Editing Algor mortis

{{Short description|Change in body temperature post mortem}}
{{Use dmy dates|date=August 2022}}
{{Signs of death}}
[[File:Postmortem interval changes (stages of death).png|thumb|500px|Timeline of postmortem changes, with algor mortis represented by red temperature line]]
'''Algor mortis''' ({{ety|la|algor|coldness||mortis|of death}}), the third [[stage of death]], is the change in [[Human body temperature|body temperature]] post mortem, until the ambient temperature is matched. This is generally a steady decline, although if the ambient temperature is above the body temperature (such as in a hot [[desert]]), the change in temperature will be positive, as the (relatively) cooler body equalizes with the warmer environment. External factors can have a significant influence.

The term was first used by [[Bennet Dowler]] in 1849.<ref>{{Cite journal|last=Riess|first=Karlem|title=The Rebel Physiologist|url=http://www.jstor.org/stable/24620836|journal=Journal of the History of Medicine and Allied Sciences|jstor=24620836}}</ref> The first published measurements of the intervals of temperature after death were done by [[John Davy (chemist)|John Davy]] in 1839.<ref>{{Cite book|url=https://archive.org/details/b21517964_0001|page=[https://archive.org/details/b21517964_0001/page/228 228]|title=Researches: Physiological and Anatomical|last=Davy|first=John|date=1839|publisher=Smith, Elder and Company|language=en}}</ref><ref>{{Cite book|title=Estimation of the Time Since Death, Third Edition|last=Madea|first=Burkhard|publisher=CRC Press|year=2015}}</ref>

== Applicability ==
[[File:Glaister equation.svg|thumb|An XY plot of the Glaister equation with values from 37&nbsp;°C to 20&nbsp;°C (a commonly used ambient temperature)]]
A measured rectal temperature can give some indication of the time of death. Although the [[heat conduction]] which leads to body cooling follows an [[exponential decay]] curve, it can be approximated as a linear process: 2&nbsp;°C during the first hour and 1&nbsp;°C per hour until the body nears ambient temperature.

The '''Glaister equation'''<ref>[http://www.fmap.archives.gla.ac.uk/DC403/DC403_page.htm Forensic Medicine Archives Project] University of Glasgow {{webarchive|url=https://web.archive.org/web/20040605013312/http://www.fmap.archives.gla.ac.uk/DC403/DC403_page.htm|date=5 June 2004}}</ref><ref>{{cite book|title=Forensic Medicine|author=Guharaj, P. V.|chapter=Cooling of the body (algor mortis)|year=2003|edition=2nd|pages=61–62|publisher=Longman Orient|location=Hyderabad|url=https://books.google.com/books?isbn=8125024883}}</ref> estimates the hours elapsed since death as a [[linear function]] of the [[rectal temperature]]:

:<math>
(36.9^\circ C - \text{rectal temperature in Celsius})\cdot\frac{6}{5} </math>
or
:<math>
\frac{98.4\,^{\circ}{\rm F} - \text{rectal temperature in Fahrenheit}}{1.5}
</math>
<!-- (98.4&nbsp;°F&nbsp;-&nbsp;[rectal&nbsp;temperature&nbsp;in&nbsp;Fahrenheit])&nbsp;div 1.5 -->

==Variability==
Generally, temperature change is considered an inaccurate means of determining time of death, as the rate of change is affected by several key factors, including:<ref>{{Cite web |url=http://www.crimewatchcanada.com/index.php?option=com_content&view=article&id=79:changes-to-a-body-after-death&catid=41:january-february-2010-issue-76&Itemid=53 |title=Changes to a Body after Death |access-date=2013-05-05 |archive-url=https://web.archive.org/web/20180908062826/http://www.crimewatchcanada.com/index.php?option=com_content&view=article&id=79:changes-to-a-body-after-death&catid=41:january-february-2010-issue-76&Itemid=53 |archive-date=2018-09-08 |url-status=dead }}</ref>
* Stability or fluctuation of the ambient temperature.
* The thickness (i.e. [[thermal insulation]] value) and body coverage of clothing or similar materials.
* The [[thermal conductivity]] of the surface on which a body lies.
* Diseases or drugs which increase body temperature and thereby raise the starting temperature of the corpse at the time of death
* The existence of a "temperature plateau",<ref>{{cite journal|last=Kaliszan|first=M.|title=Verification of the exponential model of body temperature decrease after death in pigs|journal=Experimental Physiology|date=20 May 2005|volume=90|issue=5|pages=727–738|doi=10.1113/expphysiol.2005.030551 |pmid=15944204|s2cid=22096083}}</ref> a highly variable length of time in which the body does not cool.

==References==
{{reflist}}

==Further reading==
* {{cite book|first=Richard|last=Saferstein|year=2004|title=Criminalistics: Introduction to Forensics|edition=8th|publisher=Pearson Prentice Hall|isbn=0-13-113706-9}}
* Karen T. Taylor, "Forensic art and illustration", CRC Press, 2000, {{ISBN|0-8493-8118-5}}, p.&nbsp;308
* Robert G. Mayer, "Embalming: history, theory, and practice", McGraw-Hill Professional, 2005, {{ISBN|0-07-143950-1}}, p.&nbsp;106
* Calixto Machado, "Brain death: a reappraisal", Springer, 2007, {{ISBN|0-387-38975-X}}, pp.&nbsp;73–74

==External links==
* [https://web.archive.org/web/20160816153514/http://instructor.mstc.edu/instructor/mbessett/Criminal%20Investigation%20Theory%20DOCS/Time%20of%20Death.pdf Standards Employed to Determine Time of Death]
* [http://www.forens-med.ru/tools/henssge_en/ Estimation of the time since death] (by rectal temperature, C. Henssge, 2004).

{{Death}}

{{DEFAULTSORT:Algor Mortis}}
[[Category:Signs of death]]
[[Category:Latin medical words and phrases]]
[[Category:Forensic pathology]]