So when you're talking about a heart pacemaker as a prosthetic, you're talking about something that isn't just, "I'm missing my leg," it's, "if I don't have this, I can die."
심박 조율기같은 물건이 대표적이죠. "다리 한 쪽이 없어요." 하는 그런 물건이 아니라 "이게 없으면, 전 죽어요."