Thursday, January 14, 2016

Marimba Body: Shoulders

 Though it has been a little while since the last Marimba Body essay, the topic of shoulders has been a theme on the blog with shares of the Rhythm! Scene article, PASIC talk, and the 2015 round-up post.

But, just for continuity's sake, and for the readers who didn't get to attend PASIC (which is a tragedy I'm so sorry), here is some info about shoulders, which happen to be one of the most complex joints of the body.  Here's what I have and am still learning about them.

Shoulders Have Many Parts

For some, imagining the shoulder consists of seeing the 90 degree angle turn at the top of the arm.  This isn't wrong, only incomplete.  As with the hip, what we perceive on the outside of the body is not the actual joint, but the effect of musculoskeletal structure.

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It is not so important to know the names of the bones and muscles of the joint but rather to imagine how the skeletal drawing above exists in your own body.

Here are the basics, as I understand them.
The shoulder is a ball and socket joint that involves three large bones: the humerus (upper arm bone), scapula (shoulder blade), and clavicle (collarbone).  The top of the humerus, known as the humeral head, makes the ball part of the joint, while the scapula forms most of the socket.  The clavicle stretches from the top of the scapule inward to the sternum, which connects the arm to the torso.  There's a great article here, published by a hospital in the UK, that explains the function of each bone further.


3 bones, 2 movement locations

  

Technically, there are 4 small joints that make up the shoulder; however, one need not memorize them in order to avoid injury and learn effective movement.  It is easiest to think of the shoulder as containing two locations of movement: the sternoclavicular joint, and the ball and socket where the humerus meets the scapula.


The sternoclavicular joint allows us to easily reach around a set of 4 timpani, play in a taiko style, perform large reaches on marimba, crash cymbals, play drumset -- basically, the joint is as vital to us as our wrists. Crazy, right?? 

You can watch the instructional video here on how to familiarize yourself with your sternoclavicular joint.

The involvement of the scapula in the formation of the shoulder is very important in terms of realizing how the joint - and the rest of the arm - is supported by the strength of the back.  We tend to think of my scapulae as being part of the back; after all, that is where they are.  The drawing above makes it clear that the bone helps to form the shape of the armpit, and in order to do so, must be more towards the anterior (front) of the body than we imagine.  Truthfully, only one part of the scapula is easily felt and seen on the back - the rest is more central to the body, covered in several layers of muscles. 


Why this Back Connection Matters

Back muscles are big.  (I wrote about them previously in this essay if you'd like to review!)

They are meant to provide great support for our limbs and spine in our upright endeavors.  Particularly, the lats (the large upside-down triangle shapes) support the weight and movement of the arm.  When lats are strong, the shoulder is grounded in strength.  When the lats are uninvolved or weak, the job goes all to the deltoids (find them in the first diagram of this post), which strains the tendons of the joint, resulting in injury and acute pain in various places.
Percussionists in particular can feel pain where the end of the long head of the biceps tendon meets the scapula.  This pain feels very localized and clearly "inside" the shoulder joint.  With this I speak from experience.  As a right-handed percussionist and pianist, my right arm (and all of its supporters) gets a workout due to its higher level of activity; so, when my left needs to play something more active, if I haven't been working on strength exercises I get hints of pain in this place.  Another example: if you've ever painted a room in your house and woken up the next morning with a weird pain in your shoulder, this tendon is probably what's hurting.


Full Circle Support

To sum up the many tid-bits of information here, we can imagine our shoulders as being supported full-circle.  The clavicle connects to the sternum, while the scapula connects to the back, resulting in the shoulder never needing to work on its own.  

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