Abstract: An internal fixation device particularly useful for securing bone fragments which includes an elongate tubular sleeve for insertion into the medullary canal of the bone fragments to be secured; an elongate shaft movable within the sleeve; and at least two anchoring elements, each having an inner end coupled to the shaft and an outer end aligned with a slot in the sleeve and displaceable radially outwardly therethrough to engage a bone fragment upon the movement of the shaft within the sleeve. The inner ends of the anchoring elements coupled to the shaft are oriented such that the outward displacement of one anchoring element anchors the engaged bone fragment against movement in one longitudinal direction, and the outward displacement of the other anchoring element anchors the engaged bone fragment against movement in the opposite longitudinal direction.