SPEAKER_05 32:56–33:29
Awesome. Okay. So if I pronate the forearm, okay, what is the difference? So if I'm here versus here, what's the difference in the forearm from a bony perspective? The radius crosses over. Okay. All right. So in parallel, can you appreciate the fact that we're just going to say that the ulna and the radius are now parallel and they're equal. They're not, but let's just say that they are. If I pronate, that means that the radius is now on a diagonal. Can you appreciate the fact that the radius is now shorter relative to the position of the wrist? So because it has to cover, it's on a diagonal now. So if it was here, as it turns on the diagonal, it has to do this, right? It's turning on a helix, basically is what it is. So it's gonna fall back, right? Okay. So then my resting position on my hand is that. Okay. Got it. It means that the ulna now looks longer than the radius. Okay. If I have a radius that twists farther into intranotation, so that means that this is more ER, this is more IR. I've already positioned my hand here. And then that means I can't radially deviate, which means I can't make a pistol. So they do this. Okay. Okay. So what this test is, is a test for the position of the distal radius. And then that tells you what the proximal radius is doing. So for this to have more internal rotation in it, the only way that I can do that is to make this more ERG. Okay. Okay. The forum is going to look short. Okay, because it is technically speaking, it's short. If I twist the radius, it's like when you twist a towel, the two ends of the towel get closer together, right? So if I twist the radius, the radius actually gets shorter, okay? But I can't open my thumb up into ER because radial deviation is actually a turn of the hand into ER. So I can't do this without compensating. So you see, if you supinate your hand as hard as you can, look at your pistol? You see the pistol show up?
forearm pronationradius-ulna mechanicsradial deviationinternal/external rotationdistal radius position