Okay so, I have an ED, (or at least some problem with that), and I have a pretty slim forearm in general, but the half of my forearm closest to my wrist and my hand looks...flat? Like, it is very visible when I tense my arm, but even when I am relaxed, it looks really flat, and you can see my (joints? tendons?) very clearly, and you can feel/see the bone very easily, too.
I wouldn't have been concerned if it looked more normal, but I thought it looked slightly disproportionate...