Ep 499 – The Algorithm of the Supraspinatus: “The Rebel MT” with Allison Denney

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0:01:06.8 Speaker 3: Let me ask you this if we live in a world dominated by algorithms, and if the algorithms are determining the information we consume, and even if the algorithms are not malicious, like there's no human or AI for that matter, deciding which post or which product or which trend should go viral or get highlighted into our feed. But in actuality it is just a matter of collective likes and shares that tip a number over a threshold that feeds a machine that then boosts this post or product or trend to the top of everyone's feeds. Then how do we sort out what is true? I know you can't answer this question right here and right now, but the point I'm getting to is this. The influence that a trend has on our collective subconscious is powerful. You guys know what I'm talking about. Part of the process of gaining confidence in whatever we do is going through long stretches of time in which we are trying this or experimenting with that and deciding if it serves a purpose or simply if we like it. But when in those long stretches of time we don't yet completely know a thing, or totally know ourselves for that matter, we often observe people, especially those people we love and trust, like our friends and family or someone we have decided we respect on the internet and trust that they know.

0:02:27.0 Speaker 3: And so we default to that. So even if this information that we are being fed is wrong, for lack of a better term, history shows that we have a tendency to side with the beliefs that surround us. Mostly because it's incredibly hard to intensely research the right thing when we have 9,000 other things that we are focused on. We don't have time for that. But also because when we see a trend or a product that everyone else around us is doing or using. Our internal need to feel connected tips our brains to accept that this is okay. Before I dive into how this relates to the supraspinatus, let me first acknowledge that this conversation could go in a million different directions. And I want to have all of those conversations. So feel free to drop me an email if you've got some thoughts you want to share. But for now, let's stay focused here and talk about soft tissue.

0:03:29.9 S3: Here is what I think There is a muscle in our shoulder called the supraspinatus. Perhaps you know it. It is one of the four rotator cuff muscles. It lives on the superior aspect of the scapula, superior to the spine of the scapula, hence its creative name, and it is known for its role in abduction of the shoulder. Deep to the upper traps, the supraspinatus originates along the supraspinous fossa of the scapula, that long divot at the top third of the posterior scapula. Side note, the posterior scapula is divided by a horizontally oriented bony protrusion called the spine of the scapula. Above this, or superior to this lives the supraspinatus, and below this or inferior to this, lives the infraspinatus.

0:04:09.0 S3: Makes sense, right? The belly of the supraspinatus attaches along this entire bony fossa, called the supraspinous fossa. As it extends out laterally, it narrows to a point, becomes a tendon, and dives under the acromioclavicular joint, or where the lateral end of the clavicle articulates with the lateral end of the spine of the scapula. Its tendon then adheres to the glenohumeral joint capsule, the ligaments and fibrous container that surrounds the glenohumeral joint and produces synovial fluid. From there it continues out and then inserts itself onto the superior aspect of the greater tubercle of the humerus, or the top of the big bump of your upper arm bone. So here is what all of that means. It means that when the supraspinatus contracts, it does indeed abduct the arm. It tugs on the top of the humerus and lifts the arm away from the body.

0:05:00.1 S3: But the scapula is a floating bone. Not only that, the scapula doesn't necessarily sit neatly in the frontal plane. Not only that, the entire torso isn't entirely locked in a fixed position. Not only that, contractions aren't always concentric. So what does all of that mean? It means so many things. First and foremost, though, it means that there are many, many ways to think about the supraspinatus. What we already know, what has mostly dominated the anatomical algorithm, is that its role as a rotator cuff muscle is indeed important, and its ability to abduct the shoulder is real. But what's not at the top of your feed are incredibly important details that will probably most likely determine new approaches and techniques to address supraspinatus dysfunction. When a muscle, any muscle, contracts, it pulls its attachment sites to the center of that muscle, which begs the whole question of origin and insertion. Noted anatomist and muscle master Dr. Joe Muscolino has made this point vividly clear, and I agree with him.

0:06:09.0 S3: The definition of an insertion moving towards an origin is true if the origin stays fixed. But when either bone at an insertion becomes the more stable of the two, or when you add a mobile component like the scapula into the equation, this definition becomes muddled. When the supraspinatus contracts, it not only brings the arm up into abduction, but it also pulls the scapula into downward rotation if the humerus is stabilized. So let's say you are sitting on the ground with your legs situated to your right, and you are supporting yourself with your left arm. Then let's say that you decide to move yourself into a side plank.

