Review of the pattern of traumatic limb lesions sustained in cases of hanging.

This retrospective study sought to identify a regular pattern of limb bruising which occurs in association with suicidal or accidental hanging. Following exclusion of cases suspicious for homicide, 82 consecutive cases of hanging from a 10-year period were retrospectively reviewed to identify the pattern of traumatic limb injury in each case. Relevant information such as location, toxicology, and type of suspension was also noted. 72% of the reviewed cases had traumatic limb lesions, the majority of which occurred on the posterior upper limb and the anterior lower limb. Although the distribution of limb injury in our study mirrored that found in the literature, the incidence is much higher than in previous studies (7.4-20%). This could either be due to differences in confounding factors such as intoxication and location of hanging or differences in the practice of recording of limb trauma in hanging between centres. Neither type of suspension nor location of hanging were significantly associated with an increased incidence of traumatic limb injury. Positive toxicology was found to increase the likelihood of sustaining limb injury (p = .044084). In conclusion, the presence of this well documented pattern of traumatic limb lesions in cases of hanging should not always raise suspicion of foul play.

Toward a Predictive Assessment of Stab-Penetration Forces.

Collaborative research between the disciplines of forensic pathology and biomechanics was undertaken to investigate the hyperelastic properties of human skin, to determine the force required for sharp instrument penetration of skin, and to develop a finite element model, which reflects the mechanisms of sharp instrument penetration. These studies have led to the development of a "stab metric," based on simulations, to describe the force magnitudes in stabbing incidents. Such a metric should, in time, replace the crudely quantitative descriptors of stabbing forces currently used by forensic pathologists.

A combined experimental and numerical study of stab-penetration forces.

The magnitude of force used in a stabbing incident can be difficult to quantify, although the estimate given by forensic pathologists is often seen as 'critical' evidence in medico-legal situations. The main objective of this study is to develop a quantitative measure of the force associated with a knife stabbing biological tissue, using a combined experimental and numerical technique. A series of stab-penetration tests were performed to quantify the force required for a blade to penetrate skin at various speeds and using different 'sharp' instruments. A computational model of blade penetration was developed using ABAQUS/EXPLICIT, a non-linear finite element analysis (FEA) commercial package. This model, which incorporated element deletion along with a suitable failure criterion, is capable of systematically quantifying the effect of the many variables affecting a stab event. This quantitative data could, in time, lead to the development of a predictive model that could help indicate the level of force used in a particular stabbing incident.

An investigation into the correlation of knife damage in clothing and the lengths of skin wounds.

In determining the possibility that a specific weapon was responsible for a specific injury it is often valuable to examine the damage marks left on any clothing worn by a victim. Correlating this damage both to the skin and clothing with the dimensions of the suspect weapon (if available) may help in determining these possibilities. In this work four different types of knives were used to produce damage marks on various different fabrics both stretched and loose over skin. Statistically significant differences were found between the length of wound on the skin and the corresponding damage to the fabrics when the fabric was stretched over the skin while no statistically significant differences were observed when the fabric was loose over the skin. This was true for all of the knives examined.