View source for Post-mortem interval

{{short description|Time that has elapsed since a person has died}}
{{About|forensic science|Rosicrucian death practices|Rosicrucian Fellowship#Teachings}}
{{Signs of death}}
[[File:Postmortem interval changes (stages of death).png|thumb|500px|Timeline of postmortem changes.]]
[[File:Michele_Taylor_-_Forensics_Final_Project_(1).jpg|thumb|Figure 1. Post-mortem phenomena to estimate the time of death.]]
The '''post-mortem interval''' ('''PMI''') is the time that has elapsed since an individual's [[death]].<ref name=":0">{{Cite book |title=Forensic entomology: the utility of arthropods in legal investigations |date=2009 |publisher=Taylor & Francis |editor=Jason H. Byrd |editor2=James L. Castner |isbn=978-0-8493-9215-3 |edition=2nd |location=Boca Raton |oclc=144565878}}</ref> When the time of death is not known, the interval may be estimated, and so an approximate time of death established. Postmortem interval estimations can range from hours, to days or even years depending on the type of evidence present.<ref name=":2">{{Cite book |date=2013-10-08 |editor-last=Pokines |editor-first=James |editor2-last=Symes |editor2-first=Steven A. |title=Manual of Forensic Taphonomy |url=http://dx.doi.org/10.1201/b15424 |doi=10.1201/b15424|isbn=9781439878439 |s2cid=132436926 }}</ref> There are standard medical and scientific techniques supporting such an estimation.<ref name=":1">{{Citation |last=Simmons |first=Tal |title=Post-Mortem Interval Estimation: an Overview of Techniques |date=2017-02-10 |work=Taphonomy of Human Remains: Forensic Analysis of the Dead and the Depositional Environment |pages=134–142 |place=Chichester, UK |publisher=John Wiley & Sons, Ltd |doi=10.1002/9781118953358.ch10|isbn=9781118953358 }}</ref>

==Examination of body and scene of death==
{{details|Stages of death}}
Changes to a body occurring after death ([[post-mortem changes]]) include:<ref name=":1" />

* [[Algor mortis]]: body cooling;
* [[Livor mortis]]: settling of blood in the lowest-placed parts of the body;
* [[Rigor mortis]]: stiffening of limbs.

Conditions at the scene of death affect the estimation of time of death. To ''algor mortis'', ''livor mortis'' and ''rigor mortis'', together with consideration of stomach contents, there needs to be some observation of environmental conditions at the death scene to accurately measure the PMI (Fig. 1).<ref>{{cite book |last1=Dix |first1=Jay |last2=Graham |first2=Michael |title=Time of Death, Decomposition and Identification: An Atlas |date=7 December 1999 |publisher=CRC Press |isbn=978-1-4200-4828-5 |page=1 |url=https://books.google.com/books?id=qxO3Z0um6WMC&pg=PA1 |language=en}}</ref> Factors that can affect the rate of human decomposition are concerned with the particular environment a body has been recovered from.<ref name=":2" /> Bodies can be found anywhere from terrestrial to aquatic environments, each possessing their own variables that can alter interval estimations.<ref name=":3" /> Along with common factors of temperature, humidity and element exposure, [[body habitus]] and clothing are an example of a component that can affect the rate of cooling of the body, and so its rate of decomposition.<ref name=":3" /><ref>{{cite book |title=FBI Law Enforcement Bulletin |date=1973 |publisher=Federal Bureau of Investigation, U.S. Department of Justice |page=12 |url=https://books.google.com/books?id=zutC-X8o_bwC&pg=RA9-PA12 |language=en}}</ref> A very approximate rule of thumb for estimating the postmortem interval is as follows:<ref>{{cite book | last=Senior | first=T | title=Forensic ecogenomics : the application of microbial ecology analyses in forensic contexts | publisher=Academic Press | publication-place=London, United Kingdom San Diego, CA | year=2018 | isbn=978-0-12-809360-3 | oclc=1023028365}}</ref>
*Warm and flaccid: less than 3 hours
*Warm and stiff: 3 to 8 hours
*Cold and stiff: 8 to 36 hours
*Cold and flaccid: More than 36 hours.
Due to significant environmental variations between regions, universal formulas would be ill-suited for this topic in [[forensic science]].<ref>{{Cite journal |last1=Cockle |first1=Diane L. |last2=Bell |first2=Lynne S. |date=2015-08-01 |title=Human decomposition and the reliability of a 'Universal' model for post mortem interval estimations |url=https://www.sciencedirect.com/science/article/pii/S037907381500211X |journal=Forensic Science International |language=en |volume=253 |pages=136.e1–136.e9 |doi=10.1016/j.forsciint.2015.05.018 |pmid=26092190 |issn=0379-0738|url-access=subscription }}</ref>

==Analytical techniques==
There are analytical techniques that can be used to determine the [[wiktionary:post mortem|post-mortem]] interval:<ref name=":1" />

