ACADEMIA Letters Distinguishing Between Antemortem, Perimortem, and Postmortem Bone Trauma: A Short Primer Ashley Smith, University of Toronto In the modern field of forensic anthropology, forensic anthropologists must begin with a set of remains, and then decipher a large amount of information from them. In particular, the forensic anthropologist must identify the individual, if possible, by determining age, sex, and ancestry of an individual, and then provide a rough estimate as to when that person may have passed. In addition, the forensic anthropologist may also have an additional task, which is to interpret any visible bone traumas found on the remains. When it comes to deciphering skeletal trauma and its importance to a particular case, one of the more important functions of the forensic anthropologist is the detection of the time frame in which that trauma was inflicted; or more precisely, whether that trauma occurred before, during, or after the terminal event (death) [1]. This understanding will assist in determining what exactly transpired in the cause an individual’s demise. Antemortem Trauma Of the three traumatic time-frames (ante-, peri-, and postmortem), the easiest of the traumas to detect are those that occur antemortem [2]. The ease of determining if trauma is antemortem derives from the fact that the fractures, generally, show signs of healing [3]. While healing begins almost immediately after the fracture, evidence of the healing processes can develop as early as one week after the injury [1, 2]. Between weeks one and three, the edges of the fracture will start to become remolded and rounded, and by week six, a bony callus will begin to form [2]. These time frames, however, can only be considered a generality because a variety of factors play into the healing rates, including the overall health and nutritional status of the Academia Letters, July 2021 ©2021 by the author — Open Access — Distributed under CC BY 4.0 Corresponding Author: Ashley Smith, ashleyc.smith@mail.utoronto.ca Citation: Smith, A. (2021). Distinguishing Between Antemortem, Perimortem, and Postmortem Bone Trauma: A Short Primer. Academia Letters, Article 1570. https://doi.org/10.20935/AL1570. 1 injured, location of the fracture, and the severity of the injury [1]. While not pertaining to the event that transpired to cause death, antemortem fractures can and do play a major role in forensic anthropology. They can confirm the identity of an unknown decedent by using radiographic comparisons or, if the fracture was serious enough, through the presence of plates and pins, which have recorded serial numbers that are recorded in medical charts and kept by the manufacturer [1, 4]. Antemortem fractures can also be useful in documenting any history of abuse or accidental trauma [1, 2]. While motivations that may have caused a homicide or the direct reasonings behind a death (i.e. a fall) can never truly be determined through skeletal evidence, a history of abuse, in conjunction with other evidence, could be instrumental in determining whether a “suspicious fall” was accidental or homicide. Perimortem Trauma Perimortem skeletal trauma is the most important in understanding and reconstructing events because occurs around the time of the death event. By accurately understanding trauma patterns, a forensic anthropologist will have a better understanding of how the death event took place [1, 2, 3, 5, and 7]. It should be noted, however, that this category is more often used by an anthropologist than a forensic pathologist. Depending upon the pathologist, traumas in a medical sense are classified as either antemortem or postmortem by whether they were sustained before or after life functions ceased [6]. The distinction between perimortem and antemortem trauma can really be summed up in a singular word—healing [7]. Perimortem fractures contain biomechanics that are present in antemortem fractures, but because of death, the natural healing process never really takes place. In addition to the absence of the evidence of healing, perimortem fractures can be distinguished from those that occur after decomposition because of the same antemortem biomechanics [2]. Green, or “living,” bone tends to be somewhat elastic, having a little bit of “give” when it bends [8]. This elasticity results in the edges of fractures to appear irregular, as opposed to the rather jagged or angled appearance associated with terminal breaks [2]. In addition, because of the elasticity of bone, “butterfly” or triangular fractures can also be created when the pushing force on a bone causes a radiating fracture, which follows the tension stresses exerted when force is applied on the opposite side of the bone. This appearance, however, while more common in green bone, can be seen in postmortem traumas as well [9]. Besides the elasticity of green bone, or possibly because of it, certain types of trauma, such as gunshot wounds and blunt force traumas, will contain radiating fractures as well [1, 2, and 8]. Green bones also have a tendency to splinter and when cut or incised a “curling or uplifting” will also be present [8]. Academia Letters, July 2021 ©2021 by the author — Open Access — Distributed under CC BY 4.0 Corresponding Author: Ashley Smith, ashleyc.smith@mail.utoronto.ca Citation: Smith, A. (2021). Distinguishing Between Antemortem, Perimortem, and Postmortem Bone Trauma: A Short Primer. Academia Letters, Article 1570. https://doi.org/10.20935/AL1570. 