an expansible device of medical use for thorax specific compression including an applicable framework as a belt around a patient &# 39 ; s thorax . the belt has a front arc and a back arc faced by concave inner sides and connected on both sides of the thorax by a hinge and by an adjustable side closure . the front arc includes a plate that compresses the deformity , and adjustable suspension for keeping both arcs spaced hanged from the shoulders . the belt also includes at least six joined bent plates , each arc being formed by at least three plates the ends of which overlap connecting the plates by a fixer . the compressing plate includes anchorages for associating an equipment for measuring the pressure made in adjusting the closure between the arcs . the invention includes a device , system , and method to treat a thoracic deformity .