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  • Writer's pictureMia

What the hell do shoulders do? Part one.

Updated: Aug 11, 2020

Should we talk about shoulders?

By far the most vocal and happy response to this blog read 'ROUND THE WORLD was to my sprained ankle series. (Thank you, to my five readers. You are doing God's work.)

So I thought I'd take it north and move into an in-depth look at one of your most gorgeous joints: the shoulder. Let me start right here: If you remember nothing else from this blog because you're just about to hit the X button, remember this. The shoulder blade is the prom queen. You keep her happy or she's gonna light you on fire and post it to her insta. Not even her feed, just her stories. You know why they call her "H"? Because she turns asses to ashes.

Do shoulder blade work. Do shoulder blade work. Do shoulder blade work.

I'm starting with basic anatomy, because you can't understand shoulder mechanics without it. After that we will flirt with physiology. Once you know what's moving and how it moves, let's take a dip into how dreaded injuries like rotator cuff, impingement, and AC joint issues crop up. After forcing you to read dozens of pages about the coracohumeral ligament and the osteokinematics of the sternoclavicular joint (no I'm just kidding don't leave it's only gonna be the acromioclavicular joint), I'll hit you with my favorite ways of strengthening, mobilizing, and encouraging the shoulder to perform whatever high-level activities you need it to perform. And finally finish with a piece about how shoulders age and what we can do to keep them healthy and mobile all the way 'til the end. You'll be the corpse with the strongest rotator cuff in all the land.

Soooooo, what's in a shoulder?

The shoulder joint is made up of three bones that are barely attached to each other. This allows the shoulder to move as freely as it does. Straighten your elbow. Feel how it has a specific end point and if you go further it will certainly break? That's because your elbow bones lock into each other for increased stability. The shoulder is free to swing in an enormous radius because none of the bones locks into another bone at that joint. Instead, they're like a group of shitty ten year old kids. They all just hang out near each other, each encouraging the others to do whatever the fuck they want. Anything goes so long as no one gets hurt. The shoulder is a lawless town.

What are the three barely-hanging-on bones that let you swing monkey bars, do handstands, and flip off the car that cut you off? The humerus (the long upper arm bone), the scapula (the shoulder blade), and the clavicle (the collarbone). The humerus sits against the essentially flat surface of the shoulder blade, and the clavicle serves like a tent pole to keep the entire shoulder from collapsing in on itself. The scapula is the primary mover. No matter what direction you're intending to reach, it's your shoulder blade which decides if you're going to get there. The shoulder is called a ball-and-socket joint, but it's really more like a golf-ball-pressing-against-a-quarter joint.

Here is my nifty sifty anatomy app showing you the basic makeup of the shoulder joint.

How does a vertical arm bone stay connected to a flat surface? Anatomical brilliance. First, a host of ligaments spiral around the joint capsule. On top of that are your pec minor (the smaller chest muscles underneath your big chest muscles) and the famous rotator cuff, which sounds like a snazzy bracelet that encircles the joint but it's actually four different muscles. Three of them are in the back of the shoulder, and one is in the front. They pull tightly from multiple directions to help the humerus translate properly across the socket and also not fall out of it.

Stacked like pancakes on top of the small muscles are all the big-ass arm muscles that you've heard of: Pecs (chest), delts (shoulders), and lats (back). Moving down the chain towards the hand gives you biceps and triceps, both important shoulder assistants, and moving up the chain towards the spine gives you all the rest of the seventeen muscles that attach to the shoulder blade. Did I mention the shoulder blade is important?

It can't just be muscles, right?


There are a couple other ways that the body has developed to keep the shoulders in place. First, I often joke about how the traps (your upper back and neck muscles that are always craving a massage) have zero chill. You know that guy at a party who does an impression that makes everyone laugh, but it over-encourages him and he does it fifteen more times that night and in the end you just wish he would stop talking to you? That's your traps.

