Musings on piano technique - The Playing Mechanism

What is the playing mechanism for a pianist? What body parts are used in playing the piano? (Hint: try to think of a body part that is not involved in playing. I think you will be hard pressed to come up with one.)

Role of the entire upper body:

                Core: Support and provide a foundation for the upper half of the body.

                Shoulders and upper arms: Place the forearm, wrist, and hands into optimal position for playing.

                Forearm and wrist: Fine tune the position of the hand.

                Hand: Fine tune the position of the fingers.

All this implies un-impinged freedom of movement of all the components. Tension in ANY of the parts will result in at best less than optimal positioning and movement and at worst can be a career ending injury. Beside these identified parts, we also have sources of tension from the neck, jaw, and even the tongue! (And just to top things off on the topic of relaxation in playing, how many of us even think about our breathing while playing?)