The hazard of sharp force injuries: Factors influencing outcome

Spatial relationships among offender, knife, and victim during slashing attacks: implications for crime scene reconstruction

BACKGROUND

The offender-victim spatial relationship is crucial in reconstructing a crime scene. The study aims to evaluate the spatial relationship of performing slashing attacks on a dummy using a Chinese kitchen knife, and thus to establish a scientific basis for crime scene reconstruction.

METHODS

Twenty-four participants (12 males and 12 females) slashed a dummy's neck or chest using a kitchen knife, and the kinematic data were obtained using a three-dimensional motion capture system. The spatial relationships among offender, knife, and victim during slashing attacks were analyzed.

RESULTS

Slashing distance and occupancy area are significantly influenced by gender (all P < 0.05), with males having higher values than females. Body parts significantly influence bevel angle, offender and victim azimuth angles, slashing distance, relative slashing distance, and occupancy area (all P < 0.01), with slashing the chest resulting in larger values than slashing the neck.

CONCLUSION

Gender and body position significantly influence the spatial relationships of slashing action. Our data indicate that males stand farther away and occupy a larger area during slashing attacks. When the chest is slashed, the wound orientation is more diagonal, the offender's standing position and slashing distance are farther, and the occupancy area is larger compared to the neck. The findings could help identify the spatial relationships among offender, knife, and victim, providing a scientific basis for criminal investigations and court trials.

A probabilistic model for murder weapon identification using stab-marks in human ribs

The aim of this article is to provide a scientific and statistical basis to identify the murder weapon in stabbing cases from the geometric characteristics of the stab-marks left on human ribs. For this purpose, a quantitative predictive model is developed, based on geometric measurements of the stab-mark and its location along the rib. A general method based on Bayesian inference and probabilities is used for the model development, rather than a deterministic model given its inability in certain occasions to identify the murder weapon. Following the process explained in this article to collect the stab-mark information required, the complete probabilistic model exposed attained a high accuracy in the identification of the murder weapon between two macroscopically identical blades with a microscopic alteration in one of them (more than 90% of correct identification is achieved).

Overview of Assault-Induced Trauma Presenting to a Trauma Centre in Oman

Objectives

Assault-induced trauma (AIT) is a public health concern that must be addressed and acknowledged. This study aimed to characterise cases of AIT presenting to Sultan Qaboos University Hospital (SQUH), Muscat, Oman.

Methods

This retrospective descriptive study included patients presenting with AIT to the emergency department of SQUH from January 2007 to December 2018. The data obtained included incidence, patients’ demographics, mode of assault, triaging, management and hospital stay. The data were collected using the hospital’s information system and subsequently analysed.

Results

A total of 268 cases of AIT were identified and 239 fulfilled the study criteria. The highest incidence recorded was in 2018, accounting for 72 cases. The mean incidence of AIT was 20 ± 19 per year. The sample was predominantly comprised of males (82.4%) and Omani citizens (65.3%). Most patients (66.9%) were between the ages of 20 and 39. The most common mode of assault was the use of bodily force (34.7%). Additionally, 18.4% were triaged as red cases. In terms of management, 84.5% of the cohort were treated non-surgically. No incidence of in-patient mortality was recorded.

Conclusion

This study found that the rate of AIT averaged at 20 per year with most of the victims being young males. This was the first study that examined AIT in Oman and its results will aid future research and the estimation of the magnitude of this problem in the community.

Criminological and Medico-legal Aspects in Homicidal and Suicidal Sharp Force Fatalities

The interpretation of sharp force fatality dynamics may be difficult in some cases, but a contribution to analysis of the phenomenon may be provided by case studies. Therefore, the purpose of our study is focused on identifying, in observed sharp force fatalities, reliable parameters that can differentiate a homicidal and suicidal manner of death, with particular reference to criminological parameters. Data derived from sharp force fatality cases in Padua and Venice from 1997 to 2019, anonymized and collected in Excel, included personal, circumstantial, clinical, and psychopathological-criminological data, as well as crime scene investigation, necroscopic, and toxicological data. Statistical analyses were performed using chi-square and Wilcoxon rank-sum tests. Possible predictors of homicide were analyzed by logistic regression. Six parameters (bloodstains distant from the body, clothing lacerations, hesitation/defense wounds, number of injuries, and potential motives) were significantly different in the two groups (p < 0.05). An independent statistical association between potential motives explaining the crime (p < 0.001; OR 27.533) and homicide on multiple logistic regression analysis was highlighted. The absence of clothing lacerations was inversely related to homicide (p = 0.002, OR 0.092). To the best of our knowledge, this is one of very few Italian studies concerning the differential diagnosis between homicidal and suicidal sharp force fatalities. The dynamics of the event is established in most cases by the integrated evaluation of data from crime scene investigation and the autopsy. Nevertheless, in an atypical scenario, a psychopathological-criminological analysis may provide essential elements, and particular attention should be given to the identification of potential explanatory motives.

