Hyper-Flexible Elbow

Sorry for not having a before and after pic of this one, I find it really hard to keep my elbow straight, as the more pressure I put on it the more it does this naturally! D hates this, it really freaks him out!
Elbows seem to be the most often ridiculously flexible joint, next to fingers, so for once, I actually have some examples of insanely flexible elbows from right here on dA :
vox-abattoir.deviantart.com/ar...
zaadi-iman.deviantart.com/art/...
bkreed.deviantart.com/art/I-Lo...