Yup, my thumbs.Also my brother can twist both his hands 350 without moving his arms, And when he was born they said he wasn't going to be about to walk unless they break his legs and let them he and we never did that and he is 18 and can still walk.
Double-jointed means you have like a 100% chance of arthritis in your 40s lol
I can do thisbut only my left hand is that double jointed or just flexible?and I think my shoulders maybe
I'm Double jointed in my thumbs.Thumb on left shows regular and right shows double joint.