Dynamics constrained by the brace geometry. From the concave side (A), the brace extends from the throcanteric region (a) up to the superior neutral vertebra (b). Therefore, the flexion toward the deformity is opposed. The presence of a free space (c-d) between the iliac crest and the upper vertebral limit favors the spine realignment along the cephalo-caudal axis plane (A). The shape of the concave side without (B) and with the brace (C) shows a remarkable difference between the dynamics of the free and that of the constrained spine.