They have full rotary motion in the wrist, and their wrists break backward to show the strain of exertion, just as men's hands do.
The issue I have with this argument made on page 65 is that it all revolves on a comparison to men. Artemesia's women's hands don't have to look like the hands of men in order to have agency, they are simply more accurate and realistically painted, because her hand as an artist has agency and power. Her success has nothing to do with a comparison to men.