Why does sitting increase PN pain?

[Lernica]

What are the mechanics of the pain? Is it because an entrapped nerve cannot slide away when you sit (like the buttock muscles do)? Is it because the nerve is inflamed and sitting puts more pressure on the nerve and thus increases the inflammation? Is it (as Pianogal has suggested on another thread) because when sitting, the nerve is stretched? Any answers would be welcome. I realized when trying to explain my condition to family and friends that I don't really know the answer to this most basic question.

Thanks.

[JeanieC]

Lernica,

My understanding is that the nerve is stretched when you sit, if it is entrapped. I remember my surgeon saying that he moved my nerve to where is would "have more slack" in it when I sit and bend.

[Lernica]

So if the nerve is not entrapped, does it move out of the way when you sit?

[RJR]

My understanding from talking to docs and PTs and reading journals: when we move, sit, etc., nerves are supposed to be able to glide thru existing tunnels or passages thru tissue, muscle, ligaments, etc. When a nerve gets entrapped or compressed (by a ligament, for example), it no longer can freely glide with movement, or sitting. Since it can no longer glide, it stretches, causing it to be irritated. And when nerves are constantly irritated, they start firing abnormally and increasingly in frequncy. Our brains interpret this as pain.
RR

[Lernica]

Ahhhh! This makes sense. Thanks, RR.

[Paula]

Does anyone else experience temporary relief while sitting by bringing your feet up/in to sit cross legged position? Nearly impossible to do in a small chair. I have tried to understand how this nerve feel so stretched if my body is in an "L-shape" but not so much if I am in a pretzel. I just can't stay that way very long

[Lernica]

I can sit on large soft chairs with either my feet tucked under my butt, or with my feet curled up to one side. Either way, I am much more comfortable sitting with my feet on the chair rather than the floor. I imagine that this is because with the feet tucked up on the chair, pressure is taken off the perineum.

RR, if the sitting position stretches the nerve, why is sitting on the toilet often pain-free?

[RJR]

From what PT's have told me - the nerve is not "double-crushed" on a toilet. When we sit on a hard surface/chair, one crush is in the sitting position, and the second by the pressure of the surface. Remember, an irritated nerve (eg trapped and can't glide) fires more impulses. Maybe someone has heard better explaination.
RR