A self-locking, multi-pivoted, surgical instrument used for drawing aside the margins of a thoracic incision to permit examination or surgical intervention within the thoracic cavity. It will typically have two interchangeable, pivoted, broad and curved blades (self-adjusting their angle as the instrument is opened) at the distal end and a screw mechanism at the proximal end that, when rotated, forces the two legs of the instrument apart, also maintaining its set position once it has been set. It is made of high-grade stainless steel and comes in various designs and sizes for adult and paediatric patients. This is a reusable device.