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

Abstract

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.

Examination of Hacking and Blunt Force Skeletal Trauma

“…Specialized trauma‐inflicting devices have been used in experimentation of many types of trauma. A bone lesion production device was used in research conducted by Alunni et al (15), Alunni‐Perret et al (16,17), and Nogueira et al (18) and consisted of a central piston with an attached hatchet blade. Humphrey et al (19) used a pivoting arm device, which allowed release from multiple angles as well as the ability to switch out the implements.…”

Interpol review of shoe and tool marks 2016-2019

“…The amount of features varied greatly between three [ 42 ] and seventeen [ 46 , 47 ] and also included surface metrology measures [ 45 ]. Lesions were inflicted on fresh bones [ 37 , [42] , [43] , [44] , [45] ], after freezing [ 46 , 47 ] and with maceration [ 138 ].…”

“…Interpreting the conclusions from the different publications is very difficult since there is a lot of variation in methodologies used. Marks are made by hand [ 41 ], more representative for real casework, while other studies produce marks under more controlled circumstances with different machines [ [138] , [139] , [140] ]. Marks are made in fresh bone material, more representative for real casework, while other studies inflict marks into macerated or old bone material.…”

“…An interesting trend from the recent literature, especially in the field of archeology and anthropology is using morphometrics for the analysis and comparison of marks [ 138 , 139 , [141] , [142] , [143] ]. Morphometrics helps in the statistical evaluation of the morphological features of marks and objects and in the comparison of these features.…”

“…The variability of features in hatchet hacking traumas was studied in Nogueira et al. [ 138 ]. A hatchet was used to inflict thirty lesions in total in two macerated human tibiae with a specifically designed device.…”