Do bone elasticity and postmortem interval affect forensic fractographic analyses?

Jessica Skinner, Natalie Langley, Malin Joseph, James Herrick, Robert Brown, Brian Waletzki, Peter Goguen, Loukham Shyamsunder, Subramaniam Rajan

Research output: Contribution to journalArticlepeer-review

Abstract

Forensic fractographic features of bone reliably establish crack propagation in perimortem injuries. We investigated if similar fracture surface features characterize postmortem fractures. Experimentally induced peri- and postmortem fractures were used to assess if fractographic features vary as bone elasticity decreases during the postmortem interval (PMI). Thirty-seven unembalmed, defleshed human femoral shafts from males and females aged 33–81 years were fractured at varying PMIs with a drop test frame using a three-point bending setup and recorded with a high-speed camera. Vital statistics, cause of death, PMI length, temperature, humidity, collagen percentage, water loss, fracture energy, and fractography scores were recorded for each sample. Results showed that fractographic features associated with perimortem fractures were expressed in PMIs up to 40,600 accumulated degree hours (ADH), or 60 warm weather days. Hackle was the most consistently expressed feature, occurring in all fractures regardless of ADH. The most variable characteristics were wake features (78.4%) and arrest ridges (70.3%). Collagen percentage did not correlate strongly with ADH (r = −0.04, p = 0.81); however, there was a strong significant correlation between ADH and water loss (r = 0.74, p < 0.001). Multinomial logistic regression showed no association between fractographic feature expression and ADH or collagen percentage. In conclusion, forensic fractographic features reliably determine initiation and directionality of crack propagation in experimentally induced PMIs up to 40,600 ADH, demonstrating the utility of this method into the recent postmortem interval. This expression of reliable fractographic features throughout the early PMI intimates these characteristics may not be useful standalone features for discerning peri- versus postmortem fractures.

Original languageEnglish (US)
Pages (from-to)757-767
Number of pages11
JournalJournal of Forensic Sciences
Volume68
Issue number3
DOIs
StatePublished - May 2023

Keywords

  • accumulated degree hours
  • bone elasticity
  • bone fractures
  • forensic anthropology
  • forensic fractography
  • perimortem trauma
  • postmortem interval

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Genetics

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