Dynamics bound by the geometry of the brace. From the concave side, the brace extends from the throcanteric region (A) upto the superior neutral vertebra (b. Therefore, the flection toward the deformity is opposed. The presence of a free space (c-d) between the iliac crest and the upper vertebral limit favours the spine realignment along the cefalo-caudal axis plane (A). The shape of the concave side without (b) and with the brace (c) shows the remarkable diversity between the dynamics of the free and of bound spine.