1. A surgical instrument, such as an expander, containing elongated cup-shaped articulated blades (300) made of a moldable material, such as plastic or metal, with at least one blade (300) having an inwardly curved circumferential edge (314 ) having a connector line (308) obtained by molding, the circumferential edge (314) having a supporting surface (306) including the outer side (307) of the edge and the inner side (309) of the edge, characterized in that the line (308) connectors created on the outer or inner sides (307, 309) of the supporting surface (306) or between them. 2. The tool according to claim 1, wherein the abutment surface (306) faces the abutment surface (306) of an inwardly curved circumferential edge (314) of the opposite or adjacent blade. 3. The tool according to claim 1, characterized in that the inner and outer sides (309； 307) of the edge are respectively curved inward. 4. A tool according to claim 1, characterized in that the line (308) of the connector lies on the inner side (309) of the edge of the supporting surface (306) or near it. A tool according to claim 1, characterized in that each blade (300) is pivotally mounted on one short side, while the supporting surface extends on the opposite short side of the blade (300) .6. A tool according to claim 1, characterized in that the blade (300) has a circumferential edge (314) curved inward, almost completely surrounding each blade (300) .7. A tool according to claim 1, characterized in that the material of the blade (300) has an almost uniform thickness over its cross section. A tool according to claim 1, characterized in that the size of the outer radius (R1) of the outer side (307) of the edge exceeds the size (T1) of the thickness of the blade (300) .9. A tool according to claim 1, characterized in that the size (T2) of the thickness of the circumferential edge (314) is less than the size (T1) of the thickness of the blade (300) .10.1. Хирургический инструмент, такой как расширитель, соде
