The invention concerns an intramedullary nail to be inserted into a fractured long bone, for example a femur, comprising: a rod (2) extending between a proximal part (3) and a distal part (4) a tubular sleeve (5) into which said rod (2) is inserted coaxially at least a first pair of expansion means (12) located in the distal part (4) of said rod (2), said expansion means (12) being made of a shape- memory material in order to assume a first configuration of rest in which they are disposed inside recesses in the lateral wall of the nail (1), and a second configuration of use in which said means (12) are located projecting from the lateral wall of the nail (1) slots (55) are present on the tubular sleeve (5) in correspondence with the shape-memory means (12) to allow for the fastening onto the bone when the means assume said second configuration of use where said rod (2) comprises in correspondence with the proximal end (3) a transversal channel (6) for the passage of a stop screw (S), said tubular sleeve (5) comprising a pair of opposite apertures (7a, 7b) placed in alignment with said channel (6) and where the distal part (4) of the rod (2) does not have any through-channel for a screw.