Sharp Force Homicide in Denmark 1992-2016

Sharp force trauma is a common homicide method. The weapon is typically a knife, which is easily accessible and does not require special skills. We have analyzed all 471 sharp force homicides in Denmark during 1992-2016 with special focus on aspects that are relevant to forensic pathologists, including the distribution of wounds and organ injuries. Most homicides were committed inside with a kitchen knife. The front left thorax was the most common area to be affected by sharp force trauma. In 18.9% of the victims, there was only one sharp injury, the majority on the thorax. The most common trajectory for stab wounds was directly posterior with no deviation to the sides or up/down followed by directly anterior. The heart (including pericardium) and lungs (including hemo- and pneumothorax) had injuries in more than 75% of the victims. 67% of victims were males. Female victims had more sharp force injuries and defense wounds than male victims. Most females were killed in domestic homicides (73.7%), most commonly in partner killings (56.4%). In contrast, many male victims were killed in a setting of nightlife/intoxication (34.0%) most by a friend/acquaintance delivering a few stab wounds. The results clearly show strong sex differences in both victims and offenders. This could be useful for shaping policies and public opinion, and as a route for understanding the developments in interpersonal violence. In the narrow setting of death investigation, our results will provide an evidence-based approach to understanding the injury patterns in sharp force homicide.

Self-Inflicted Stab Wounds: A Single-Center Experience from 2010 to 2016

Despite low mortality rates, self-inflicted stab wounds (SISWs) can result in significant morbidity and often reflect underlying substance abuse and mental health disorders. This study aimed to characterize demographics, comorbidities, and outcomes seen in self-inflicted stabbings and compare these metrics to those seen in assault stabbings. A Level I trauma center registry was queried for patients with stab injuries between January 2010 and December 2015. Classification was based on whether injuries were SISWs or the result of assault stab wounds (ASWs). Demographic, injury, and outcome measures were recorded. Differences between genders, ethnicities, individuals with and without psychiatric comorbidities, and SISW and ASW patients were assessed. Within the SIWS cohort, no differences were found when comparing age, gender, or race, including need for operative intervention. However, patients with psychiatric histories were less likely to have a positive toxicology test on arrival than those without psychiatric histories (22% vs. 0%, P = 0.04). When compared with 460 ASW patients, SISW were older (41 vs. 35, P < 0.001), more likely to be white (92% vs. 64%, P < 0.001), more likely to have a psychiatric history (15% vs. 4%, P < 0.001), require operative intervention (65% vs. 50%, P = 0.008), and be discharged to a psychiatric facility (47% vs. 0.2%, P < 0.001). SISW patients have higher rates of psychiatric illness and an increased likelihood to require operative intervention as compared with ASW patients. This population demonstrates an acute need for both inpatient and outpatient psychiatric care with early involvement of multidisciplinary teams for treatment and discharge planning.

Aggression Using a Knife or Other Sharp Instruments and Oral-Maxillofacial Trauma: Incidence, Risk Factors, and Epidemiologic Trends

PURPOSE

The aim of the present study was to characterize the profile of victims of interpersonal physical violence (IPV) caused by a knife or other sharp instrument, identify the factors associated with maxillofacial trauma, and examine the incidence of maxillofacial trauma over time.

PATIENTS AND METHODS

In a retrospective cohort study, we evaluated 569 medicolegal and social records of IPV victims by knife or other sharp instruments treated at a forensic medicine and dentistry center in Brazil during a 4-year consecutive period. The variables investigated were related to the sociodemographic characteristics of the victims, circumstances of the aggression, and trauma patterns. Descriptive and multivariate statistics through Poisson regression and trend analysis with the creation of polynomial regression models were used.

RESULTS

The cumulative incidence of oral-maxillofacial trauma was 19.3%. The mean age of the victims was 31.29 ± 13.82 years. Cases of trauma affecting more than one region of the face prevailed (45.5%). Based on the final Poisson regression model, unemployed people were more likely to exhibit maxillofacial trauma (relative risk [RR] 1.86; 95% confidence interval [CI] 1.03-3.35; P = .039). In addition, individuals were more likely to experience maxillofacial trauma on Wednesdays (RR 1.85; 95% CI 1.01-3.37; P = .045). The trend analysis revealed a significant increase in oral-maxillofacial injuries over time (P < .05).

CONCLUSIONS

The incidence of oral-maxillofacial trauma was high, and the main factors associated with trauma were the victim's employment status and day of occurrence. Future studies will focus on assessing the effect of maxillofacial trauma on the quality of life and well-being of violence victims.