We all have them, the big broad bones that fold onto the back of your ribcage like wings. But what do we really know about them?
To understand the function of the shoulderblade, or “scapula,” we must first understand their form.
1. The only bone to bone attachment of the scapula to your trunk is a tiny joint where your collarbone meets the top tip of the scapula.
This joint, called the acromioclavicular joint, or AC joint, is about as secure as if you put the tips of your two index fingers together head on, i.e. it’s pretty flimsy.
The crazy thing is that the arm bone attaches to the scapula bone via a shallow concavity, and the scapula is attached to the rest of your body via the above mentioned AC joint. Literally the only bony attachment of your arm to your torso is via a tiny, flimsy joint.
So, you’re probably wondering at this point, “how is my arm not falling off?” It is pretty amazing that our arms not only stay attached, but that we are able to climb, crawl, draw, reach, swim, etc with such precision and stability.
2. It is mostly muscle that holds our arm onto the rest of our body.
This is an amazing design because it allows for a huge degree of mobility in the shoulder, which is necessary to do all the precise tasks and vast ranges of motion required of our arms.
However, this can also create a lot of problems. Muscles change their function based on their position, and repetitive, habitual movement patterns can place muscles in suboptimal positions. If we always sit at the same desk, with our phone on the same side, or we always sit the same way in the car, or always throw a ball with one hand, we are slowly but surely ingraining one-sided patterns into our bodies.
When this occurs in the shoulder and shoulderblade regions it is especially impactful due to the heavy reliance of the shoulder on muscles for stability. This is why shoulder injuries often have little to do with the shoulder, unless it was due to a direct trauma. Usually it is a muscle imbalance or aberrant positioning around the scapula that is the issue, even if the pain is felt in the shoulder.
3. Our shoulderblades are concave in shape
Even though at first glance it seems that are shoulderblades are flat, they actually have a concave shape. This allows for the shoulderblade to sit on the ribcage, which is egg-shaped.
However, many of us tend to change the shape of our ribcage by changing the way we breathe. For example, a common pathological breathing pattern is pushing the front lower ribs up in order to get air in without completely exhaling. This is a common breathing pattern when we are stressed- it is a shallow, more rapid breath. If we are a little stressed most of the time, our breathing will reflect that, and over time the shape of our ribcage will reflect that as well.
What this “stress breathing” pattern does is create a flattened ribcage in the back, so now we have a concave shoulderblade trying to sit on a flat surface. At this point the muscle activity cannot be restored because it is the structure underneath that is the issue, and must be corrected before the shoulder can start to move better and feel better.
The shoulderblade is often overlooked when we think about how we move our bodies, but its position and function is vital to our arms being able to move well and without pain. Keeping the muscles around your shoulderblade strong and in an optimal position, as well as keeping your ribcage well positioned with proper breathing, will preserve the life of your shoulders and make for a much happier and painfree shoulder complex.
