A “skin–skull–brain model” for the biomechanical reconstruction of blunt forces to the human head

Thali, Michael J.; Kneubuehl, Beat P.; Dirnhofer, Richard

doi:10.1016/s0379-0738(01)00639-9

Cited by 49 publications

(54 citation statements)

References 11 publications

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“…The need for having a test has involved the construction of advanced mechanical models, e.g. [11], to match a weapon to a crime and to reconstruct trauma. Thali et al reported morphologically reproducible results, and their model also reproduced blunt force injuries to the skin and periost [11].…”

Section: Discussionmentioning

confidence: 99%

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Using Coconuts as a Model for Analysing the Injury Pattern of Cranial Blunt Trauma

Christensen¹,

Jørkov²,

Lynnerup³

2008

TOANTHJ

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Blunt trauma to the head may result in the blunt instrument leaving specific imprints or fracture patterns. Being able to correctly correlate one or more possible blunt instruments with the imprints and fractures of an actual case may be important in police investigations. However, most of our knowledge about blunt instruments and cranial imprints and fracture patterns stems from earlier tests performed on cadavers, or more recently, advanced mechanical and computerbased models. As the former is not feasible ethically, and the latter somewhat demanding in terms of laboratory settings and computer programming. Here we present our results by using a fairly simple model: a coconut shell. Striking a half coconut shell with four different blunt instruments did produce consistent imprinting and fracture patterning, which was also consistent with previously published cases. Also, in a blind trial we were able to correctly exclude one or more blunt instruments as the causative weapon. On the other hand, the blind trial also showed that the coconut is not applicable as a model to positively identify a blunt instrument unless the imprint or fracture pattern has a very characteristic shape.

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Section: Discussionmentioning

confidence: 99%

“…[11], to match a weapon to a crime and to reconstruct trauma. Thali et al reported morphologically reproducible results, and their model also reproduced blunt force injuries to the skin and periost [11]. Another way of matching the weapon to the victim is the use of CT-imaging specifically cranial computed tomography (CT) [7].…”

Section: Discussionmentioning

confidence: 99%

Using Coconuts as a Model for Analysing the Injury Pattern of Cranial Blunt Trauma

Christensen¹,

Jørkov²,

Lynnerup³

2008

TOANTHJ

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“…It would therefore seem that such material would be an obvious choice, however, this point hinges on the extent to which these replicas respond to dynamic impacts in ways that are analogous to real bone. In a series of papers Thali et al [1,2,3,4] claimed that similar replicas produced results that were highly accurate with regard to ballistic and blunt-force trauma, although these studies concentrated largely on simulated soft tissue at bullet entrance and exit points and the general appearance of fracture patterns at a gross scale. Thali et al [1,2,3,4] focused on a small range of modern firearms and a mechanism of blunt trauma, if such samples are viable substitutes for human crania they should hold equal potential for investigations of other mechanisms of injury.…”

Section: Introductionmentioning

confidence: 99%

Fantastic plastic? Experimental evaluation of polyurethane bone substitutes as proxies for human bone in trauma simulations

Smith

James²,

Pover³

et al. 2015

Legal Medicine

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“…In an early study, Lee et al [18] created artificial blunt-force injuries using nineteen cadavers, and assessed these according to frequency, length, and depth of wounding. A more recent study by Thali et al [19] saw the introduction of an artificial skin-skull-brain model consisting of silicone rubber casts, on to which a mass was dropped to create lacerations. Unfortunately, neither the impact forces used, nor quantitative data on the injuries caused were published.…”

mentioning

confidence: 99%

The biomechanical modelling of non-ballistic skin wounding: blunt-force injury

Whittle

Kieser

Ichim

et al. 2007

Forensic Sci Med Pathol

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Knowledge of the biomechanical dynamics of blunt force trauma is indispensable for forensic reconstruction of a wounding event. In this study, we describe and interpret wound features on a synthetic skin model under defined laboratory conditions. To simulate skin and the sub-dermal tissues we used open-celled polyurethane sponge (foam), covered by a silicone layer. A drop tube device with three tube lengths (300, 400, and 500 mm), each secured to a weighted steel scaffold and into which a round, 5-kg Federal dumbbell of length 180 mm and diameter 8 cm was placed delivered blows of known impact. To calculate energy and velocity at impact the experimental set-up was replicated using rigid-body dynamics and motion simulation software. We soaked each foam square in 500 mL water, until fully saturated, immediately before placing it beneath the drop tube. We then recorded and classified both external and internal lacerations. The association between external wounding rates and the explanatory variables sponge type, sponge thickness, and height were investigated using Poisson regression. Tears (lacerations) of the silicone skin layer resembled linear lacerations seen in the clinical literature and resulted from only 48.6% of impacts. Poisson regression showed there was no significant difference between the rate of external wounding for different sponge types (P = 0.294) or different drop heights (P = 0.276). Most impacts produced "internal wounds" or subsurface cavitation (96%). There were four internal "wound" types; Y-shape (53%), linear (25%), stellate (16%), and double crescent (6%). The two-way interaction height by sponge type was statistically significant in the analysis of variance model (P = 0.035). The other two-way interactions; height by thickness and sponge type by thickness, were also bordering on statistical significance (P = 0.061 and P = 0.071, respectively). The observation that external wounds were present for less than half of impacts only, but that nearly all impacts resulted in internal wounds, might explain the observed haematoma formation and contusions so often associated with blunt-force injuries. Our study also confirms the key role of hydrodynamic pressure changes in the actual tearing of subcutaneous tissue. At the moment and site of impact, transferred kinetic energy creates a region of high pressure on the fluid inside the tissue. As a result of the incompressibility of the fluid, this will be displaced away from the impact at a rate that depends on the velocity (or kinetic energy) of impact and the permeability and stiffness of the polymeric foam and skin layer.

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A “skin–skull–brain model” for the biomechanical reconstruction of blunt forces to the human head

Cited by 49 publications

References 11 publications

Using Coconuts as a Model for Analysing the Injury Pattern of Cranial Blunt Trauma

Using Coconuts as a Model for Analysing the Injury Pattern of Cranial Blunt Trauma

Fantastic plastic? Experimental evaluation of polyurethane bone substitutes as proxies for human bone in trauma simulations

The biomechanical modelling of non-ballistic skin wounding: blunt-force injury

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