(Chapter 31) Footnote 1:

Or “calf,” the term used by Celsus (e.g. 7.1.26), who uses fibula only of a pin or clasp used to close a wound (e.g. 5.26.23B). This usage is followed by Berengario ( Isagogae breves, 1522). The modern use of fibula is based on the Hippocratic use of pero/nh (brooch, like Lat. fibula) for the radius of the arm and the bone in the calf of the leg.