@drgnclw Some non-professional anatomy notices (learning by analysis :)). By brachioradialis position I assume that it’s half-pronation, right?
Sorry for my poor drawing skills, but I think muscle position should be more like this then.
And, of course, it’s a very rough scribbles, better to look at anatomy reference 😀

If you want to learn anatomy, I can recommend “Anatomy for sculptors” book by Zarins and Kondrats.