Discs – Spine Health
Almost everyone has had some bout of low back pain, or if you are one of the lucky ones who hasn’t experienced LBP; you most certainly will know someone who has. Some LBP is relatively minor and can be quickly remedied, but most of us will know or have heard of someone who has “herniated or ruptured” a disc. We have several clients at the gym presently in various stages of disc injury or disease.
Just what are disc? What is their function? What comprises a disc and how does how disc health impact our overall health and life enjoyment?
As I sat down to write this article, I quickly realized after having 6 textbooks and reference books spread over my desk, several internet sources open as well as various articles strewn about, that this was morphing into a huge undertaking. It was proving to be difficult to bring the highly technical and anatomical information together into something that would be relatively easy to read and understand.
I think it is important that some anatomy be presented so you may begin to appreciate these very important structures, but also not to make it too complicated. It has proved to be too much information for one blog post. So, this first installment is the most technical. It presents the anatomical information very briefly. In a future post, I will discuss disc function as it relates to our exercise programs here in the gym and also how we can safely exercise to prolong our disc health. So, are you ready? Here goes:
Discs – Just What Are They?
The vertebral column (or spinal column) consists of 26 vertebrae separated by intervertebral discs which allow flexibility and absorb the stress of movement.
The intervertebral discs make up one fourth of the spinal column’s length. There are no discs between C1 and C2 (cervical vertebrae), and Coccyx. Discs are not vascular and therefore depend on the end plates to diffuse needed nutrients.
The disc transmits loads through the spine and because of its position between two vertebrae, it provides for the flexibility of the spine. The disc also distributes loads through the entire disc.
Discs consist of three components:
1) the annulus fibrosus: the collagen fibers of the annulus in each layer are organized in a manner similar to tendons and are well suited to resist tension. The collagen framework of the annulus provides the spine its flexibility.
2) nucleus pulposus: water is the primary component of the nucleus, but it also contains a mucoid material composed of different cell types and fibers. The health of the nucleus relies on the changeover of fluids which is assisted by the movement of the spine. The nucleus acts a shock absorber and helps to keep the vertebrae separated.
3) cartilaginous endplates: these anchor the discs in place. The disc is predominantly avascular so depend on diffusion of nutrients through these endplates. These endplates also provide a link between the the blood supply found in cacellous bone of the vertebrae and the central region of the disc. They also contribute to the mechanical function of the spine.
Disc Injury and Disease:
The earliest signs of degeneration of the disc includes the loss of water content from the nucleus or evidence of tears in the annulus fibrosus. Because of these changes, the disc space begins to narrow and stability of that segment of the spine becomes compromised.
1) Protruded disc – the central mass of the disc intrudes into the the ruptured inner fibers of the annulus. The peripheral (or outer) fibers remain intact but a general bulging of the disc occurs.
2) Extruded disc – the nucelar material has penetrated the outer walls of the annulus but the tissue is still connected to the central core of the disc.
3) Sequestered disc – the posterior logitudinal ligament is ruptured and one or more fragments of the herniated material is present in the spinal column.
Making the diagnosis of a herniated disc, and coming up with a treatment plan depends on the symptoms experienced by the patient, the physical examination findings, and the x-ray and MRI results. Only once this information is put together can a reasonable treatment plan be considered.
Treatment for a herniated disc begins conservatively and progresses if symptoms persist:
1) Rest and activity modification. Most disc herniations will resolve if proper rest and precaution with activity.
2) Ice and Heat
3) Physio Therapy – lumbar stabilization exercises are essential to deload the disc and vertebrae.
4) Anti-inflammatory medication may be warranted
If there is severe neurological symptoms, surgery may be necessary. A discectomy may be performed to remove disc fragments.
In our next blog post, we will discuss exericse/fitness and how it relates to disc health. Also, some myths will be uncovered and research leading the way on how we treat back disorders, exercise selection and lifestyle choices will be presented.
Till next time,
Mechanical Low Back Pain, Perspectives in Function Anatomy, Porterfield & DeRosa
Concepts of Human Anatomy & Physiology, Van De Graaff/Fox
Low Back Disorders, Stuart McGill