I posted an interesting videoclip where you can watch as the sciatic nerve moves itself in SLR. I did the video with my ultrasound device applying the probe in the posterior part of the tight asking to move only the foot at 70° in SLR. In the video you can recognize the nerve as a big clearer horizontal band that moves right and left (slider) but also inside (tensioner) with a change in shape of the external fibers. You can also watch a change in diameter that means a squeeze of the nerve. In my practice with this kind of procedure I noted different amount of the movement en comparison with different degrees of SLR.
in my opinion this way to check for a real movement could be useful not only for a clinical goal but also within a neurodynamic course to make more real the theory.
greetings from Italy