The hands of the violinist are following seam rules of mechanics and physiology as the body of an acrobat performing complex exercises. The anatomical structure of the hand, excluding minor individual differences, is the same for all the people. That is why, in order to hold the bow correctly, a violinist needs at least a basic knowledge of anatomy. He must clearly understand the work of the joints and know what movements each of them can perform.
The shoulder joint - is the most mobile. It can move the arm in all directions. So, to move the bow from string to string, you need to raise or lower your arm at the shoulder joint. The activity of the shoulder joint is also necessary when performing strokes on one string with the lower third of the bow and during slow movements of the entire bow. A soft and silent change of the bow at the tip is best done with the shoulder joint. While the shoulder part of the arm consists of one bone, the forearm has two - the ulna and the radius.
The elbow joint is double: one for the ulna, the other for the radius. The first joint in which the ulna connects to the humerus controls the flexion and extension of the forearm relative to the shoulder. This joint is the most important in the technique of the right hand, since it takes part in the execution of the vast majority of strokes. In the second joint, the radius rotates around the ulna. This joint is extremely important for right-hand technique.
Please, note that a whole range of common rotational moves, such as using a corkscrew, opening or closing a lock, are made not by the wrist joint, but by the elbow joint. In the same way, when holding a bow, the force from the shoulder through the forearm and hand is transferred to the bow. The index finger completes the transfer of this rotational force to the bow.
The wrist joint, like the shoulder joint, can make movement in all directions, but not with the same width as the shoulder joint. Its main function in bowing technique is raising and lowering the hand with frequently repeated changes of strings. The movements of the wrist joint are very limited and are used either for the shortest strokes or as an aid to flexion and extension of the forearm or the entire arm.
The wrist joint aligns the movements of the bow by flexing the arm during the upward move and extending the hand during the downward move. These movements are mostly passive, but they are extremely important.
