So, five minutes ago, I discovered that s-bend (also known as swan bill) corsets were a thing. Apparently, they were invented in the 1890s by Inès Gaches-Sarraute (a medical doctor) as a healthier alternative to regular v-shaped corsets (that is, corsets designed to give women the desirable v shape at the waist), the idea being that it didn’t put so much pressure on the abdomen. They were all the rage from about 1900 and into the early 1910s.
As for what the the corsets looked like…

So pretty!
Below, you can see the finished effect and how the s-bend got its name.

The straight busque forces the pelvis backwards and the bust forwards. Despite the good doctor/corsetiere’s intentions, the health benefits were minimal, given the extreme strain placed on the back.

And, just like the old-style corset, high fashion often dictated ridiculously tight lacing:

Fortunately, in the 1910s, waist lines rose to pretty much regency height (think Rose in Titanic) and women’s backs and waists were safe for a while. I’d laugh except that, more than a hundred years later, we still torture ourselves for fashion. Stilettos, anyone?