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Anthropological analysis of extensive rodent gnaw marks on a human skull using post-mortem multislice computed tomography (pmMSCT)

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Abstract

There now lay revealed such a horror as would have overwhelmed us had we not been prepared. Through a nearly square opening in the tiled floor, sprawling on a flight of stone steps so prodigiously worn that it was little more than an inclined plane at the centre, was a ghastly array of human or semi-human bones. Those which retained their collocation as skeletons showed attitudes of panic fear, and over all were the marks of rodent gnawing.

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... Forensic scenes may include indoor cases, where commensal rodent species have access to remains and may also cause soft tissue damage [32,33], and former cemetery remains that were exposed on the surface [8]. Rodents also have been shown to disperse bone [1,14] and to create pseudotrauma [18,[33][34][35][36]. Multiple types of taphonomic changes caused by rodents are pervasive among human remains from forensic scenes, and these require additional research regarding which rodent species have altered a given set of remains and their overall potential for altering them in a given environment [4]. ...
... obs.). Gnawed bones also may provide nutrients such as calcium [5,9,19,20,34,38]. Omnivorous rodents also may gnaw on wet bone, although this behavior leaves a different pattern than dry-bone gnawing [4,5]. ...
Article
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The eastern gray squirrel (Sciurus carolinensis) is known to gnaw on bone and thus has the potential to affect terrestrial surface remains in forensic scenes throughout its extensive geographic range in North America and other places in the world where it has been introduced. To determine the timing, extent, and characteristics of gnawing of this rodent species within an urban environment, an initial sample of 305 dry postcranial bones of white-tailed deer (Odocoileus virginianus) were wired to trees for a period of 8 weeks and observed every 2 weeks in multiple sites in Boston, Massachusetts. Squirrel gnawing damage included the typical parallel striations noted for rodents and the loss of epiphyses of long bones, marrow cavity exposure, and sculpting of bone margins, with a cumulative total of 58 out of the original sample of 305 bones (19.0%) having gnawing damage of some kind. When subtracting the bones lost during the experiment without previous gnawing, the cumulative total is 58 out of 271 bones (21.4%). Rodent gnawing can advance rapidly, potentially causing the loss of diagnostic bone features and obscuring previous trauma sites, and researchers should be aware of its effects on exposed skeletal remains.
... The phenomenon of postmortem animal interference with human bodies or their remains may form a substantial part of the taphonomic processes a body undergoes after death and is routinely encountered in forensic practice. Postmortem injuries can be inflicted by all species of animals, irrespective of their size or environmental origin, whether from land, sea, or air (Buschmann et al., 2011;Gapert and Tsokos, 2013). The discrimination between antemortem injury and postmortem artifacts generally presents no difficulties because of the absence of hemorrhage and reddening in the tissue adjacent to the wound margins ( Figure 37) and the lack of any vital reaction microscopically. ...
Chapter
The changes and underlying processes that a human body or its remains undergo after death are complex. As with other biological phenomena, there are many variables influencing postmortem changes. Changes in ambient (environmental) temperature tend to alter the rate, but not the underlying biological mechanisms of postmortem changes. It is not generally possible to draw any definite conclusions concerning the time of death from the appearance of a single postmortem change. This chapter concentrates on the morphology and conditions with which different postmortem changes may present.
... An artifact is a spurious postmortem presentation simulating a finding that may be significant in the course of antemortem events. Artifacts on bones are usually the result of animal scavenging which may be long parallel grooves left by rodents' incisors [6] or gnaw and puncture marks from long pointed canines of carnivores [7]. These are easily confused with gunshot wounds and tool marks of the body dismemberment. ...
Article
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Undertaker’s fracture is an artifact related to poor handling of the corpse characterized by subluxation of the lower cervical spine from tearing of the intervertebral disc at C6-C7 vertebral level. It occurs due to sudden fall of the head over occipital region. An identified male dead body in bloated stage of decomposition with alleged history of drowning was brought for autopsy. After removal of neck and thorax structures, complete separation of the intervertebral disc at two levels corresponding to C6-C7 and T3-T4 vertebral region was noticed. No evidence of antemortem trauma or skeletal pathology was found at autopsy including radiological and microscopic examination. The act of forceful bumping of the head became evident on interrogation from the mortuary undertakers. KEY WORDS: Forensic sciences, forensic pathology, artifact, decomposition, drowning, handling and transportation, intervertebral disc, postmortem skull fracture, sphenoid sinus.
... The phenomenon of postmortem animal interference with human bodies or their remains may form a substantial part of the taphonomic processes a body undergoes after death and is routinely encountered in forensic practice. Postmortem injuries can be inflicted by all species of animals, irrespective of their size or environmental origin, whether from land, sea, or air (Buschmann et al., 2011;Gapert and Tsokos, 2013). The discrimination between antemortem injury and postmortem artifacts generally presents no difficulties because of the absence of hemorrhage and reddening in the tissue adjacent to the wound margins ( Figure 37) and the lack of any vital reaction microscopically. ...
