Comparison of macroscopic and microscopic (stereomicroscopy and scanning electron microscopy) features of bone lesions due to hatchet hacking trauma.

This experimental study examined the lesions produced by a hatchet on human bones (tibiae). A total of 30 lesions were produced and examined macroscopically (naked eye) and by stereomicroscopy. 13 of them were also analyzed using scanning electron microscopy. The general shape of the lesion, both edges, both walls, the kerf floor and the extremities were described. The length and maximum width of the lesions were also recorded. The microscopic analysis of the lesions led to the description of a sharp-blunt mechanism. Specific criteria were identified (lateral pushing back, fragmentation of the upraising, fossa dug laterally to the edge and vertical striae) enabling the forensic expert to conclude that a hacking instrument was used. These criteria are easily identifiable using scanning electron microscopy, but can also be observed with stereomicroscopy. Overall, lateral pushing back and vertical striae visible using stereomicroscopy and scanning electron microscopy signal the use of a hacking tool.

Sex determination using the DSP (probabilistic sex diagnosis) method on the coxal bone: Efficiency of method according to number of available variables.

The DSP method (probabilistic sex diagnosis) was applied to100 contemporary coxal bones from elderly individuals of the South of France. Ten variables with a posterior probability greater or equal to a 0.95 threshold were used. There was no statistical difference between right side and left side measurements. There was no mistake for sex assignment but the level of indetermination varied a great deal. It was higher in females than in males. The best combinations were obtained when using all 10 variables, some combination of 9 variables (all except SS or SIS or VEAC) or the first 8 variables. We conclude that the DSP method is of great interest in forensic anthropology, thanks to a very weak possibility of mistake when using the software for sex determination of the coxal bone. The main drawback is the level of indetermination that can be high depending on the available variables.

Positive identification by X-rays bone trabeculae comparison.

Positive (certain, absolute) identification of human remains needs a scientific comparison between ante mortem and post-mortem biologic features, as fingerprint, odontological, radiological or DNA comparisons. X-rays comparison has been extensively used, usually comparing some peculiarities such as outlines of the bones, degenerative evolution or pathological conditions. Trabeculae comparisons are sparsely underlined in the forensic literature. We report on a case of decomposed body where fingerprint, DNA and odontological comparisons were not possible. After dissecting the leg and preparing the bones, comparison of ante mortem and postmortem trabeculae led to a positive identification. It was observed that tens of radiolucencies and radiodensities drawn by the trabeculae were useful for comparison, within a very small part of bone. In the case reported here the positive identity could have been assessed only by the comparison of the first metatarsal. The statement of positive identification needs scientific criteria that will be discussed in this article.