A method and a device for bone adjustment in a mammal is presented, wherein a device is implanted in the medullar cavity of a bone in the body of said mammal, said device being a device exerting a force to anchoring devices anchored ins aid bone. The method and device has utility in therapeutic and cosmetic bone adjustments, including the lengthening, reshaping and realigning of bones, for example in the correction of congenital deformations, restorative orthopedic surgery and the like.