Feasibility of Contactless 3D Optical Measurement for the Analysis of Bone and Soft Tissue Lesions: New Technologies and Perspectives in Forensic Sciences

In forensic pathology and anthropology, a correct analysis of lesions on soft tissues and bones is of the utmost importance, in order to verify the cause and manner of death. Photographs, videos, and photogrammetry may be an optimal manner of immortalizing a lesion, both on cadavers and skeletal remains; however, none of these can supply a detailed three-dimensional (3D) modeling of the lesion. Up to now, only the use of casts has given us the possibility of studying deep lesions such as saw marks with an accurate and complete 3D reconstruction of bone structure. The present study aims at verifying the applicability of 3D optical contactless measurement for the accurate recording of soft tissue and bone lesions, in order to develop a unique and precise method of registering and analyzing lesions, both in forensic pathology and anthropology. Three cases were analyzed: the first, a car accident with blunt force skin injuries; the second, a murder with blunt force injury to the head applied with a metal rod; the third, a series of sharp force knife and saw lesions on bone. Results confirm that 3D optical digitizing technology is a crucial tool in the immor- talization of wound morphology in the medico-legal context even on ''difficult'' substrates such as cut marks and saw marks on bone. The most important step both at postmortem examination and in anthropological analysis is represented by the in-depth and accurate study of lesions. The analysis of lesions on soft tissues and bone can provide valid information on the shape and size of the tools used during an aggression. Therefore, a detailed 3D study on a toolmark, be it on skin or bone, is crucial. Photographs, although detailed, cannot immortalize the complexity of a lesion in all three dimensions. This may be particularly crucial at the scene of crime, where documentation becomes urgent because several days may go by before the autopsy is performed: this delay may lead to some alteration of the soft tissues and therefore of lesion morphology. Regardless however of whether one needs to immortalize the lesion at the scene of crime or at the autopsy, capturing maximum detail is fundamental. With skeletal remains, a detailed analysis of wounds such as saw marks has been performed up to now by cast- ing only (1). In the past years, the literature has pointed out the use of radio- diagnostic tests, such as scanning electron microscopy (SEM), to improve the quality of detail acquired on the shape and size of tools in bone lesions (2-4), although such analyses cannot be applied to the study of the environment and to larger wounds in