One of the first changes to take place is deterioration of the disc’s jelly-like centre (the nucleus pulposis). The resilient fluid filled disc becomes dry, replaced by coarse collagen fibres. The ‘drying’ of the disc causes it to become saggy and less supportive.
As the disc sags the cartilage plates of the two vertebrae get closer to each other. This causes the disc to bulge. If this process is allowed to continue further damage occurs.
Normally, the disc acts as a supportive shock absorber for the spine. However, the degenerative changes that occur as a result of the loss of pressure within the disc, promote instability of the spinal joints. The instability allows a greater amount of uncontrolled movement to occur in the joints of the spine. This leads to more thinning and eventually bulging of the disc occurs.
Your body weight is no longer supported by the centre of the disc but instead the walls of the sac (annulus fibrosis.) The thinner and weaker a disc becomes the greater the chance of a disc protrusion gets. This process is commonly referred to as a “slipped disc”. Increased tension on the annulus leads to bony spurs forming on the edges of the vertebrae in an attempt to stabilise the spine.
If the disc is allowed to bulge far enough it will protrude into the space in which the spinal cord and nerves sit. Pressure on the neural tissue, by the disc, results in symptoms ranging from a mild ache to severe sciatic pain. The severity of the symptom is not always a good indication of the state of the disc. Clinically, a very small disc protrusion can cause as much, or more, discomfort as a large protrusion. The mild backache that you experience from time to time may be as a result of a thinning disc or a tearing annulus fibrosis.
It is crucial for people experiencing acute back pain to seek help. It is also very important for those people who have been involved in car accidents or are subjected to other forms of repeated trauma (golf swing, cricket, tennis, etc.) and even those who spend a lot of time sitting at a desk to seek assessment by someone who is professionally trained to assess the function of your spine.
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- Nwuga, V.C.B. (1982) Relative therapeutic efficacy of vertebral manipulation and conventional treatment in back pain management. Am. J. Phys. Med. 6: 273-278.
- Bozzao, A., Gallucci, M. et al. (1992) Lumbar disc herniation: MR Imaging assessment of natural history in patients treated without surgery. Neuroradiology. 185: 135-141.