(click for larger version)
Medea's pose is inspired by the "pinwheel stance" of the Gorgon on the West Pediment of the Temple of Artemis at Corfu, for several reasons. The stance is supposed to convey motion, hopefully emphasizing the violence of Medea's actions. The pinwheel stance could possibly be interpreted as a "hex sign," tying in with Medea's powers of sorcery. And lastly, Medea, like a Gorgon, is a strong & dangerous female character in Greek mythology.
Thanks go to H.W. Janson's History of Art for the inspiration. :D