3 Things You Should Know About Shoulder Anatomy to Address Shoulder Pain
When I first injured my right shoulder in 2010 I joined the ranks of circus performers, acrobats, dancers, and athletes with shoulder injuries. I was bummed out, but far from alone. It is one of the most common sites for pain and injury for anyone who engages in vigorous upper body activities from aerial arts to lifting groceries out of the trunk.
And it’s no wonder. Shoulders are a complicated piece of equipment and, even though most of us have them, they didn’t come with an instruction manual. When I started to learn more about how shoulders are constructed I was amazed, and immediately changed the way I was training, stretching, and thinking about shoulder movement.
So here are three things that I wish I had known before I injured my shoulder that have helped me in my rehab process and informed the way I address shoulder pain in my clients.
The Shoulder is Not 1 Joint… It’s 4 Joints!
1. The Sternoclavicular joint is the place where your clavicle meets your sternum, right below your throat. We aren’t going to worry to much about this one because there aren’t a ton of muscles that affect it, but it’s important to know that it exists!
2. The Glenohumeral joint is what we traditionally think of as the shoulder joint, where the arm bone meets the shoulder socket. It is pretty mobile, controlled by the rotator cuff, deltoids, pectorals, and lats. However it is vital to know that the glenohumeral joint, if no other joints are moving, cannot lift your arm above about shoulder height and is pretty limited at bringing your arm behind your back.
3. The Scapular joint is the most mobile part of your shoulder. There is nothing but muscle attaching your scapulae to your back. No bones, no connective tissue, just muscles. The scapulae is primarily controlled by the trapezius (upper, lower, and mid), the levator scapula, the serratus, and the rhomboids. These muscles coordinate in an intricate dance to move the scapulae all over your upper back to position the shoulder socket for optimal arm movement. It is this versatility that gives the shoulder its mobility but also makes it extra tricky to control and understand.*
4. The acromioclavicular joint is where the scapula and the clavical come together. Since we don’t have a lot of musclular control of this joint I’m not going to bog us down but it is important to mention that this is another area that can have pain and strains if you aren’t using proper shoulder mechanics.
Only 2 Muscles Attach your Arm to Your Torso, The Rest Attach to the Scapula
So here is this wild, wiggly scapula floating around on your upper back, and the kicker is that the stability of the shoulder is deeply dependent on the stability of this very mobile joint. Only two muscles go directly from the arm bone to the torso. They are big, important muscles though: the pectorals run from the arm bone to the sternum and the latissimus dorsi run from the arm bone all the way down to the base of the spine and the pelvis. These are great muscles for big movements like push-ups and pull-ups, but they aren’t stabilizer muscles.
All of the muscles that provide finer control of the shoulder (the rotator cuff muscles and the deltoids) attach to the scapulae. And that means that no matter how much you strengthen your rotator cuff or pump up those delts, if you don’t have control over your scapulae then you are anchoring those muscles to an unstable surface.
This is why any campaign to improve shoulder health and address shoulder pain must include the muscles of the upper back.
We Must Improve Our Strength, Control, and Mobility in our Upper Back
Almost everyone I work with, myself included, could improve the strength, control, and mobility of our upper back muscles. The scapulae are theoretically capable of amazing ranges of movement and can act as a gorgeous base for shoulder strength and mobility. But poor posture, lack of attention, and just not being aware of what is going on in the back side of our body has a cumulative affect of creating tight, weak, unenthusiastic scapular muscles.
When our scapulae don’t engage and move properly it has a profound effect on the ability of the shoulder to do its thing.
One common example of this is when the scapulae are stuck in an elevated forward rounded position (computer hunch). This means that when we lift our arms over our head to do a pull-up or put dishes away after dinner, our glenohumeral joint, which doesn’t work well one it’s own once the arms are above shoulder height, has to strain past its happy place because it’s not getting the help it needs from the scapular joint. Over time this can lead to the miserable condition known as shoulder impingement and even to tears in the supraspinatus tendon.
That is just one of many sad stories about what can happen with the scapulae aren’t strong and free to do their job.
What I took away from learning all this was that I need to spend much, much more time thinking about my upper back and my scapulae. And that extra time has paid off in reduced shoulder pain, increased stability and mobility, and improved performance overall.
If you are curious about what has worked for me and for my clients, the shoulder series included in the Video Club Membership has a lot of the exercises I love to coordinate between the shoulder joints and build scapular awareness.
*OK, you anatomy experts know I left out the scapuloclavicular joint. This is where the scapula and clavicle come together but since it has very little movement I don’t want to muddy the waters with excess information. But if you have a burning desire to get deep into shoulder anatomy, this is the fourth joint.