A subjective analysis of participants' views in a study of experimental modelling of imposed airway obstruction in infants and children.

Deliberate airway obstruction is a well-recognised form of child abuse and one of the most common causes of death in cases of child homicide. Although classical signs such as petechial haemorrhages can be helpful in raising the suspicion of mechanical asphyxia, they are not always present. Therefore, distinguishing between bruising caused by accidents, medical conditions or non-accidental injury remains challenging. We aimed to characterise bruising patterns which are potentially more consistent with deliberate airway obstruction by means of an experimental modelling study. The first results of our project were previously published and demonstrated that bruising anywhere on the head may be consistent with deliberate upper airway obstruction. In this paper, we present the findings of a questionnaire carried out during the modelling to assess participants' perception of force and consider how variables such as age, use of adjuncts and force distribution may affect bruising patterns in deliberate airway obstruction. Statistical analysis of our results showed that participants felt they were using less force in scenarios involving the infant rather than the child resuscitation dummy as well as when using adjuncts, meaning marks are likely to be more subtle. Therefore, in such cases it is important to examine for other signs of asphyxiation (such as petechiae) and consider the possibility that adjuncts might have been used which could make picking up localised injuries more difficult. Our results also showed that participants often felt force was not distributed evenly across the digits, reporting the greatest force through either the thumb in isolation or the thumb plus another digit in up to nearly 50% of cases. This suggests that just one or two bruises may be consistent with deliberate airway obstruction.

Experimental modelling of imposed upper airway obstruction in infants and children.

The interpretation of injuries to children and infants poses a number of difficulties to any medical practitioner involved in their care or tasked with the investigation their death. This includes differentiating accidental from non-accidental trauma and the consideration of medical factors making a child more prone to injury. Non-fatal but life-threatening upper airway obstruction is unfortunately a well-recognized pattern of abuse which may precede a fatal episode. In this experimental study, we aimed to model theoretical digit marks to the head using infant and young child resuscitation dummies, exposed to various methods of deliberate upper airway obstruction. This work has demonstrated that digit marks can be left anywhere on the head and face. However, the distribution of these marks varies dramatically based on how the airway was obstructed. Moreover, digit marks also appeared to be linked together in fairly reproducible patterns. Given the findings in this study, the identification of one or more fingertip type bruises anywhere on an infant or child's face or scalp, should raise the index of suspicion that the individual may have been subject to deliberate upper airway obstruction. This should prompt healthcare professionals to examine the child for markers of mechanical asphyxia, in order to accurately interpret any inadequately explained bruising to the head and face.

The importance of scene photography in routine coronial practice: Results of an audit with an illustrative case of suspected suicidal fatal air embolism.

Pathologists providing a coronial autopsy service are very reliant on the information, including that concerning the body at the scene, provided prior to the post-mortem examination. This ensures the case is appropriate for a non-forensic autopsy and allows proper interpretation of the pathological and laboratory findings. We present the results of an audit of the extent and accuracy of the information provided (in terms of a set of descriptors), in relation to the body at the scene; whether just the information on the coronial autopsy request form 97a is used, or if it is supplemented with details from the police form 97 and statements from attending officers and scene witnesses. The scene photographs were then reviewed to assess the accuracy of the other information sources and their value to the reporting pathologist. The audit showed that scene photographs are undertaken surprisingly frequently (29.6%) but this was only clear from the coronial request in 22% of referrals. More information was consistently available in the police information for most of the scene descriptors. This was usually accurate, but only partially so, with an average of 19% of relevant features. Viewing the scene photographs was deemed beneficial or essential in 51% and 41.1% of cases. The value of scene photography is then illustrated in a case of suspected suicidal venous air embolism, where subsequent review of the images pointed strongly to the rapidity of death, with minimal blood loss but obvious targeting of a very large varicose saphenous vein in the upper thigh.

The use of dental putty in the assessment of hard surfaces within paved urban areas that may leave defined or patterned marks on bodies.

The identification of a patterned skin or scalp mark at autopsy can provide key forensic evidence in identifying an injury that may have been left by an assailant's footwear. It is also important to consider whether such a mark could alternatively have been left by the deceased coming into forceful contact with a hard surface at the scene of an incident, for example by falling. This study was designed to demonstrate how variable surfaces are within paved urban areas, including those which might leave marks resembling footwear patterns, and to evaluate whether dental putty impression lifting is a practical and effective adjunct to photography in assessing patterned surfaces. Eighteen 'scenes' of approximately 50 m² were assessed for different hard surfaces by photography and by the production of dental putty impression lifts. The number of hard surfaces varied between 4 and 12 per scene, with 90% (122/135) of all hard surfaces deemed likely to leave distinct marking on skin with forceful contact and 46% (62/135) a defined/regular mark potentially similar to a footwear injury (mean = 3.4 per scene). Dental putty proved to be an excellent tool in characterising hard surfaces, producing firm but slightly flexible lifts that can be used in combination with a commercially available inkless footwear impression kit to generate transparencies that help facilitate detailed comparison work. Whenever a potential footwear mark is identified at autopsy, a systematic examination of all hard surfaces at the scene is mandatory, and this process will be significantly strengthened by the use of dental putty.

Homicidal smothering: vital histological confirmation of orofacial injury despite a prolonged post-mortem interval.

Homicidal smothering is the deliberate occlusion of the external airways, usually using the hands, pillows, or bedding. Victims are often those who are unable to resist, such as the young or the old. The limited resistance offered by these individuals may result in a comparative lack of injury. We present a case of a 72-year-old female, found deceased on her bed. The case was initially not considered suspicious and a coronial autopsy was performed. Concerns were subsequently raised and the body remained refrigerated. Six months after the initial examination, an opinion was requested as to whether further examination would be worthwhile to consider allegations of deliberate smothering. Review of the scene photographs showed deviation of the nose, eversion of the upper lip, and suspected intra-oral bruising. A bloodstained pillow was adjacent to the face. At the later autopsy, the body was found to show significant post-mortem deterioration and the facial tissues were mummified. The upper lip was excised and routinely processed for histology, sections showing remarkably good tissue preservation and extensive recent bruising, allowing the suspicious lip injuries in the scene photographs to be safely interpreted. This report illustrates the subtle pathological findings apparent in many of these cases and reinforces the need for thorough external examination and correlation with forensic scene investigation. Histological sampling of suspected injuries can be rewarding, even in the presence of severe post-mortem deterioration.