* [[Forensic entomology]]: insect (especially blowfly) activity on the corpse.<ref name=":0" />
* Forensic botany: Plant and soil effects on the process of decomposition.<ref name=":2" />
* [[Forensic pathology]]: Cause of death determination and subsequent postmortem changes<ref name=":3">{{Citation |last1=Sorg |first1=Marcella |title=Advancing Forensic Taphonomy: Purpose, Theory, and Process |date=2001-07-30 |url=http://dx.doi.org/10.1201/9781420058352-3 |work=Advances in Forensic Taphonomy |pages=3–29 |publisher=CRC Press |access-date=2022-04-14 |last2=Haglund |first2=William|doi=10.1201/9781420058352-3 |doi-broken-date=12 July 2025 |isbn=978-0-8493-1189-5 |url-access=subscription }}</ref>
* Ocular changes: vitreous [[chemistry]] composition,<ref>{{cite journal|url=https://www.researchgate.net/publication/280613862|title=A New Model for the Estimation of Time of Death from Vitreous Potassium Levels Corrected for Age and Temperature |first1=B.|last1=Zilg|first2=S.|last2=Bernard|first3=K.|last3=Alkass|first4=S.|last4=Berg|first5=H.|last5=Druid|date=17 July 2015|volume=254|pages=158–166|doi=10.1016/j.forsciint.2015.07.020|pmid=26232848|journal=Forensic Science International|hdl=10616/44849|hdl-access=free}}</ref> [[eye]] structural changes.<ref>{{Cite journal |last1=De-Giorgio |first1=Fabio |last2=Grassi |first2=Simone |last3=d'Aloja |first3=Ernesto |last4=Pascali |first4=Vincenzo L. |date=2021-05-01 |title=Post-mortem ocular changes and time since death: Scoping review and future perspective |url=|journal=Legal Medicine |language=en |volume=50 |article-number=101862 |doi=10.1016/j.legalmed.2021.101862 |pmid=33610931 |s2cid=231988953 |issn=1344-6223}}</ref> 
* State or stage of [[decomposition]]: [[Autolysis (biology)|autolysis]] (process of self-digestion) and [[putrefaction]] (process caused by [[bacteria]] found within the body).<ref>{{Cite journal |last=Butzbach |first=Danielle M. |date=2010-03-01 |title=The influence of putrefaction and sample storage on post-mortem toxicology results |journal=Forensic Science, Medicine, and Pathology |language=en |volume=6 |issue=1 |pages=35–45 |doi=10.1007/s12024-009-9130-8 |pmid=19946767 |s2cid=32152746 |issn=1556-2891}}</ref>

More advanced methods include [[DNA]] quantification,<ref>{{cite journal |pmid=21542228 |year=2011 |last1=Lin |first1=X |last2=Yin |first2=YS |last3=Ji |first3=Q |title=Progress on DNA Quantification in Estimation of Postmortem Interval |volume=27 |issue=1 |pages=47–9, 53 |journal=Fa Yi Xue Za Zhi}}</ref> [[infrared spectroscopy]],<ref>{{cite journal |pmid=20707280 |year=2010 |last1=Huang |first1=P |last2=Tuo |first2=Y |last3=Wang |first3=ZY |title=Review on Estimation of Postmortem Interval Using FTIR Spectroscopy |volume=26 |issue=3 |pages=198–201 |journal=Fa Yi Xue Za Zhi}}</ref> and for buried individuals changes in soil composition such as the levels of [[methane]],<ref>{{cite journal | doi=10.1016/j.forsciint.2014.12.002 |year=2015 |last1=Davla |first1=M |last2=Moore |first2=TR |last3=Kalacska |first3=M |last4=LeBlanc |first4=G |last5=Costopoulos |first5=A |title=Nitrous Oxide, Methane and Carbon Dioxide Dynamics from Experimental Pig Graves |volume=247 |pages=41–47 | journal=Forensic Science International |pmid=25544693}}</ref> [[phosphate]]s and [[nitrate]]s,<ref>{{cite journal | doi=10.3997/1873-0604.2004010 |year=2004 |last1=Senos Matias |first1=MJ |title=An Investigation into the Use of Geophysical Methods in the Study of Aquifer Contamination by Graveyards |volume=2 |issue=3 |pages=131–136 | journal=Near Surface Geophysics |bibcode=2004NSGeo...2..131S }}</ref> ninhydrin-reactive nitrogen,<ref>{{cite journal | doi=10.1016/j.forsciint.2009.08.016 |pmid=19773138 |year=2009 |last1=Van Belle |first1=LE |last2=Carter |first2=DO |last3=Forbes |first3=SL |title=Measurement of Ninhydrin Reactive Nitrogen Influx into Gravesoil during Aboveground and Belowground Carcass (''Sus domesticus'') Decomposition |volume=193 |issue=1–3 |pages=37–41 | journal=Forensic Science International}}</ref> [[volatile organic compound]]s,<ref>{{cite journal | doi=10.1016/j.forsciint.2012.06.006 |year=2012 |last1=Vass |first1=A |title=Odor Mortis |volume=222 |issue=1–3 |pages=234–241 | journal=Forensic Science International |pmid=22727573 |url=https://zenodo.org/record/1258965 }}</ref> and water [[Conductivity (electrolytic)|conductivity]],<ref>{{cite journal | doi=10.1111/1556-4029.12802 |pmid=26190264 |year=2015 |last1=Pringle |first1=JK |last2=Cassella |first2=JP |last3=Jervis |first3=JR |last4=Williams |first4=A |last5=Cross |first5=P |last6=Cassidy |first6=NJ |title=Soilwater Conductivity Analysis to Date and Locate Clandestine Graves of Homicide Victims |volume=60 |issue=4 |pages=1052–1061 |journal=Journal of Forensic Sciences|s2cid=12082791 |url=http://eprints.staffs.ac.uk/2166/7/cassella.pdf }}</ref> could also reveal the time of death.

==References==
{{reflist}}

{{Death}}

{{DEFAULTSORT:Post-Mortem Interval}}
[[Category:Medical aspects of death]]
[[Category:Forensic pathology]]