The Fish-Tetrapod Transition, evolution of the "elbow" in Stem Tetrapods

The Acanthostega and Tulerpeton limbs seem to form "elbows" in an axis perpendicular to the flexor and extensor plane of the fin. They seem to "flex" their "elbow" forwards, pre-axially. And, I assume, keep it permanently "flexed", a bit as if their humerus, ulna, and radius has been one single "V-shaped" bone. This adaptation positions the primordial hand forwards. Is this pretty much correct? Why I wonder, I always understood elbows as bending in the flexor/extensor plane, but in the first terrestrial life it seems to be in the pre-axial/post-axial plane. That probably has implications for how limbs continued to evolve, and for the embryogenesis of limbs in mammals like humans. I found that interesting.