(Chapter 27) Footnote 6:

Rather fa/lagc, pl. fa/laggej, orig. either a line of battle or a round piece of wood. The word is attested in the anatomical sense first in Aristotle HA 493b29; see Galen De ossibus 2.771.10-18. Though Vesalius does not mention any of the alternative names at this point in the 1555 edition, he gives a Latin equivalent to phalanx, describing the finger bones as instar aciei cuiusdam et agminis (see n. 5 above).