Re: Anyone have an L6 vertebra?
My husband has a L6 vertebra. He has the very occassional lower back/sciatic pain episode. And he has more recently strained his lower back twice after crazy amounts of lifting and straining. Trust me, I gave him a drubbing both times! Otherwise, he is remarkable healthy at 47 and has never had a serious back injusry or problem.
I would guess by your report that they are saying your first sacral bone is actually more of an additional lumbar vertebra than anything else. On the right hand side it looks 'normal' but the left hand side is so lumbar that it actually seems like it might move (articulate) with the rest of your sacrum - and a normal sacrum does not move or articulate as the lumbar vertebrae do.
But as to whether this is the cause of your pain or symptoms - I haven't any idea. Anyway, best of luck - Suzy-Q