below the disc to take more pressure and start to wear down and degenerate.
Degeneration usually occurs in two scenarios; an abnormal joint under normal loads, or a normal joint under abnormal load. Spinal degeneration in a normal spine is most prevalent with the second option. Daily stresses, lifting incorrectly and staying in incorrect postures can all cause abnormal load in the spine and as such, increase the degenerative process. Degeneration of the discs can decrease their capability of holding normal weights and can also cause the fluid-based nucleus to push on different parts of the disc more. This pressure can compress nerves which exit the spine between each joint and can cause numbness, tingling, pain and a decrease in control of the areas that nerve controls. And it doesn’t take much, even the pressure of a 10c piece on a nerve can cause symptoms to arise. Sciatica is a common issue which can arise from pressure on spinal nerves in the lower back and can range from moderate to severe in pain and disability.
Degeneration is extremely difficult to decrease once it has happened because the disc and cartilage of joints have very little regeneration potential, so once it is gone, it is hard to improve. It then makes sense that reducing stresses on the spine reduces the potential for degeneration, which is where chiropractic care can help. Chiropractors examine the spine to check for any areas which may be under abnormal stresses and use a variety of techniques to help bring the body back to its most stable and natural state of weight bearing, thus reducing the potential for degeneration to occur. If you have any low back pain which travels down the legs, it may be a disc compressing a nerve in the low back. At Anderson Family Chiropractic Mackay, our chiropractors assess your spine to aid in decreasing these abnormal stresses may help decrease the risk of degeneration for the future.
Newell, N., Little, J., Christou, A., Adams, M., Adam, C. and Masouros, S. (2017). Biomechanics of the human intervertebral disc: A review of testing techniques and results. Journal of the Mechanical Behavior of Biomedical Materials, [online] 69, pp.420-434. Available at: https://www.sciencedirect.com/science/article/pii/S1751616117300449 [Accessed 8 Feb. 2020].