Even Aly's traps have zero chill

However, there's a reason for trap overexcitement. The tension from the traps and levators between the neck and the shoulder joint helps to tilt the shoulder blade slightly upwards. This gives the humerus a little bit of a shelf to rest on. In very deconditioned people who are hunched over a computer all day, the traps don't have the strength to maintain that tension. The traps sag instead, which inevitably makes the shoulder blade sag. This loss of shoulder blade positioning completely changes the way the humerus rests in the socket. A loss of trap strength means your arm bone will fall against the bottom of the socket which, like your weird friend Colin at a strip club, is not meant for grinding.

There is another consequence of this altered shoulder blade position. You may have heard of the supraspinatus, which is your uppermost rotator cuff muscle (highlighted in photo) and which frequently gets pinched and impinged. An impinged supraspinatus tendon makes it terrible to reach behind you or overhead. It's seriously inhibiting. Good luck putting a jacket on by yourself.

What does this have to do with traps? We said that a strong upper back helps maintain the scapular position. One important component of that specific scapular angle is that it preserves juuuuuuuuust enough space for a bunch of tissues to squeak through. In between the top of the humerus head and the bottom of the acromion is only about one centimeter of space. One centimeter! It holds the supraspinatus; the supraspinatus tendon; a bursa which is a little puff of tissue that prevents the muscle from dragging along bone; one of your biceps tendons; AND the upper part of your shoulder capsule ligaments. That one centimeter packs a punch. (Way more than I can say about my ex-boyfriend.)

In that degraded scapular tilt--which happens with soft, squishy traps--the bone moves in on that precious little space and smashes everything in there together. Hello, impingement, my old friend.

The last way that your shoulder joint stays in place is through a real cool design by physics. I told you that there is a ligamentous capsule which surrounds the ball and socket tightly. The capsule is so tight that the interior of the joint actually stays at a slightly negative pressure relative to the outside of the joint. This creates a bit of suction to help the arm stay sucked against your body. YOUR ARM IS ITS OWN SUCTION CUP HOW COOL IS THIS.

OK, so, muscle ropes, finicky tilting, and a suction cup. Sounds like an awful porn setup.

How does this joint even move?

Your three shoulder bones are highly mobile and highly interactive with the rest of the body. Your collarbone, for example, gets wedged into your sternum, providing a lever for you to be able to help your neighbor get their suitcase up into the overhead compartment. Your humerus, like your massive thigh bone, is capable of transmitting huge amounts of weight safely into and out of the tiny bones of the wrist and hands. Think of a gymnast, a major league hitter, or a strongman competitor. And your shoulder blade, although it has a ton of muscle attachments, has virtually no bone attachments at all. This allows it to "swim" through your rippling back muscles, bound by nothing but the limits of your own strength. The stronger your back is, the better your shoulders will function.

Quasimodo has some shit happening in his subacromial bursa for sure

It's this scapular movement that is most crucial to understand. As I said, the bones in your shoulder are barely connected. They are not what is responsible for shoulder stability. Your shoulder ONLY works properly if you have strong scapular muscles. You might have heard internet experts saying all kinds of things about shoulder blades. Pin the shoulder blades, lock the shoulder blade into place, squeeze your shoulder blades, etc. The next part of this blog is going to address this confusion, so come back for it. But today we're still talking about anatomy, so let's finish this off by looking at how all those shoulder blade muscles interact.

The shoulder blade glides amidst an impressive assortment of muscles and is responsible for about a third of your arm-moving-overhead abilities. In other words, if your shoulder blade is weak or restricted, any overhead movement is going to become a problem. Not just lifting, either. Painting, playing with kids, throwing a ball, etc. The more force you're expecting to go through your arms, the more you're gonna need to turn your shoulder blades into a fortress.

To do this, you'll have to understand that the shoulder blades...shoulder...a massive burden in the upper body. In order to make the shoulder joint move successfully, the shoulder blades have two functions. They contain muscles which stabilize the shoulder by originating from somewhere else (like the spine) and inserting onto the shoulder blade. Then there are muscles which mobilize the shoulder which originate on the shoulder blade and insert somewhere else (like the arm).

