Upon further exploration of the left hand, I noticed that the arm plays an important role in providing balance to the hand. I like to use the chicken wing metaphor when describing the up and down motion of the arms. This helps distinguish the upper arm from the shoulders and forearm. When it’s elevated, it also gives the hand a stabilizing table to connect to, requiring less effort from the wrist and finger muscles.
But there’s another arm motion, the forearm one. It correlates to vibrato, it was recently explained to me. It’s like a pushing motion, or like when you gesture to someone to back away further. I believe the muscles used for this help support the angling of the hand and fingers. It’s a little like having a prosthetic arm or a mannequin arm, where you can move the arm around while keeping the hand still. The arm is doing most of the work. The hand must be loose, of course.

originally published on 1/3/10