On the grace of the limbs

The limbs should be adapted to the body with grace and with reference to the effect that you wish the figure to produce. If you wish to produce a figure that shall look light and graceful in itself you must make the limbs elegant and extended, and without too much display of the muscles; and the few that are needed you must indicate softly, that is, not very prominently and without strong shadows; the limbs and particularly the arms easy, so that they should not be in a straight line with the adjoining parts. If the hips, which are the pole of a man, are placed so that the right is higher than the left, then let the right shoulder be lower than the left and make the joint of the higher shoulder in a perpendicular line above the highest prominence of the hip. Let the pit of the throat always be over the centre of the ankle of that foot on which the man is leaning. The leg which is free should have the knee lower than the other, and near the other leg. The positions of head and arms are infinitely varied and I shall therefore not enlarge on any rules for them. Let them, however, be easy and pleasing, with various turns and twists and the joints gracefully bent, that they may not look like pieces of wood.
That is called simple movement in a man when he simply bends forward, or backwards, or to the side.
That is called a compound movement in a man when some purpose required bending down and to the side at the same time.…
source: encarta encyclopedia