IMPROVEMENTS TO DEVICES FOR FIXING AND CORRECTING DORSAL VERTEBRAE

摘要

The improvements are applicable to devices for fixing and correcting dorsal vertebrae, of the type which comprise a screw head provided with a groove for receiving a rod for the correction and/or fixing of vertebrae, which is fixed by a nut threaded on the screw head; the nut has at its lower edge an asymmetric toothing with attack and drive edges in the proper rod to be fixed, thereby providing for its rapid and efficient fixing as well as for the braking of the upper nut itself. The head of this screw has a reduced and externally threaded apart to receive the fixing nut, the external diameter of the nut not exceeding the external diameter of the enlarged part.