It is by these little things that we determine millions of movements and their meaning. We finally determine and class precisely five million movements of the different agents of the arm. This would seem enormous; but it is nothing at all; it is childlike simplicity. The elements being known, the process is always the same. Hence the advantage of possessing a criterion. With this criterion, we have everything. If we possess nine, we possess twenty millions, which are no more than nine.
Of the Wrist.
The wrist is a directing instrument for the forearm and the hand.
The wrist has its three movements.
It is eccentric when the extensor muscles are in motion.
It is normal in the horizontal position.
It is concentric when the flexor muscles are in action.
In the concentric position the wrist is in pronation, for the thumb is turned downward; this is the sign of a powerful will, because the pronator muscles have more power than the flexors.
In the eccentric position the wrist is in supination; that is, the back of the hand is downward; this is the sign of impotence.
The wrist has also forward and backward movements, either in pronation, in supination, or the normal state. Thus there are nine phases for the wrist.