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The Importance of Thoracic Spine Mobility
What is the thorax?
Your thorax is composed of your thoracic spine and the rib cage. Your thoracic spine (t-spine) has 12 vertebral bodies, positioned between your neck and low back. It provides the posterior attachment point for your ribs, which act as the base of support for your shoulder blades. Your thorax also protects a lot of important organs internally, but for the purpose of this discussion, let’s keep it simple and biomechanical.
Your rib cage acts as the base of support for your shoulder blades. Your shoulder is inherently unstable as it’s only bony attachment to your body is at your sternum. Therefore, there are a lot of muscles (17 to be exact), that attach to your shoulder blade to keep it stable and attached to your body. As with any appendage in the body, you want to promote proximal stability for distal mobility. Meaning, if you’re going to use your arms to lift heavy things, you need to have a stable shoulder joint to support it.
Your shoulder blade is also a concave surface (think inside of a C). It wants to sit on a convex surface (think outside of the C). Your muscles like it when joints are positioned properly. They can have an appropriate length- tension relationship and everything works harmoniously.
If your base of support (ribs and thoracic spine) aren’t positioned properly, your shoulder blade will move to try to find a better surface of approximation. As with any joint in the body, if poorly positioned, certain muscles will have to work harder as other muscles will work less. Muscles can become long and weak or short and overworked. Tendons and muscles then have a greater chance of getting impinged, strained, or torn. Think of that pec injury when bench pressing, ouch!
On the other hand, if you have a stable base of support and a properly positioned joint, the muscles work really well together. Improved muscle function can lead to improved performance!
Importance for core control.
Your four abdominal muscles all have attachments both on your rib cage and on your pelvis. I like to think of your trunk as a can. You have your diaphragm on top, pelvic floor on the bottom, and abs that wrap around. You have to keep this little can stable to control breathing and intra abdominal pressure. Positionally, if your thoracic spine and ribs are either extended or rotated more to one side vs the other, your ab muscles that attach to it will also be affected. They too have the ability to become long and weak or short and overworked.
Let’s go back to that can analogy. Unopened, that can is very stable. There is a great amount of pressure pushing equally on all parts of the can- it is very strong this way. You can try to crush the can or smash it against your head, but most likely you’ll just end up giving yourself a concussion.
Now, crack open that can. That pressure that was keeping that can stable is gone, the surfaces of the can now have uneven pressure, and you can crush that can with one hand. Not so stable.
A properly positioned thorax allows you to maintain that pressure in your abdomen and stay stable while performing challenging tasks. “Core control” is your ability to stabilize your trunk and pelvis. Again, you want proximal stability for distal mobility. If you have proper control over your trunk and core, performance during any activity is going to improve!
People always think of mobilizing their legs and arms before big events. Don’t you think think that thorax deserves some attention?
What does all this mean?
Everyone understands that core stability is essential to improving performance. In understanding the above information, it makes sense that when thoracic mobility is compromised to perform certain tasks, issues can arise such as creating “pseudo” stability for difficult tasks.
What this can look like inside your body, is over lengthened abs, a compressed lumbar spine, sometimes a flattened thoracic spine, shoulder blades that no longer have a stable base of support, and loss of a lot of mobility.
Biomechanically, if you lock out or extend your back, you lose the ability to rotate. Humans NEED rotation. Every time you walk or go to reach for something, your body wants to freely rotate to make that happen. In a state of extension or locking out, that is hard to do without compromising some sort of ligamentous structure. In some activities, locking out can help you perform activity (I’m not bashing extension), but in the case that you have to vary your activity and go into performing a sprint, you need to have thoracic mobility to improve performance.
An easy way to feel where your T spine is positioned is by feeling your ribs. Put your hands on your lower ribs. Does one side stick out more than the other? Are they both sticking out a lot?
Try to get a sense of how much your ribs and thoracic spine move by taking a deep breath and moving through your rib cage.
An easy way to practice mobilizing your thorax is on all fours. Try rounding and extending your upper back. Use your arms to promote rotation and side-bending. You can make this harder by lifting your knees and practicing some multidirectional crawling as well.
Moral of the story.. If you want to keep your core stable, reduce likelihood of upper extremity injury, and improve performance, mobilize that thorax!