2 Postmortem Trauma Postmortem trauma is that which occurs after death and is important for determining what transpired to the remains from the time of death to the time of recovery and afterwards [1]. The differentiation of postmortem traumas are critical in the understanding of whether they were caused intentionally by an individual attempting to conceal his or her crime, as would be the case in dismemberment, or occurred naturally because of plant, animal, and soil activity [6]. The differentiation between perimortem and postmortem is particularly important in cases in which remains are found at the scene of a fire. In those cases, understanding fractures that were caused by heat and those that were otherwise inflicted will help to determine if the fire was set as a means of concealing a homicide, or if the fire itself was the cause of death and was otherwise accidental [10]. Postmortem traumas vary from their peri- and antemortem counterparts in that the biomechanics of the bone have completely changed. Whereas anteand perimortem traumas occur in green, elastic bones which have a somewhat “wet” aspect to them, bones in the postmortem stage tend to be dry and rather brittle [1, 2, 3, 7, and 8]. This process, called plastic deformation, occurs when excessive force is applied to a bone and due to the absence of healing mechanisms, the bone does not remodel and can create a variety of changes, particularly in the fracture patterns of the bones [2, 11]. Where perimortem breaks tend to splinter, postmortem breaks tend to shatter [8]. Postmortem fragments and fractures also tend to be more regular in shape, with straight sharp edges and a lack of evidence of bending [2]. Because of the fact that perimortem fractures exist at deposition, there is also a difference in color between perimortem and postmortem traumas. The existing traumas take on the same color as that of the surrounding bone, while postmortem, a lighter, more natural color will be present [2, 8]. Another source of perimortem/postmortem confusion can arise from gunshot wounds to the skull. The skull, being relatively hollow, can easily be crushed during the postmortem interval, particularly in an anterior-posterior force direction or from a lateral direction [2]. While gunshot trauma might not be confused with actual compression fractures, they can obscure gunshot traumas, making bullet trajectories difficult to discern [2]. The size of force exhorted from a bullet, however, compared to that of compression or crushing forces is much smaller. Gunshot wounds also tend to come with radiating fractures that radiate away from the entry and exit points. By examining for these radiating fractures, the presence of a gunshot wound and the trajectory of the bullet can be ascertained and distinguished from postmortem traumas [2]. In addition, because bullets tend to leave metal fragments, radiographs of the remains might be able to distinguish gunshot wounds if the condition of the bones is such that radiating fractures cannot be distinguished [2]. Academia Letters, July 2021 ©2021 by the author — Open Access — Distributed under CC BY 4.0 Corresponding Author: Ashley Smith, ashleyc.smith@mail.utoronto.ca Citation: Smith, A. (2021). Distinguishing Between Antemortem, Perimortem, and Postmortem Bone Trauma: A Short Primer. Academia Letters, Article 1570. https://doi.org/10.20935/AL1570. 3 Problems While in many cases the differentiation between antemortem, perimortem, and postmortem trauma is relatively straightforward, the identification of true perimortem trauma can be problematic. As listed in the literature, while perimortem trauma is sustained around the time of death, not all of that trauma may be related to the death event itself [1]. In particular, traumas listed as postmortem occur in bone that is denaturalized and dried, but injuries sustained while the bone is still wet but after the death of the individual may be confused with injuries that precipitated the death itself, even if they are unrelated. More importantly, while the bone does eventually dry, the duration of the drying phase is not uniform, but contingent upon many variables including environment, soil content and minerals, water tables, and even the number of bodies found within a grave (in mass graves bodies tend to dry slower than in single graves) [1]. Likewise there can potentially be confusion with antemortem fractures that occur so close to the death event that evidence of healing has not had time to develop. In fact, according to Alison Galloway in her book Broken Bones, “’antemortem’ for the anthropologist requires that some evidence of healing be visible, and therefore injuries that occur well before death, but in which healing is not evident, will be counted as perimortem” [1: 12]. This potentially could result in the misclassification of a trauma as perimortem that is, in fact, the result of an unrelated antemortem trauma, and would force any understanding