Physicians say that the thumbs are the master fingers of the hand, and that their Latin etymology is derived from "pollere." The Greeks called them 'Avtixeip', as who should say, another hand. And it seems that the Latins also sometimes take it in this sense for the whole hand:
Endroit: CHAPTER XXVI · ¶3357 Licence: Public domain · Source Le texte est donné tel que dans l'édition, sans retouche.