SPEAKER_05 33:30–35:42
Okay. 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? 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 going to 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, 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. 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, look at, you see your pistol? You see the pistol show up? So you got to twist the radius. Can you appreciate that?
forearm pronation/supinationradius mechanicsradial deviationinternal rotationhelical motion