Written by: Kelsey Perreault, DC from ChiroCenter Bloomington
If you visit your chiropractor, you will most likely hear about this thing called the “intervertebral disc”. When I think of these discs, I think of the shrill voice of my Spinal Anatomy professor from chiropractic college – “Good Morning, Doctors!” he used to say loudly into his microphone at 7:30 AM. Ugh. Anyways…I thought I should write a blog post about these little buggers because they are so important in understanding spinal health and chiropractic care in general.
In your spine, you have 24 intervertebral discs found between adjacent vertebrae. In fact, the discs make up approximately 1/3 of the height of the spinal column. (1) These discs do a few things for our spines – they absorb shock (including gravity which is always pressing down upon us), allow free movement in the spine, and give height to the joint to protect nerves exiting the spinal column. You can think of disc anatomy much like a jelly donut – there is an outer ring of tough fibrous cartilage called the annulus fibrosis and a soft, gel-like center portion called the nucleus pulposus.
The reason we chiropractors care about the discs so much is because they are involved in subluxation. Vertebrae can slip out of alignment on top of these discs causing disc bulging and subsequent nerve irritation. In the low back and neck, vertebrae tend to slip back and tip backwards on top of the disc while in the midback, vertebrae tend to slip back and tip forwards. If the disc bulges too much, disc herniations can occur. With this, the annulus fibrosis (outer donut layer) can tear causing the nucleus pulposus (jelly center) to ooze out. Disc herniations oftentimes cause debilitating back pain as the disc contents come in contact with nerves or the spinal cord. They are basically a really intense version of a subluxation.
When subluxation is present in the spine, normal weight distribution will not occur on the discs (think about if your car tires are out of alignment – they will wear unevenly) According to P. Prithvi Raj in his article, “Intervertebral disc: anatomy-physiology-pathophysiology-treatment”, “abnormal mechanical loads are thought to provide a pathway to disc degeneration.”1 Put more simply, when you have spinal misalignment your discs will not wear evenly and will degenerate more quickly. This is one reason why it is so important to have your spine routinely checked, even when you don’t have symptoms. If you get checked for subluxation, you can correct issues before this degeneration occurs.
1. Raj PP. Intervertebral disc: anatomy-physiology-pathophysiology-treatment. Pain Pract. 2008 Jan-Feb;8(1):18-44