0:06:49.7 S3: With your hand planted on the ground, you raise your hips to the ceiling. In this situation, the humerus is fixed and your torso is moving away from your arm. So in this scenario, the supraspinatus is moving the scapula into downward rotation. And then to add a wrench into everything, the scapula is a floating bone. I mean, they're all floating if you think about it. But the scapula glides around the upper posterolateral thorax and relies on 14 muscles to move it and to therefore stabilize it. So when a person does a side plank, say if some of those 14 muscles are not pulling their weight, the scapula is less engaged into downward rotation and more susceptible to sliding superiorly along the rib cage. If this happens, the space between the supraglenoid tubercle of the scapula or the upper aspect of the glenoid fossa is pressed up into the acromioclavicular joint.

0:07:42.0 S3: And this then, as you can imagine, impinges the tendon of the supraspinatus and often the the nerves, bursa, and joint capsule along with it. To take this one step further, what happens when we engage the supraspinatus into either an isotonic or an eccentric contraction can become equally as convoluted. The plank you just got yourself into denoted concentric contractions or the active shortening of this muscle. But now you need to hold that plank. Your supraspinatus is still engaged, but not creating movement. This is an isometric contraction. Isometric contractions are all about stabilization, but with the shoulder and the supraspinatus specifically, it is especially important because the shoulder is the most movable joint in the body and the scapula is a huge variable in that stability. So, in your side plank, if any one of the 14 muscles at play here are not capable of doing their job, the scapula can become unstable. If the supraspinatus happens to be the culprit, it might allow the scapula to slide superiorly or even posteriorly, which would then create a domino effect of overcompensation, neurovascular compression and, well, probably pain. But then you need to come down out of your plank, preferably with some grace.

0:09:00.6 S3: As you lower yourself down, your supraspinatus should still be contracting so that you don't fall on your hip, but also lengthening. This is an eccentric contraction. With the supraspinatus, an eccentric contraction is going to slow down shoulder adduction, or in this case, impede upward rotation of the scapula. Weakness here in this moment, could result in a lack of control. This may not seem dramatic for a younger person, but the older we get, the more important that kind of control is. And lastly, the scapula doesn't really live in the frontal plane. It may have at one point in your early life, but the natural concave arc of the scapula conforms to the gentle convex arc of the ribcage, which situates the scapula towards the sagittal plane, commonly up to about 30 degrees. Which begs the whole question of abduction as a movement of the supraspinatus. There is, in actuality, a little bit of flexion in there, too. For someone with rounded shoulders, this might mean that strict abduction creates a pinch in the shoulder, and abducting with a slight internal rotation might relieve that irritation. All of that said, here is what I really think. The algorithm of the supraspinatus has been abduction for a long time.

0:10:18.1 S3: This muscle abducts the arm, but with expanded knowledge about how the supraspinatus acts in conjunction with the other rotator cuff muscles, with the deltoids in stabilization of the shoulder joint, in concentric, eccentric and isometric contractions relative to the scapula and and that the scapula is a floating bone and isn't even sitting in the frontal plane to begin with. We then broaden our perspectives and as a result, can better formulate our approaches. The body, just like the collective conscious that dictates our feed, is showing us new material that might be disagreeable, but is also revealing new perspectives. What is trending today did not even exist 20 years ago. What is healthy today was not on the radar 30 years ago. What we know about what a muscle is capable of doing may not have been imagined 50 years ago. The supraspinatus is what it does, how it acts, what it influences and is influenced by, is equally susceptible to its immediate surroundings. Feed the supraspinatus the information that it has a role in flexion, and that is what it will believe. Expose it to insights that it can lower a body down from a plank very slowly, and it will eventually believe that it can.

0:11:35.3 S3: Offer it indications that it works with the team to maintain a functional pattern of movement, and it will become a team player. Algorithms are not necessarily a bad thing. They are another language that most of us, especially the older of us, need to learn. They are simply a different viewpoint that has gained popularity. The plethora of perspectives and experiences humans have at our fingertips leads to an infinite amount of opinions, too many to count. And while this might be overwhelming, we can use our own intelligence to determine what is sound and what is silly. In the same way that algorithms teach us how to speak differently and observe the world rationally, so does our anatomy. Health, soft tissue health, and muscle mobility has a lot of different variables. What a supraspinatus can do in one shoulder might be drastically different from another shoulder, but that doesn't mean we can't work with them.

0:12:33.4 S3: Relating to what one shoulder thinks it can do or can't do because of what it has been told and how it has been trained to act is the beginning to unlocking its strength. So how are we as bodyworkers supposed to move forward with confidence, knowing that what we think we know might shift? We learn from a supraspinatus. Yes. What we thought we knew is still true. It's just expanding. It's not a veering away from the truth into a falsehood. It is just another opportunity to elevate your knowledge and help you help the people who love your work.