of the true perimortem death event to be inaccurate. The distinction between antemortem, perimortem, and postmortem injuries can be examined on a microscopic level, however depending upon the condition of the remains, such examinations may not be possible. In addition, the procedure might also be time and cost prohibitive. Conclusions While much of the literature in deciphering bone trauma has been relegated to those three easily distinguishable traits, it seems that not enough has been written, or possibly even studied, about pinpointing the differentiation of and placing an exact timeline on them. The current practice of identifying perimortem trauma is in essence to place that trauma in the death sequence even though such injuries could be unrelated. In the field, functional definition of “perimortem” is “at the time of death,” however the factual definition is a timeframe starting between one and three weeks before death, and ending when the bone has entered the drying phase sometime in the later stages of decomposition [1: 12]. This time frame then can literally be anywhere from weeks, months or even years, thereby making the actual death event but a blip in the perimortem window. By pinpointing and shortening the timespan of Academia Letters, July 2021 ©2021 by the author — Open Access — Distributed under CC BY 4.0 Corresponding Author: Ashley Smith, ashleyc.smith@mail.utoronto.ca Citation: Smith, A. (2021). Distinguishing Between Antemortem, Perimortem, and Postmortem Bone Trauma: A Short Primer. Academia Letters, Article 1570. https://doi.org/10.20935/AL1570. 4 “perimortem,” more accurate knowledge about how an individual died and what injuries precipitated that death would develop. However, while such problems do exist, the knowledge that is gained and used by determining the sequence of traumatic events is nevertheless very important. A collection of antemortem injuries can be indicative of abuse or indicative of an individual who is prone to fracturing injuries. An understanding of fracture timing can be useful in determining what, if any, steps may have been used to conceal a crime, or, in the case of fire and heat related traumas, whether a crime was even committed. In the end, the classification of injuries as antemortem, perimortem, and postmortem is vital in determining how an individual set of remains came to be. References 1. Galloway, A., Symes, S., Haglund, W., and France, D. The Role of Forensic Anthropology in Trauma Analysis. In: Galloway, A, editor. Broken Bones: Anthropological Analysis of Blunt Force Trauma. Springfield, IL: Charles C. Thomas; 1999: 5-31. 2. Ortner, D. Differential Diagnosis of Skeletal Injuries. In: Kimmerle, E and Baraybar, J, editors. Skeletal Trauma: Identification of Injuries Resulting from Human Rights Abuse and Armed Conflict. Boca Raton, FL: CRC Press; 2008: 21-87. 3. Quatrehomme, G. and İşcan, M. Postmortem Skeletal Lesions. Forensic Science International 1997 (89) 155-165. 4. Koot, M., Sauer, N., Fenton, T. Radiographic Human Identification Using Bones of the Hand: A Validation Study. J Forensic Sci 2005; 50(2): 1-6. 5. Mann, R. and Owsley, D. Human Osteology: Key to the Sequence of Events in a Post Mortem Shooting. J Forensic Sci 1992; 37(5): 1386-1392. 6. Symes, S., Williams, J., Murray, E., Hoffman, J., Holland, T., Saul, J., Saul, F., Pope, E. Taphonomic Context of Sharp-Force Trauma in Suspected Cases of Human Mutilation and Dismemberment. In: Haglund, W. and Sorg, M, editors. Advances in Forensic Taphonomy: Method, Theory, and Archaeological Perspectives. Boca Raton, FL: CRC Press; 2002: 403-434. 7. Moraitis, K., and Spiliopoulou, C. Identification and Differential Diagnosis of Perimortem Blunt Force Trauma in Tubular Long Bones. Forensic Science, Medicine, and Pathology Academia Letters, July 2021 ©2021 by the author — Open Access — Distributed under CC BY 4.0 Corresponding Author: Ashley Smith, ashleyc.smith@mail.utoronto.ca Citation: Smith, A. (2021). Distinguishing Between Antemortem, Perimortem, and Postmortem Bone Trauma: A Short Primer. Academia Letters, Article 1570. https://doi.org/10.20935/AL1570. 5 2006 2(4): 221. 8. Sauer, N. The Timing of Injuries and Manner of Death: Distinguishing Among Antemortem, Perimortem, and Postmortem Trauma. In. Reichs, K, editor. Forensic Osteology Advances in the Identification of Human Remains, 2nd ed. Springfield, IL: Charles C. Thomas; 1998: 321-332. 9. Ubelaker, D., and Adams, B. Differentiation of Perimortem and Postmortem Trauma Using Taphonomic Indicators. J Forensic Sci 1995; 40(3): 509-512. 10. Hermann, N., and Bennett, J. The Differentiation of Traumatic and Heat-Related Fractures in Burned Bone. J Forensic Sci 1999; 44(3): 461-469. 11. Griffith, J., Tong, M., Hung, H., Kumta, S. Plastic Deformation of the Femur CrossSectional Imaging. American Journal of Roentgen 2005 (184): 1495-1498 Academia Letters, July 2021 ©2021 by the author — Open Access — Distributed under CC BY 4.0 Corresponding Author: Ashley Smith, ashleyc.smith@mail.utoronto.ca Citation: Smith, A. (2021). Distinguishing Between Antemortem, Perimortem, and Postmortem Bone Trauma: A Short Primer. Academia Letters, Article 1570. https://doi.org/10.20935/AL1570. 6