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Algor mortis (), the third
A measured rectal temperature can give some indication of the time of death. Although the
Standards Employed to Determine Time of Death
Estimation of the time since death
(by rectal temperature, C. Henssge, 2004). {{DEFAULTSORT:Algor Mortis Signs of death Latin medical words and phrases Forensic pathology
stage of death
The stages of death of a human being have medical, biochemical and legal aspects. The term taphonomy from palaeontology applies to the fate of all kinds of remains of organisms. Forensic taphonomy is concerned with remains of the human body.
H ...
, is the change in body temperature
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding 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
A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...
), 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 Bennet Dowler (1797-1879) was a physician and physiologist of the United States.
Biography
He was born in Moundsville, Virginia, and received an M.D. from the medical school of the University of Maryland. He settled in Clarksburg, Virginia, whe ...
in 1849. The first published measurements of the intervals of temperature after death were done by John Davy in 1839.
Applicability
A measured rectal temperature can give some indication of the time of death. Although the heat conduction
Thermal conduction is the diffusion of thermal energy (heat) within one material or between materials in contact. The higher temperature object has molecules with more kinetic energy; collisions between molecules distributes this kinetic energy u ...
which leads to body cooling follows an exponential decay
A quantity is subject to exponential decay if it decreases at a rate proportional to its current value. Symbolically, this process can be expressed by the following differential equation, where is the quantity and (lambda
Lambda (; uppe ...
curve, it can be approximated as a linear process: 2 °C during the first hour and 1 °C per hour until the body nears ambient temperature.
The Glaister equation estimates the hours elapsed since death as a linear function
In mathematics, the term linear function refers to two distinct but related notions:
* In calculus and related areas, a linear function is a function whose graph is a straight line, that is, a polynomial function of degree zero or one. For di ...
of the rectal temperature:
:
or
:
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: * Stability or fluctuation of the ambient temperature. * The thickness (i.e.thermal insulation
Thermal insulation is the reduction of heat transfer (i.e., the transfer of thermal energy between objects of differing temperature) between objects in thermal contact or in range of radiative influence. Thermal insulation can be achieved with s ...
value) and body coverage of clothing or similar materials.
* The thermal conductivity
The thermal conductivity of a material is a measure of its ability to heat conduction, conduct heat. It is commonly denoted by k, \lambda, or \kappa and is measured in W·m−1·K−1.
Heat transfer occurs at a lower rate in materials of low ...
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", a highly variable length of time in which the body does not cool.
References
Further reading
* * Karen T. Taylor, "Forensic art and illustration", CRC Press, 2000, , p. 308 * Robert G. Mayer, "Embalming: history, theory, and practice", McGraw-Hill Professional, 2005, , p. 106 * Calixto Machado, "Brain death: a reappraisal", Springer, 2007, , pp. 73–74External links
Standards Employed to Determine Time of Death
Estimation of the time since death
(by rectal temperature, C. Henssge, 2004). {{DEFAULTSORT:Algor Mortis Signs of death Latin medical words and phrases Forensic pathology