This is the most important part of guitar mastery because guitar playing is a physical process. Musicality is not as important because one will find that when one masters the instrument, a floodtide of creativity will be unleashed. So we need to focus on the mechanics of the hand and arm and how the nerves, muscles and bones all work together to express the ultimate source of feelings from the heart.
The fingerbone's connected to the handbone, the handbone's connected to the wristbone, the wristbone's connected to the armbone, the armbone's connected to the elbow, the elbow to the upper-armbone, to the shoulderbone, to the collarbone, neck and backbone, and finally to the ribbones where the heart and lung muscles passionately pump when one plays. The rib, back and neckbones send muscular flexations intertwined with nervous electrical impulses through the collar and shoulderbones, down the upper arm, through the elbowjoint and down the forearm, through the wrist, out the hand and down to the fingertips.
Each point is crucial as an integral function of a complicated machine. When we understand how it all works, then we can perform more efficiently. Let's start with an overview of the hand: