Interlocking Nailing - The shape of the bone is not uniform. The diameter is different everywhere. A rod of the same size can hold the bone in a line, but the bone remains motionless at the point where the fracture is present. This movement is detrimental to the bone matching process. Therefore, horizontal screws are inserted through the rod and bone to stop such movement, These are called interlocking circuits. This surgery for fracture performed by nails and screws is called interlocking nailing.