Welcome to your thoracic spine! Did you know that your thoracic spine, made up of 12 vertebral bodies, is the longest section of your spinal column?
T-spine rests between your neck (cervical spine) and your lumbar (lower back spine) and develops in utero as a primary curve, or kyphotic curve. Yep, you’re supposed to have a bit of a curve outwards in this part of your spine behind the heart area.
The thoracic spine acts as the foundation for the 24 ribs (12 on the left/12 on the right side) that encircle some of your most important parts like the heart and lungs, helping to create the thoracic cage.
Anatomically speaking, the thorax consists of the following:
- The Breastbone(manubrium, sternum, and xiphoid process)
- All 24 ribs
- The thoracic spine (the vertebrae) in the back body, or what we term as the “posterior”
- The costal cartilage in the front body, or what we term as anterior. The costal cartilage attaches the last 5 ribs together
It’s important to understand and explore each region of the spine because each has an independent function working in conjunction with the rest of the spinal segments to create an interdependent relationship. This is what gives our spine the amazing capacity to support variable movement.
I introduced the lumbar spine as part of the functional spinal column family and its role in supporting full body movement in the last “musing”. I offered the basics about primary/secondary curves, what parts make up a vertebra, and how the direction of movement in any spinal segment is driven mainly by the angle/orientation of the facet joints. You can review that blog post at https://mewithlauriebb.com/welcome-to-your-lumbar-spine/.
The main clue, then, in how a particular segment of the spinal column moves (cervical, thoracic, lumbar, sacral) is the orientation of the facet joints on the outside/lateral portions of the actual vertebral bodies.
As you may recall, the lumbar facet joints make it easier for the lower back spine (lumbar) to flex and extend, but not to rotate.
The thoracic spine facet joints are oriented in such a way that the top of the facet joint faces posteriorly, or to the back. The bottom of the facet joint faces anteriorly, or more forward. They basically line up in a vertical plane.
Additionally, the spinous process of the thoracic vertebrae at T5 – T8 (directly behind the sternum) point almost straight down. This provides structure and stability for the mid-thoracic spine.
What does that mean in terms of t-spine movement?
The verticality of the facet joints and spinous processes give the thoracic spine a greater capacity for rotation, a good deal of side bending, mid-back flexion, but less ability to extend (backbend).
Depending on the source one uses, the thoracic spinal segment should make up about 45 – 60 degrees of all spinal rotation.
I want to be very clear that I am not talking about a typical yoga twist where the arms are pulling to create torso rotational movement. I am talking about the actual ability of the thoracic spine to rotate without the help of outside loading.
You’ll need to come to my class in order to see how I approach creating thoracic rotation and mobility. I’ll also be teaching a thoracic spine movement essentials workshop in the winter of 2020.
When you rotate or turn your torso to the right, the facet joints on the right side of your thoracic spine move down and back. The facet joints on the left side move forward and up.
Problems can arise when we lose the ability to rotate the thoracic spine. Most of us living in a body older than a teenager have some asymmetry in our spine, so one side of the thoracic spinal column may feel shorter, tighter, weaker, while the other side feels longer, stronger, more open. This asymmetry can lead to loads being forced downwards creating compensations in the lumbar and sacral regions.
The body always tries to find a way to do what you are asking it to do and other parts will compensate to pick up the slack.
In line with the loads being forced downward comes the fact that the lower portion of your thoracic spine, what we call T11 and T12 are a bit more like the lumbar vertebrae. They allow the greatest amount of extension and flexion in the thoracic spine.
THIS IS A REALLY IMPORTANT THING TO UNDERSTAND!
I continually guide my students and clients away from “popping” or “thrusting” the ribs forward or “hinging” the torso torso back behind the lower back. The above paragraph is the “WHY”, but here it is again—- because the lower thoracic spine is so like the lumbar, it allows for a greater capacity to extend or “backbend”.
We are often asked to “backbend” our upper backs or to “open our hearts” in yoga practice. In order to do this, many develop a strategy of hinging from the lowest thoracic vertebrae. We do this because it’s accessible – these bottom thoracic vertebrae allow that. The rest of the thoracic spine, however, just doesn’t have much backbending capacity.
I said that.
The thoracic spine, especially the mid-thoracic, just doesn’t have much ability to backbend. Period. Try as you might, not much back bending is going to happen above T11/T12.
Look closely at this illustration, especially the top two. In both, the spine is in extension. Notice, however, that the upper and mid thoracic portions are still curved kyphotically – they are not doing what one might think is a backbend. The reality is that the cervical (neck), lower two thoracic vertebrae, lumbar spine, and pelvis are where the backbend is occurring.
Hinging from the bottom thoracic spine can lead to suboptimal movement patterns creating interesting and sometimes problematic load bearing up into the neck and down into the lumbar, and thus, the sacrum/pelvis.
The body always tries to find a way to do what you are asking it to do.
Remember that by nature, the heart of your thoracic spine is slightly flexed (kyphotic). Sure, we need some extension movement in the mid-spine, but not the way it is often cued or taught. Proper glenohumeral flexion (raising the arms up) actually relies on a small percentage of thoracic spinal extension, but not at the expense of losing our thoracolumbar cylinder by hinging at the lowest thoracic vertebrae.
I am willing to go out on a limb and say that many movement instructors have not been taught and don’t understand the functional anatomy and applied biomechanics of what really happens in the thoracic spine or the relationship of thoracic spine to the rest of the spine.
I’m not trying to be dismissive, but only illustrating that a lot of cuing used in the world of yoga is not based in true body mechanics. I’ve found the same issue in the world of weight training and fitness, too.
What typically happens is that when we are cued to backbend the upper back, lift the chest, open the heart, or roll the shoulders down and back, we default to backbending where it is easier for the body to comply, at the lower thoracic spine, and of course, the lumbar spine and pelvis.
Remember, the lumbar spine facet joints allow for extension – back bending. Most of the thoracic facet joints more readily accommodate rotation.
So, we need to be oh so careful in our practice/posture, especially if we are being cued to do things like “lift the chest and roll the shoulders back and down”, because “chest opening” or upper back extension is not actually coming from where we might hope or even be told it is coming from.
There is so much more to say in terms of how the thoracic spine interacts with shoulder function, its intimate relationship with the respiratory diaphragm and breathing, how to create the degrees of extension necessary for full glenohumeral flexion (arms by ears), and how the pectoralis minor plays an important role in the way the upper body moves.
I’ll save that for another day and future musing.
I encourage you to play around with what you truly consider or what you have been told is upper back thoracic backbending. What really happens when you do what you think is upper back backbending? What happens to your lower thoracic when you roll your shoulders blade down and back? Does the upper arm accommodate the actions that the mid-thorax can’t? Where is the motion really occurring? What happens in the scapulae? And, always, what happens in your breathing?
Tell me about what you find yogaburr@gmail.com
I’m happy to investigate, speak about, and teach how this all applies in a functional movement way to yoga asana practice, weight lifting, or any other kind of movement modality. I just need the platform to present it, which is typically in one of my classes or a workshop.
In gratitude,
Laurie BB
