Hi, this is my first post here

Background:
I had a nerve conduction study done recently. First a technician tested my lower leg with an electrical device (it came back ok), then the doctor came in and inserted a needle beside my spine at L2 and L4. She later wrote in the report that I have "L4 denervation" and that it is likely responisble for my feelings of stinging, stiffness, numbness etc in my lower leg and foot.

Since then I have noticed that I can tell when the stinging will become worse because I first feel it in my si joint- I feel a slight burning there. But I never feel anything right at the spine near L4. And I don't have low back pain though I do have muscle tightness that I can't stretch out- and which is new.

I have to wait literally months to see the neuroligist again to ask questions (Canada), so I am trying to figure this out in the meantime.....[/I]

so here is my question:
if the doctor pierces the L4 nerve above the si joint - just where it exits the spine- and it comes back "denervated", does that mean that the problem is upstream of where she punctured (ie at the root) or could it also indicate that the nerve is being pinched at the si joint (downstream of the puncture point)?


alternatively-
does anyone know of a link on the internet that explains how these studies work in detail? Also, there must be varying degrees of denervation? Would she have that information?

thanx