Hamstring

[KnottedYet]

Today, I mentioned that I noticed that crouching helps with the spasms and she said that sounds more like psoas muscle. Lying on the table on my back with my left leg hanging off the side was painful in the "spasm" area, lying on my back rotating both legs (knees bent) side to side was painful in the same area (left side) when rotating knees to the right - both of these she said point to the psoas muscle. She sounds very convinced that this is the problem, and since the exercises do pull the sore area I'm a lot more confident we're on the right track now, too. The only doubt I have is that the tingling didn't sound like a psoas symptom, but she did say that everyone is built differently.

Anyway, I hope I'm finally on track to getting this thing settled down. I'll keep doing the exercises and listening to my body. It sure would be a lot easier if body parts didn't blame each other so darned much!

Psoas muscle is anchored on the 5 lumbar vertebrae. If it is so tight that it is pulling you into an anterior derangement, a tight psoas could indirectly cause tingling. (via what position it forces the vertebrae to take and the corresponding weakening of the disc between them)

The problem with a derangement is that the outer wall of the disc becomes overstretched and weak, and tends to take a blobby shape instead of a nice firm-edged shape. (perhaps overstretched from the tight psoas yanking on the adjoining vertebrae like I mentioned above) Now you have TWO problems: a messed up disc wall that needs to be addressed so it can heal, and a tight psoas. The messed up disc wall is what ultimately causes the tingling in lumbar extension.

But actually, you have THREE problems to address: blobby disc wall, tight psoas, and WHAT THE HECK CAUSED THE PSOAS TO GET TIGHT IN THE FIRST PLACE?

Again, please ask your PT to coach you through lumbar neutral in standing and walking, coach you how to protect and re-shape the disc so the weak blobby area can heal, and analyze the forces your lumbar spine experiences that may have caused the whole business to start in the first place.

(based on what you said about supine lumbar rotation, it could be a lateral relevant derangement rather than an anterior derangement, both can cause tingling in extension. Your PT should be able to figure it out in about 5 minutes and will teach you how to push it back into shape and what to to do keep it there for the 7 days it takes to heal the disc wall.)

ETA: as far as her initial mention of spinal stenosis is concerned: your asymmetrical response to supine lumbar rotation pretty much ruled that out, which is why she didn't pursue it further.