In listing the parts of the human arm in its entirety, we need to include a collarbone and a shoulder blade, in addition to the upper arm bone (humerus), forearm, wrist, and hand.
A human arm is not what we see on a Barbie doll- it is not a limb that sprouts off the side of the body. The collarbone and shoulder blade are the parts of the arm that are most frequently left off the list when we ask our students to name all the parts of the arm. It is the collarbone and shoulder blade unit, or the “upper arm structure,” that allows us all the large arm movements that Barbie cannot do. Barbie could not go swimming; in particular, she couldn’t do the front crawl stroke, because her makers did not equip her with a moveable collarbone and shoulder blade. Nor could Barbie play the violin, the cello or the flute for the same reason.
Students who have been taught to “keep the shoulders down” frequently have the misconception that the arm shoots off from the side of the body like Barbie’s. They will likely believe that the shoulder joint consists of a ball that fits inside of a huge socket which is completely separate from the shoulder blade. If you ask them to show you, they will likely gesture with a fist fitting into the “claw” shape of the other hand. They will believe the fantasy that there is a socket over at the side of the body, that the shoulder blade belongs on the back, and that there is absolutely no connection at all between the two!
Moving this way, especially practicing an instrument in this way, will lead to a lot of unnecessary muscular tension through the upper torso muscles and frequently cause pain in the shoulder joint itself.