“Postmortem Interval?

I’ve received a few emails and comments asking me to explain some of the terms I have used in recent posts. From now on, I’ll try to do a better of job of providing definitions as I use some of the more “technical? terms pertaining to death investigation. I plan on placing any posts that focus specifically on definitions in a new category titled “Body Language? so they can be found easier.

My last post referred to human decomposition and its role in measuring postmortem interval, which is essentially an estimation as to how much time has transpired from the time the person died to the time that it was examined. This estimation is approximate at best, and the accuracy is determined by the number of physiological changes that can be factored into the estimation as well as observations made at the scene of the death. These factors are variable and count on the investigator to rely on past experience in order to offer accurate opinions.

The three most common physiological changes for establishing postmortem interval are algor mortis, livor mortis, and rigor mortis. Algor mortis refers to the rate at which a body cools after death. Livor mortis refers to the presentation of blood as it has settled in the body. Rigor mortis refers to the postmortem stiffening of muscles. Each of these terms will be covered in more detail in subsequent posts.

These changes are easily altered by the conditions of the scene and the dynamics of the body. As such, the progression of these changes can vary greatly from case to case. It is also easier to make accurate calculations on a recent death than on one where a longer postmortem interval is apparent.

Scene conditions are basically observations made at the scene by the investigator. What was the state of dress of the individual? Were they dressed for bed or to go out in public? When was the last time that the mail was checked or the last time the newspaper was brought in? Did the most recent meal appear to be breakfast or dinner? All of these observations help to establish a timeline for the death itself.

Regardless of how many physiological or scene factors exist, the estimation of postmortem interval is just that—an estimation. Television makes it appear as though an investigator can determine time of death much more accurately than is possible in real life. It would be a gross misrepresentation of knowledge for someone to actually state unequivocally—as is often done on T.V.—that a death occurred at a certain time based on almost immediate observations. The only real accurate time of death is when medical personnel are present at the death or when a traumatic death is instantaneous and witnessed by another individual.

A more accurate way to label estimations of postmortem interval is to refer to the final determination as a “Window of Death? or “Window of Time? in which the death most likely occurred. At its most accurate, this window may be as broad as a few hours. Again, the longer the person appears to have been dead, then the longer the “Window of Death? is going to be.

Still, the time of death issue is second only to the cause of death issue when it comes to questions posed to the death investigator. In most cases, the agency investigating the circumstances of the death will present the death investigator with a scenario that they believe occurred and asked whether or not the presentation of physiological changes observed by the investigator match the suspected time line of events. At best, the death investigator is only able to state whether or not the observed changes are consistent or inconsistent with the time line.


2 Responses to “”

  1. 1 Di
    June 8, 2005 at 9:14 pm

    I’d hate to be the one trying to establish a time of death for anyone in my household based on what appears to have been the last meal or when the last newspaper was brought in…

  2. 2 Laura
    September 20, 2006 at 4:05 pm

    (sorry my email’s wierd,Its supposed to be like that..I dont know why…)

    Well to start out, Im about two months away from being 16 and already I have decided that I want to be a coroner. I havent yet started working in the mortuary in my town, but I plan to shadow there to see what it takes and if I can take it. (I can ^__^) I just wanted to say how much use this website is to my personal studies. Im banned from the computer at home so I research different things at school and stuff.. um. thats all really.

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