Microscopic Pattern of Bone Fractures as an Indicator of Blast Trauma: A Pilot Study.

The assessment of fractures is a key issue in forensic anthropology; however, very few studies deal with the features of fractures due to explosion in comparison with other traumatic injuries. This study focuses on fractures resulting from blast trauma and two types of blunt force trauma (manual compression and running over), applied to corpses of pigs; 163 osteons were examined within forty fractures by the transmission light microscopy. Blast lesions showed a higher percentage of fracture lines through the Haversian canal, whereas in other types of trauma, the fractures went across the inner lamellae. Significant differences between samples hit by blast energy and those runover or manually compressed were observed (p<0.05). The frequency of pattern A is significantly higher in exploded bones than in runover and compressed. Microscopic analysis of the fracture line may provide information about the type of trauma, especially for what concerns blast trauma.

Detection of metal residues on bone using SEM-EDS. Part I: Blunt force injury.

Previous studies have indicated that metal particles remain on bone after sharp force injury or gunshot and that their detection by scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS) could greatly help in tool identification. However, the presence of metal particles on bone surfaces in the context of blunt force trauma has never been assessed experimentally. For this reason the present paper represents an experimental study of the behaviour of metal residues on bone following blunt force injury. Ten fresh sub-adult bovine metatarsal bones were manually cleaned of soft tissues. They were then struck by metal bars (copper, iron or aluminium) on the external surface of the mid-diaphysis. All blunt metal instruments used in this study left a sign in the form of single particles, a smear or a powder-like deposit on the bone surface. The residues of all three metal implements were detected on the bone surface, 0.3-10 mm from the fracture border. The presence of metal particles was confirmed in all samples struck with iron and copper and in two of six aluminium samples; no particles were detected on the negative control. Chemical composition of residues highly corresponded with the composition of applied bars.

Distinguishing between perimortem and postmortem fractures: are osteons of any help?

The distinction between perimortem and postmortem fractures in forensic anthropology is still a frequently unsolved issue. In the present study, we try to verify if there are differences in the pattern of osteon fracturing between fresh and dry bone which could be used for such a diagnosis. Fresh and dry long bones were fractured by a hammer at the mid-shaft perpendicularly to the long axis of the bone and the fracture margins examined under a light microscope as undecalcified sections. Examination of 982 osteons (505 fresh, 477 dry) showed that twice as often the fracture line crosses the osteons as opposed to travelling around them, independently of whether the bone is fresh or dry. Statistical analysis confirmed that there was no significant difference between fresh and dry bone. This seems to imply that osteon fracture pattern cannot help in the diagnosis of perimortem versus postmortem bone fractures. Further research however must be performed concerning fast and slow energy dispersal which may have an influence on the type of fracture inflicted.