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THE ANATOMY OF THE SPINE

Have low back pain in Greenville SC? Maybe it's time to learn a little about the spine! The spine is very complex and even with a doctorate degree there is always more to learn about the spine. This blog post is aimed to give you a basic understanding of spine anatomy, function, and pathology reasonings so that future blog posts can focus more on what causes spine injuries, treatment of spine injuries, & prevention of spine injuries. For general spine treatment, please check out my free ebook resources by clicking HERE. So let’s dig in:


‚ÄčThe spinal column is designed to protect our spinal cord and acts as our foundation for movement. It is comprised of 33 vertebrae, which are divided into 5 different regions: 7 cervical vertebrae (the neck), 12 thoracic vertebrae (the upper/mid back where the ribs attach), 5 lumbar vertebrae (the lower back), the 5 fused sacral vertebrae (the sacrum, which wedges between both sides of the pelvis), and the 4 fused coccyx vertebrae (the tailbone). Each vertebra bears the entire body weight above it until it reaches the last lumbar vertebra, which sits on the sacrum and disperses the entire upper body weight across the entire pelvic girdle. Every region of the body has a curve of a particular degree either inward or outward. Any variation in these curves – from increase or decrease in curve, to even rotational or side bending curves – are considered pathological. Variations in these curves can be due to muscle imbalances on either side of the spine, boney deformity, compensation techniques to avoid pain, functionally created through postural habit, or genetic predisposition. Changes in these curves can cause changes in pain and changes in muscle function, joint mobility, and general movement.
 
There are numerous muscles that attach to our spine but there are far too many muscles to describe. Instead, just know it is important for these muscles to be strong before any other movement can occur away from our spine. Since we initiate all movement first from our spine, our spine must first be stable. If the spine is not stable, then any movement we perform with the upper or lower extremity will be less efficient and more uncoordinated. The movements of the spine are: flexion (bending forward), extension (bending backwards), side bending to the left and right, and rotation to the left and right. These movements can occur at all regions of the spine, but our greatest flexibility is in the cervical and lumbar regions of our spine. Therefore, these areas are more prone to injuries.
 
Between the large spaces of each vertebra of the spine a nerve root emerges from the spinal cord. These nerve roots are large leaving the spinal cord but split into several separate nerves as they move further from the vertebral column and spinal cord in order to provide innervation to all muscles and organs of our body. This is why you may have pain, numbness, tingling, or burning sensations far from the spine, but the issue may be originating from a spinal column or spinal muscle dysfunction putting pressure on the nerve roots. Furthermore, this is why you may have changes in your muscle strength or bowel/bladder function from a spinal column dysfunction.
 
Between the bodies of each cervical, thoracic and lumbar vertebrae of the spine is an intervertebral disc. Our nerve roots pass behind these intervertebral discs before leaving the spinal column. Also, these discs are usually a certain height to allow the nerve roots to have enough space to pass between the vertebral segments. The purpose of these discs are to stabilize the vertebrae, while also distributing load equally throughout the spine from the constant downwards forces occurring from gravity. The intervertebral discs are made-up of 80% watery gel and are each surrounded by a fibrous outer ring. Therefore, hydration is important for spine health. If you’ve ever noticed, we get shorter with age and at the end of the day. This is because water is squeezed out of the discs from gravity’s constant pressure pushing down on us. When you are laying down (sleeping), your discs are under less pressure which allows for them to re-hydrate. While the discs naturally shrink every day, they should be re-hydrated every night. When a disc does not hydrate properly, this shrinks the vertebral spaces at that segment until there is far too little space for that segment’s nerve root to pass through. This then causes pressure on that nerve root, thus causing pain and the various other symptoms mentioned earlier. Secondarily, if we tear the fibrous ring around our disc (typically from a lifting combined with a twisting motion) then this watery gel will press through the fibrous ring and onto these nerve roots as well – aka a herniated disc. Therefore, drink your water! Especially as we get older since we dehydrate quicker.

 

 
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