[Mechanics of the characteristic geometry of the human spine undergoing vertical pressure].

Since MAGENDIE in 1816, it has been a common assertion in books of Anatomie that curves of the spine increase its strength. This increase in strength has been estimated by a formula attributed to EULER: R = nc2 + 1 in which R is the strength and nc2 stands for the square of the number of curves. Applying the actual law of Euler on the strength of beams submitted to a vertical effort, the authors conclude that strength is increased by about 30% and not multiplied by 10, 16 or even 17 as is often falsely written.