In the human body, the way a healthy spine should move differs quite vastly from other joints. There are two interrelated reasons for this:
1. Anatomy of the spine
2. How the spine is represented in the brain
Anatomy of the Spine
While the knee joint or hip joint is comprised of one single joint, the spine is comprised of 24 individual segments (or vertebrae) each consisting of a pair of joints called “facet joints”. This equals to a total of 48 individuals joints that are responsible for movement in the spine. When a healthy spine moves, a little bit of movement should occur at each individual segment of the spine (as opposed to all of the movement coming from one or two segments). The purpose of having movement distributed across many segments is to more evenly distribute forces. When forces are not evenly distributed and movement only occurs at a single segment (known as a “hinge-point”), risk for tissue overload and subsequent injury increases. Picture a chain – each segment (or link) in the chain should be able to move in order for the entire chain to function properly. If only one link in the chain can move and the others are blocked, this one moveable link will wear down and eventually break. Alternatively, the links in the chain that are blocked from moving may also eventually break down because they are being forced to bend where little or no movement can occur. Both cases increase the risk for injury.
The Motor Cortex
Each part of the human body capable of movement is represented within the brain in an area called the “motor cortex”. Body parts such as the hands and fingers that are represented by a large area in the motor cortex allow them to move very freely and with much control. This is the reason it is much easier to pick up a pin with your fingers rather than with your toes, as the latter has smaller representation in the motor cortex. Similarly, the spine takes up a relatively small amount of real estate within the motor cortex. While each individual finger of your hand is represented by a large area in the brain, the spine is represented as a single unit by a relatively small area in the brain. This means that the individual segments of the spine aren’t “meant” for large movements with many degrees of freedom like your fingers are. Instead, large movements of the spine should be produced by the summation of smaller movements occurring at individual spine segments.
Is your spine healthy?
So, it matters where the movement is coming from when you bend your spine. Is movement coming from multiple areas? Or is it coming from one area? If movement is only able to be generated by one or two segments, risk for injury is much higher. This is simply because the forces getting put through the spine will be funnelled to one area instead of being evenly distributed across the entire spine. This is especially important in athletes that require repetitive spinal bending, for example tennis players and gymnasts. If your spine isn’t capable of moving segmentally, have no fear – it can be treated manually and trained to do so. Come visit us at Ace Sports Clinic for an assessment and begin your journey to spinal health today!
