To Linbin
the answer to that question is no, SLR alone cannot diagnose PID. All slr does is give you a picture of what is going on and possible areas to look. I think you have misread my information. the question is can you diagnose PID accurately and I think so. Because you can clinically reason what level with all ur tests and movements combined. We were discussing true PID and not other related casues from the Wikipedia reference-linkSIJ, pelvis or hip.if you clinically reason those out then something must have thrown your thoughts away from the spine. If for example, you did not think it was any of these(hip etc) then something must tell you its the spine. You say there would be neural sensitivity, I do not disagree but the areas of referral will let you know where it is likely coming from.This is assuming there is a referral of course however combined movements and palpation can help clarify where. where the case becomes hard to discern is if the dural sheath is the only structure irritated, then the spread can be everywhere. on the issue of prone knee bend and SLR, those tests are quite sensitive therefore if you do find anything it rules in a likely PID but not specifically.At no point is it wise to base judgements on these two alone.Asking that question if SLR diagnoses PID is not a very accurate question to ask any physio because am sure everyone knows the answer is no.
Concerning the issue of a prolapse or protrusion, my point is the terminologies are often used for one another but they are two different conditions.in a prolapse disce, the annulus is torn therefore the pain the patient feel as compared to when stretched will be different. At no point have I said a prolapsed disc is subclinical(I dont even know what that means in a clinical context). I think with a prolapsed disc the symptoms are more specific as tension is taken away from the posterior structures that are sensitive and that makes it even easier to diagnose.
I agree with you that Wikipedia reference-linkMRIs and SLRs are not enough to make judgements on a back problem.