The objective of the present study was to elucidate the characteristic morphological signs of the power saw injuries to human long tubular bones and thereby make possible distinguishing between those inflicted by different types of power jigsaws. The experiments were carried out with the use of the power saws with high-speed reciprocating motion of the blade (power jigsaws and sabre saws). The study was focused on the experimental saw injuries to the human long tubular bones inflicted by the power jigsaws and sabre saws. The mathematical analysis has demonstrated the possibility of determining the properties of the saws and blades employed to inflict the injury based on the morphological and dimensional changes in the long tubular bones. The results of the study indicate that the forensic medical expertise of the injuries inflicted by power saws with high-speed reciprocating motion of the blade based on the morphological and dimensional changes in the long tubular bones makes it possible to identify with a probability of 98.6-99.7% both the construction and the size of the instrument used for sawing.