So the shoulder blades need to be able to be stabilized in some parts and mobilized in other parts. Always. At the same time. No matter what direction your arm intends to go. Holy shit. No wonder no one can figure out if they're supposed to be "pinned," "locked," "squeezed," "shrugged," "packed," or many other verbs. Remember in "A Walk To Remember" (how could you not? the title literally tells you to remember it) when Jamie tells Landon that one of her dreams before she dies is to be in two places at once? This is what your shoulder blades are craving too. They need to be in two places at once. (Shane West, call me.)

As promised, the next part of this blog is going to talk physiology, so we'll get into how to teach your scapula to be in two places at once. But for now, here are a couple ways of attending The Shoulder Blade Center For Shoulders Who Can't Move Good And Want To Do Other Stuff Good Too.

Shoulders and Shoulder Blades: Emulsification

Yes, I'm suggesting you emulsify your three shoulder bones into a beautiful balsamic boneaigrette.

Like a fantastic dressing, the oil and water need to be well-balanced and well-distributed, but will necessarily retain their own characteristics no matter how much you shake them together. The idea with successful upper body training is to emulsify all of your movements. The shoulder blades do their thing, the humerus does its thing, the collarbone does its thing, but they do them in a well-distributed way. You're not trying to separate the oil from the lemon from the balsamic, and you're not trying to separate the shoulder blade from the arm bone from the collarbone. You're trying to blend them evenly throughout the entire suspension.

Shoulder blade movement IS part of shoulder movement. Not shrugged, not pinned, not anything. Don't give your shoulder blade a verb. Just consider how it is an extension of your arm bone and shoulder and therefore ought to move accordingly.

Example movements to try with relatively light resistance (if a movement is super heavy, it's going to be too hard to identify specific scapular patterns):

1) A pushup. On the way down, the shoulder blades move towards each other while the elbows are bending. On the way up, the shoulder blades move away from each other as the elbows are straightening.

2) A bicep curl and shoulder press. During the curl, try to feel your shoulder blade tilting a bit (the point at the bottom will move closer to your rib cage). Then during the press, it will tilt and rotate. If your right arm is pressing, your right shoulder blade will rotate in a counter-clockwise direction. On the way back down, pay attention to how your shoulder blade begins to rotate back towards its starting position. As you let the curl back down, ignore your bicep and focus instead on the un-tilting of the shoulder blade as your hand returns by your side.

3) A lat pulldown or a pullup (only if pullups are easy for you). As you begin to pull downwards, laser focus on your shoulder blades. Did they shrug immediately? If so, start the rep over. They'll want to depress and keep depressing as your arms continue the pull. When you reverse the movement, the shoulder blades will naturally release along with the elbows.

4) Any kind of horizontal row. It's super common to do a horizontal row without any shoulder blade work at all. Again, the shoulder blades should be emulsified with your arm. When you row, remember that the shoulder blades will pull downwards and backwards, just like your elbows are going to be doing. On the return, the shoulder blades will move away from each other as the elbows straighten.


Don't try to separate your shoulder blade movement

from your arm bone movement.


I'll post a video in the next piece with my own examples of how to work through these ideas, but for now you'll be better off if you don't go into it trying to imitate me. Just practice some simple movement and see if you can figure out what the hell your shoulder blade is doing (you might need to recruit a human who can stand next to you and poke it).

You can try this mental imagery with any arm motion. Bench pressing, power cleans, snatches, ballet, rock climbing, doesn't matter. When all three bones are moving in harmony, trust me, your movement will feel both stronger and smoother.

Shoulders part two is right around the corner! We're gonna talk physiology. What's the most efficient way to move load through the shoulders; how are shoulders affected by your spine, your neck, your wrists (???); and what the fuck is a serratus anterior? It sounds like my favorite knife to stab people with.

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