The Anatomy of Directing: the Arms & Shoulder

Only two posts left in this series! If you enjoyed what you’ve read so far, please let us know what other topics would interest you. Part of the Da Vinci Project, the Anatomy of Directing series attempts to clarify anatomical points for the purposes of functional mechanics and directing.  If you’re new to directing, check out this post, or the book, Neurodynamics: The Art of Mindfulness in Action. Click on any image to see it in full size.

Part 7. The Arm and Shoulder

Figure 9-4B PPThe shoulder girdle acts as a kind of cross-piece for supporting the arms, which are levers for moving the hand. Because the chest is rather wide, we might assume that the rib cage is wide at the shoulders as well, and that the shoulders somehow hang from the rib cage. Surprisingly, the upper rib cage is very narrow, and it is the shoulder girdle itself, and all the muscles attaching to the shoulder girdle and upper arm, that give breadth to the upper torso.

shoulderThe shoulder girdle is made up of two bones, the clavicle and the scapula. The clavicle helps to stabilize and limit the movement of the scapula, with which it articulates. It is the scapula itself that supports the arm. The outer part of the scapula, called the glenoid cavity, forms a very shallow socket for the ball of the humerus. This joint is somewhat like the ball-and-socket joint of the hip but much shallower.

What is really interesting about the scapula is that the majority of the structure sits in back of the body. Because the sockets are positioned toward the outside, the arms hang at the sides where the socket is. The scapula itself, however, floats freely behind the ribs, embedded in the muscles of the back. What this means is that our idea of a shoulder as a separate body part on the sides of our body is inaccurate. There is really no “shoulder” at all because more than anything, the shoulder is embedded in the muscles of the back, behind the ribs, from which it gets all its support.

Figure 5-3 PPFigure 5-4 PP

That gives us a general idea of the set-up of the shoulder, and a sense of where it is actually located. The joint is formed by the shallow socket at the outer or lateral part of the scapula; the scapula itself is located in the back.

Although the scapula is in back, however, muscles on the front of the body and chest attach to the scapula and humerus, and these muscles cause a great deal of trouble with the shoulders and arms. The shoulders support the arms, which allow us to grasp and manipulate things with our hands. To this end, we have lots of muscles on the arm, forearm, and hand that flex strongly, moving them in very complex ways.

Figure 5-7 PP

Pectoralis minor originates in front of the ribs and inserts into the coracoid process of the scapula.

In addition to the muscles that move the arm, we also have flexors that move and support the scapula itself–in particular, the pectoral muscles that attach to the scapula and the upper arm. What happens is that, too often, we overuse the flexors and pull down in front, and those flexors also pull our scapula forward and down. When that happens, the scapula can no longer function as part of the back.  The shoulders, which are meant to get their support in back, instead become narrowed and held in front.

Figure 5-9 PP

Pectoralis major attaches to the upper humerus. Arrows depict desired lengthening that would allow the shoulder to rest in back.

For the shoulders to work properly, we have to stop narrowing across the shoulders, which allows the shoulder girdle to widen, or what is sometimes called “widening the upper parts of the arms”. When this happens, the shoulders regain their support from the back and, as it were, go back “into” the back where they belong. We then have the sense that the shoulders have regained their natural support and ease and, because the arms are getting the support they need from the extensors in back, we can also use the flexors of the arms with much more efficiency and ease.

The widening of the shoulders is also accompanied by a widening of the back, which seems to spread out and become fuller. As we direct, it’s important to remember that the shoulders are part of the back, not the front, and that we widen both in back and front.

 

Exercise: Linking up segments and directing the arms

Step 1. Sit in a chair with your feet flat on the floor, your back supported, and your hands on your lap with your palms facing down. Give your main directions.

Step 2. Notice your hands. Think of allowing the fingers of both hands to lengthen from your wrists, not forgetting to include your thumbs. It’s sometimes helpful to draw a clear line in your mind, going back and forth several times from fingertip to wrist, in order to become aware of the length between these two points. If you find this idea helpful, try it with all the segments.

Step 3. Notice your forearms. Ask for length in your forearm muscles from your wrists to your funny bones on the inside or lower part of each elbow.

Step 4. Now, link up these two segments, hands and forearms, in both arms so that you’re aware of the length of your arms from fingertips to elbows. Think of your fingers lengthening away from your elbows and your elbows lengthening away from your fingers.

Step 5. Notice your upper arm. Allow the biceps region of your upper arms to release from your elbow to your shoulder joint.

Step 6. Now connect all three segments, linking up hands and forearms with upper arms until you can feel the length of both of your arms from fingertips to elbow to shoulder as a continuous whole.

Step 7. Turn your attention now to your shoulders and ask for length from your left shoulder joint to your right shoulder joint so that your right upper arm is going away from your left upper arm, and your left upper arm from your right upper arm.

Step 8. Now think of linking up your left arm from fingertips to shoulder, across the shoulders, down your right arm to your right fingertips. You should now feel your shoulder girdle widening and your arms lengthening as a continuous whole from fingertips to fingertips.

Step 9. Returning to your primary directions, think of your head going forward and up out of your trunk and your knees going forward and away in the chair. Add the direction for your shoulders to widen across your chest. You should now have a much clearer conception of how the shoulders and arms can lengthen and widen as part of your overall directions.