That looks really painful for her spine, by the Holy Grail.
Never understood why that part of a woman’s body keeps getting messed up like that.
Usually artists twist women's bodies like taffy so you can see their tits and ass in the same image, e.g. the so-called boobs and butt pose. But there's no ass visible here, so it seems like the artist was just trying to convey a sense of action and dynamism. It still looks ridiculous though, and the balloon breasts aren't helping.