That part of the fore limb between the brachium and the carpus; the forearm.

Then would come a happy cure to aching bones—made whole with honourable bruises, oblivious of pain, the "brachia livida," lithesome and triumphant.

The passage from Erasmus, "brachium habet ova serpentum," is plainly to be rendered "and with a string of serpents' eggs on your arm."