Metacarpus

They sound like a pair of long dangerous scissors or a wonderful exquisite sword - like the green destiny, something that would snip metal with the same ease as we would think of tearing the morning's front page. But, she discovers that ten of them are present in every normal human and chimp and that they are not exactly made of cold forged steel.

She also discovers that it can hurt horribly, when a ligament tears between a carpus and a meta.