The incidence of scarring on the dorsum of the hand

When undertaking image comparison of the hand between accused and perpetrator, it is not unusual for scars to be identified on the back of the hand. To investigate the occurrence of scarring in a discreet sample, a database of 238 individuals was examined, and the dorsum of the right and left hands was gridded for each individual. The position, size and type of scar were recorded within each grid. It was found that, in general, males exhibited a higher incidence of scarring than females. However, males were more likely to show scarring on their left hand whereas females were more likely to exhibit scarring on their right hand. Contrary to the literature, scarring was not most prevalent along the borders of the hand but occurred more frequently in association with the index and middle finger corridor regions. Surgical scars were rare as were large scars whereas linear scars smaller than 6 mm were the most frequently identified. Close to half of the sample did not exhibit scarring on one hand. The importance of understanding the pattern of scarring on the back of the hand is discussed in the light of forensic image comparison analysis

The incidence and position of melanocytic nevi for the purposes of forensic image comparison

Expert witness opinion based on the comparison of images has been accepted by UK courts as admissible evidence in relation to issues of identity. Within images of the hand are a multiplicity of anatomical features of different aetiology, incidence and distribution patterns and this includes melanocytic nevi, referred to more colloquially as moles and/or birthmarks. The hand is not a common place for these isolated features to develop and so their presence in this anatomical region has the potential to be useful for issues of identity. The results of this study show that approximately 9 % of individuals in a sample of 476 hands, displayed at least one nevus on the back of their hand and, contrary to the literature, the incidence was found to be greater in females (15 % of female cohort) than males (7 % of male cohort). Almost a third of all nevi identified on the dorsum of the hand were abnormal or dysplastic. The most frequent location for these aggregations of melanocytes was in the central region of the dorsum of the hand or at the base of the index finger. The relevance of nevi identified in the image of a perpetrator’s hand and also on that of a suspect/accused is discussed in relation to the issue of whether the images have originated from the same individual

Focal Spot, Summer 1991

https://digitalcommons.wustl.edu/focal_spot_archives/1058/thumbnail.jp

Evaluation of upper extremity anthropometric measurements in terms of sex estimation

Background: One of the most important and broadest areas of forensic medicine is identification. Among the various parameters used, the most important criterion for identification is to determine the sex of the individual concerned. The aim of the current study was to develop models to determine the sex of subjects in case of forensic situations in which anatomical remains and residues of the upper extremity have to be identified.Methods: The research consisted of university students aged 18-25. Arm, forearm, upper extremity, hand, third finger and palmar length, hand width, wrist width, and wrist circumference measurements from 400 subjects were taken from the right and left upper extremities on the basis of anthropometric points. Models were than developed using logistic regression analysis.Results: The developed models provided valid and reliable sex estimates with high and accuracy rates and low prediction errors.Conclusions: The models are representative for the Turkish population in terms of identification. The study thesis can be regarded as an alternative method when economic or other difficulties are encountered in terms of DNA analysis.

Comparing Machine Learning Classifiers and Linear/Logistic Regression to Explore the Relationship between Hand Dimensions and Demographic Characteristics

Understanding the relationship between physiological measurements from human subjects and their demographic data is important within both the biometric and forensic domains. In this paper we explore the relationship between measurements of the human hand and a range of demographic features. We assess the ability of linear regression and machine learning classifiers to predict demographics from hand features, thereby providing evidence on both the strength of relationship and the key features underpinning this relationship. Our results show that we are able to predict sex, height, weight and foot size accurately within various data-range bin sizes, with machine learning classification algorithms out-performing linear regression in most situations. In addition, we identify the features used to provide these relationships applicable across multiple applications

Sampling methods for the recovery of offender cellular material from victim skin surfaces

Sexual assault can cause major health and welfare issues and is considered a severe and inhuman criminal offence. During an assault, minute quantities of trace DNA can be transferred between a perpetrator, victim and/or crime scene. Transfer of DNA often occurs through strong physical skin-to-skin contact or oral acts resulting in saliva being deposited onto the skin of a victim. Understandably, the skin of a victim can be a critical scene for gathering biological material from the perpetrator to produce a DNA profile, so it is imperative that trace DNA evidence is correctly collected. This literature review aims to address the current research on sampling collection methods available and identify potential problems and factors influencing the recovery of DNA from skin-to-skin or saliva-to-skin contact. Several factors have been identified to potentially influence the recovery of biological material from skin, including, but not limited to, the effect of background DNA and shedder status. Whether or not an individual consistently deposits the same amount of DNA every time, particularly after washing hands, is still an area of constant debate. Nevertheless, background DNA has been found to impact the conclusiveness of a profile, and while it is unavoidable, a sampling method that collects the least quantity of background DNA would be extremely beneficial. There are several sample collection methods available including the single swab, double swab, tape-lift and mini-tape. Unfortunately, the use of adhesive tapes is more common for the recovery of cellular material from textiles, with little research focusing on skin as a target surface. Presently, the double swabbing method is considered the gold standard technique for sampling skin, with numerous studies utilising this procedure. While the idea behind this technique is promising, the support for this method was found to be far from universal. There is a lack of overwhelming support for any single sample collection technique, therefore a new method could be introduced using alcohol wipes. Not only are alcohol wipes pre-moistened making for a faster application, but they are also cheap and easily accessible to medical and healthcare workers. There is a need for a single study to compare all the available and potential collection methods, focusing specifically on the recovery of offender DNA from victim skin

The persistence of epiphyseal scars in the distal radius in adult individuals

The use of radiographic imaging in the estimation of chronological age facilitates the analysis of structures not visible on gross morphological inspection. Following the completion of epiphyseal fusion, a thin radio-opaque band, the epiphyseal scar, may be observed at the locus of the former growth plate. The obliteration of this feature has previously been interpreted as the final stage of skeletal maturation and consequently has been included as a criterion in several methods of age estimation, particularly from the distal radius. Due to the recommendations relating to age estimation in living individuals, accurate assessment of age from the distal radius is of great importance in human identification; however, the validity of the interpretation of the obliteration of the epiphyseal scar as an age-related process has not been tested. A study was undertaken to assess the persistence of epiphyseal scars in adults between 20 and 50 years of age through the assessment of 616 radiographs of left and right distal radii from a cross-sectional population. This study found that 86 % of females and 78 % of males retained some remnant of the epiphyseal scar in the distal radius. The relationships between chronological age, biological sex and the persistence of the epiphyseal scar were not statistically significant. The findings of this study indicate that the epiphyseal scars may persist in adult individuals until at least 50 years of age. No maximum age should therefore be applied to the persistence of an epiphyseal scar in the distal radius