An intramedullary nail for the fixation of fractures of the proximal femur, with a femur neck screw (10a), installable with a proximal femur nail (1a), into the intramedullary area, by a diagonal bore (7a), running to the longitudinal axis of the femur nail (1a), from the side of the femur nail (1a), and a locking element (16a) with at least one prong (18a) parallel to the axis of the femur neck screw (10a). A positive connection between the locking element (16a) and a groove (8a) in the bore (7a) of the femur nail (1a) forms a twisting lock of the femur neck screw (10a) and, allows for the axial movement of the femur neck screw (10a) in the bore (7a) of the femur nail (1a).