No, these aren’t medieval torture devices! In an 1848 issue of the British medical journal The Lancet*, Dr. John Bishop describes the history of medical approaches to straightening out spinal deformities. The unifying premise is that the spinal column can be stretched and then heal in its new position.
Dr. Bishop is, as you might hope, skeptical of the value of these treatments. He argues that this flawed understanding of human physiology encourages women in particular to bind their bodies with corsets into unnatural and unhealthy shapes.
*Bishop, John. “On the Causes, Pathology, and Treatment of Deformities in the Human Body.” The Lancet 1.22 (1848): 574-579. Google Books. Web. 11 Nov. 2013.