When I was 13 (basically 800 years ago mid 90s), I visited my friend in Luxembourg, whose family had moved there temporarily for his dad's job. I slipped on their front steps during an epic super soaker battle (I'd brought the water blasters with me because they weren't sold there) and hurt my lower back. Hours later, when I couldn't sleep, they took me to the ER. I don't recall all the details, but I very clearly remember the doc saying that something was wrong with my sacroliliac (I thought she said it was dislocated, but that may be a false memory). She injected me with a huge needle (to this day, my friend and his family won't tell me how big it was (still not sure why they were all allowed to see this do still a huge needle in my back)) and then physically massaged/shoved things back in place. I was told later that in my home US, docs would never have done that physical manipulation, meaning I'd have recovered in a wheelchair for a while.

Anyway, I just saw you write "sacroliliac" and wanted to share my story about my sacroliliac. Believe it or not, it doesn't come up in conversation often.

sure sure

But dragon tail

It's probably all carbon fiber and gyros, maybe a couple of servos, and likely weighs very little.

Edit: and dragon tail, cone on