The arm is made up of 4 joints. The first one is at the sternoclavicular joint where the sternum meets the collarbone. The second is at the glenohumeral joint where the upper arm bone meets the shoulder blade. The third joint is at the elbow and the fourth and final joint is at the wrist. There are more joints and articulations involved but these are the major players. How do you have your arm mapped?
Many people I’ve worked with think and act as though the first joint of the arm is at the glenohumeral joint. This orientation can work just fine for a lot of activities, but it leaves a lot of range of motion, versatility and nuance on the table. If your current map is leaving you feeling limited or uncomfortable, shifting how you perceive your arm may give you more options for movement. The image below is of the whole arm. See the collarbone connect at the sternum and the acromioclavicular joint of the shoulder blade?
Using your fingers, find the where the collarbone meets the sternum (the SC joint). Take your time and feel around. Now, using your index finger, find the tip of your nose and then find the SC joint again. Was it easier to find your nose or SC joint? Go back and forth finding the tip of your nose and your SC joint. Most people can easily find the tip of their nose. When you can find your SC joint just as easily, this is a sign that you are on your way to having your arm mapped in this new way.
We’re going to spend the next week or so taking a closer look at the arm. We’ll look at joint sizes and locations, play with how the forearm rotates and discuss one of my favorite phrases, humeroscapular rhythm. We’ll map the hand and fingers while we’re at it. See you tomorrow.