My attention has several times been attracted by discriptions of this apparatus. The paper recently published in the Journal of the American Medical Association so fully sets forth its construction and mode of application that a discussion of its mechanics may not be out of order.
As described by the author, Dr. Charles F. Stillman, of New York, the apparatus acts upon the principle of a spring-lever posterior splint. How does it differ from the older application of this same principle?
Let Fig. 1 represent the new apparatus and Fig. 2 the old. We will first consider its application as a lever. Traction is exerted on the ends of the spine, at a and c, pressure applied to the point of curvature, at b. As in each instance b is the fulcrum of the lever, the pressure at that point will equal the sum of the forces applied