Shoulders & Arms | yogawithjames

The shoulder joint is a complicated area of the body, and especially with dynamic styles of yoga, it is used quite often. It has complex movement relative to other joints in our body, and so it is important for us to understand our shoulders, so that we can keep our bodies safe while progressing in our practice.

On the first image to the right is a drawing of the shoulder girdle. Two of the boney structures that comprise our shoulder are the scapula (shoulder blade), which moves around the upper corners of our rib cage, and the humerus bone (arm bone), which moves within the shoulder socket. The reason our shoulder joints have such complex movement is because everytime the scapula moves, the shoulder joint and arm bone moves as well. But additionally, the humerus also has the freedom to move on its own to a certain extent without scapula movement.

The shoulder joint is extremely unique in that there isn't any ligaments that

provide substantial stability. Ligaments being important with most joints as

they bring one bone and connect it to another. The glenohumeral joint is a

ball and socket joint which provides great range and mobility, but comparative

to

other joints, lacks an abundance of stability. The top two figures to the right

you have a drawing of a shoulder blade, highlighting the glenoid fossa, which

acts as a resting point for the head of the humerus to connect to. Moving

below we have a drawing of a shoulder and knee joint. The shoulder joint

highlighting how shallow the glenoid fossa is, and the knee is added to give

a bit of reference of stability between the two joints. Most people who are

fairly active in their lives know through either personal experience, or

somebody they know, that the knee joint itself is fairly prone to injury. But it

is depicted here to show that relative to our shoulder it is supported and

stabilized much more.

So if we don't have stability being provided by ligaments like most joints, where does the stability in our shoulder come from?

The rotator cuff and our scapula. The rotator cuff perform just as ligaments do when it's functioning correctly, by making sure that the humerus stays in the socket of the glenoid fossa during movement. And a simplified depiction of how this is set up is shown on the right. The arm bone being highlighted in red, is held together with our 4 rotator cuff muscles (3 being shown, the 4th is on the anterior side), which at the opposite end, attach to different areas of our shoulder blade and hold it steady. This is comparable to how a circus tent is held, where a center piece is held firm by different attachment points pulling in different directions simultaneously. The scapula provides structural support in that it stacks underneath the arm as its raised. I should note that we always don't want to rely on the stacking of bones in our yoga practice, but as I mentioned before, because our shoulder joint is so shallow, in this instance we definitely do.

One last point to explain before putting this all together, and showing why understanding all this at least to basic extent is so important.

As mentioned earlier our shoulder movement is complex, and so we're going to visit this now in more detail. The way our arms are able to move in many different ways is described as scapulohumeral rhythm. This is combined/coordinated movement of both our shoulder blade (scapula) and arm bone (humerus) which work in sync to create the ability for our arms to move with great mobility. Its pretty hard to mess with most of the ways our shoulders move, but one in particular can be messed with, and it can be very problematic in our yoga practice. This specific motion of our arms is shoulder flexion, which is where our arms reach overhead. Think downward facing dog, or upward salute, and how the arms are positioned on those postures.

Our arm bone starting from an anatomically neutral position, are only able to reach upward about 30 degrees, before it is not able to move any further on its own. What enables our arms to move further is that our scapula can laterally rotate, which is depicted on the figure above, on the right. That figure displays shoulder blades which begin in a neutral position, and then they laterally rotate with the shoulder socket now directed upward.

So now comes the reason why we have been discussing all of this information. What has been viewed sometimes by myself, and a lot more by one my teachers, is that there is a lot of instruction in yoga classes that can create problems in our shoulders.

Located on our figure to the left, we have 3 pictures of the arm bone and shoulder blade. These pictures all have the arm bone in a relatively similar position, but note the difference of the position of the shoulder blade. The arm located at the far left is what happens when the scapulae are allowed to move/rotate naturally. And you can see that the shoulder blade is centered nicely underneath the arm bone. This may not be so important for a position where our legs are providing our foundation, but when our arms are supporting weight in the body, it is crucial that we allow the shoulder blade to move in this way.

The other two images show what happens to the arm bone when someone reaches their arms upward, but then pulls their shoulder blades down. Note the red arrow on the figure to the left, when we create this pulling down action, there is nothing underneath the arm supporting it as the force above the arm presses the arm downward.

But it is not just that bone support from the shoulder blade that we have lost, our rotator cuff muscles are negatively affected by this as well. Because we are pulling this joint into an abnormal position, the 4 rotator cuff muscles acting as our tent for keeping the arm in the socket are now being rendered less effective and more prone to injury. It's important to note that creating that action of pulling the shoulders down does feel stable. But the reason for this is because you're engaging the big trapezius muscle to draw the shoulders down. And although it may feel very stable, it is a false sense of security.

So, please keep this bit of information in your mind if you ever hear a cue from a teacher saying:

Pull your shoulders away from your ears.
Plug your arms into the socket.
Square the shoulders.
Drop into the shoulders.

If you do keep this bit of info in your head, your shoulders will look like the left, and if you don't your shoulders may look like the image to the right with no support under the arm bone, and doing so may lead to injury.

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