... It is interesting to note the pattern of chewing varied with the substrate in some individuals. The findings are consistent with some authors (26); the animals focused their gnawing on the edges and protruding parts of the baits (except the FOC, which by their size and lack of hardness could easily be gnawed in all its extension without a defined pattern). It was also noted that in the DPW and the FGP, the gnawing went in the same direction as the natural wood grain, apparently to facilitate the bite action. ...
Article
In animal bites, the dental attributes can be fundamental in identifying the marks made by various species on different matrices. Although rodent bite marks have been studied in the context of postmortem interference, little research has used different baits to analyze these marks linking not only specific behavior patterns but also the possibility of structural damage. Twenty mice (Mus musculus) were exposed to different baits to study their bite marks in a controlled model. The known pattern of parallel and multiple grooves has been seen in all baits, but polyvinyl chloride and fiber-optic cable were significantly different between each other and the other baits. Some baits showed patterns of anchorage of the upper incisors and space between the lower incisors when gnawing. This technical note represents a novel model of analysis where veterinarians and/or dentists may be asked to give an opinion on alleged animal bite marks.
... The characteristic marks left by rodent gnawing on dry bone are shallow, parallel striations that often blur together as gnawing proceeds in the same location [6,20]. This type of gnawing is often concentrated on bone margins around which the rodents can fit their mouths, and continued gnawing can obliterate bone processes [23]. The width of the individual markings varies according to rodent incisor size. ...
... Over the past decade, postmortem computed tomography (CT) has become a routine examination in forensic autopsies. Postmortem CT may be used to determine the manner and cause of death [1][2][3] as well as to detect bone abnormalities [4,5], identify human remains [6][7][8], perform postmortem angiography [8][9][10][11], determine live birth in cases of suspected neonaticide [12], examine ingested foreign material [13], and detect pathological conditions using rapid prototyping techniques [14,15]. Multislice computed tomography (msCT) yields sufficient information in terms of spatial resolution and three-dimensional (3D) reconstruction ability for most forensic examinations. ...
Article
Postmortem computed tomography (CT) is now routinely performed in forensic autopsies. Microfocus computed tomography (mfCT) has attracted recent attention because it can provide more detailed information than routine postmortem CT can. This feasibility study evaluated the usefulness of mfCT for examination of the hyoid bone and thyroid cartilage in cases of suspected strangulation, where advanced decomposition precludes detection of petechial hemorrhages and hemorrhages adjacent to fractures. The results show that mfCT was useful for identification of thin fracture lines in the fragile laryngeal structures. We suggest that mfCT should be considered for forensic autopsies in cases of suspected strangulation with advanced decomposition.
Article
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Five cases of postmortem bite-injuries inflicted by rodents are presented (five males between 41 and 89 years; three cases caused by mice, one case by rats, one case of possible mixed rodent activity by rats and mice). The study presents a spectrum of phenomenological aspects of postmortem artifacts due to rodent activity to fresh skin and soft tissue: the majority of the injuries have a circular appearance. The wound margins are finely serrated with irregular edges and circumscribed 1-2 mm intervals within, partly showing protruding indentations up to 5 mm. Distinct parallel cutaneous lacerations deriving from the biting action of the upper and lower pairs of the rodents incisors are diagnostic for tooth marks of rodent origin but cannot always be found. No claw-induced damage can be found in the skin beyond the wound margins. Areas involved in the present study were: exposed and unprotected parts of the body, such as eyelids, nose and mouth (representing moist parts of the face); and the back of the hands. Postmortem rodent activity may occasionally be expected on clothed and therefore protected parts of the body. The phenomenon of postmortem rodent activity to human bodies can be found indoors especially under circumstances of low socioeconomic settings; outdoors this finding is particularly observed among fatalities among homeless people.
Article
Injuries to bodies from animal activity are often postmortem in nature, although differentiating ante- from postmortem tissue damage may be difficult. Presented here is the case of a 73-year-old woman who died of a cerebral infarct. The woman demonstrated postmortem, and probable premortem, injuries resulting from rodent activity. Histological examination of tissues from areas of animal activity revealed a subtle early vital reaction, suggesting that the victim may have been alive during the animal feeding activity. Given the Polish folk legend of Popiel, a ninth-century ruler who was eaten alive by mice, the finding of antemortem injuries due to rodents or other animals could be designated the “Popiel phenomenon.” Histological assessment of such wounds may be a crucial step in determining the timing of injuries, helping to elucidate the chronology of the fatal event, and separating pre- from postmortem wounds. If a vital reaction is detected, it can be assumed that the victim was alive for some time in an incapacitated state prior to death, and that death did not occur rapidly.
