the invention is a sternal retractor comprising a pair of arms which one of them has hinch at the proximal part of it with sternum engaging blades thereon and a curved cross bar on which said arms are disposed such that in use the retractor can open the bottom of the sternum more than the top of the sternum to minimize damage and injury to the upper ribs and numbness which sometimes results in the hands of open chest surgery patients . the retractor also has application for other surgical procedures , as well , for the same general purpose of providing an opening of varying size along the length of an incision .