Article
Hyperostosis frontalis interna (HFI) is a generalised pathological condition with an unknown etiology and variable clinical association. It is characterized by excess bone growth and manifested on the inner table of the frontal bone, occasionally extending onto the temporals, parietals and the occipital. The etiology of HFI is uncertain: it may be an unknown genetic predisposition, a common environmental exposure, or special metabolic diseases. The purpose of the present study is to report cases of HFI in some osteoarcheological series from Hungary and to emphasize the importance of the investigation of HFI in ancient populations. Twenty out of 803 adults with observable frontal bones exhibited HFI, ranging from early to mid-type, including 15 females and 5 males. Some overgrowths with edges were blending into the endocranial surface, and some were prominently protruding from the surface. Advanced cases of HFI (type C) were observed after age 40-60 years.
Article
Animal scavenging activity can result in production of tooth mark artifacts. Such activity can confound interpretation of skeletal material and the identification process. To date, these topics have received limited attention in the forensic science literature. This study discusses the nature of various animal tooth mark artifacts and typical damage to selected bony elements. This study also assesses survivability of various skeletal elements over time. Two major factors that affect which bones are recovered and the amount of damage are circumstances which shelter remains from animals and human population density of the area where the skeleton is recovered.
Article
We present two cases of nearly total skeletization of the exposed face and neck due to indoor postmortem animal interference and a review of the literature. In the case of a 61-year-old man, inspection of the damaged soft tissue margins revealed serrated edges and parallel cutaneous lacerations caused by rats. In the case of a 40-year-old woman, postmortem examination revealed v-shaped and rhomboid-shaped tunneled wounds in the damaged soft tissue caused by a pit bull terrier. The autopsy in both cases identified natural causes of death. While the morphological feature of postmortem soft tissue artifacts caused by rodents can be ascribed to animal incisors, stab wound-like punctured wounds are characteristic of canine dentition of carnivorous origin. Additional morphological criteria for injuries of carnivorous origin are linear scratch-type abrasions from claws in the vicinity of the injuries. In cases of indoor postmortem animal interference damage is primarily caused to the exposed areas of the body, no self-defense injuries can be found on the deceased's body, only a small amount of blood or the total absence of bloodstains should be expected at the scene, an inquiry of pets living free in the house or wild animals having possible access to the scene should be conducted and rodent excrement found at the scene can give the investigator further information.
Teil 1 Zweite, neubearbeitete und erweiterte Auflage
  • S Berg
  • Leichenzerstörung Leichenzersetzung
  • Editor B Mueller
  • Gerichtliche
Germany e-mail: renegapert@daad-alumni.de; rene.gapert@ucd.ie R. Gapert Human Anatomy Laboratory René Gapert's stay at the Institute of Legal Medicine and Forensic Sciences in Berlin was
  • R Gapert
R. Gapert (&) Á M. Tsokos Institute of Legal Medicine and Forensic Sciences, Charité -University Medicine Berlin, Berlin, Germany e-mail: renegapert@daad-alumni.de; rene.gapert@ucd.ie R. Gapert Human Anatomy Laboratory, UCD School of Medicine and Medical Science, University College Dublin, Dublin, Ireland Acknowledgments Dr. René Gapert's stay at the Institute of Legal Medicine and Forensic Sciences in Berlin was supported by a DAAD Research Scholarship (Deutscher Akademischer Austausch Dienst – German Academic Exchange Service Research Grant A/11/75955).
Gerichtliche Medizin. Teil 1. Tod und Sterben, Leich-enuntersuchung, Spurenuntersuchung, Identifizierung, Todes-ursachen, Verkehrsmedizin. Zweite, neubearbeitete und erweiterte Auflage
  • S Berg
  • Leichenzersetzung
  • Leichenzerstö
Berg S. Leichenzersetzung und Leichenzerstö. In: Mueller B, editor. Gerichtliche Medizin. Teil 1. Tod und Sterben, Leich-enuntersuchung, Spurenuntersuchung, Identifizierung, Todes-ursachen, Verkehrsmedizin. Zweite, neubearbeitete und erweiterte Auflage. Berlin: Springer; 1975. p. 62–106.
  • S Berg
  • Leichenzersetzung
  • Leichenzerstörung
Berg S. Leichenzersetzung und Leichenzerstörung. In: Mueller B, editor. Gerichtliche Medizin. Teil 1. Tod und Sterben, Leichenuntersuchung, Spurenuntersuchung, Identifizierung, Todesursachen, Verkehrsmedizin. Zweite, neubearbeitete und erweiterte Auflage. Berlin: Springer; 1975. p. 62-106.
  • WD Haglund
  • R Rabinovich