Forensic Taphonomy and Postmortem Interval Lecture Notes

These flashcards cover the key vocabulary and concepts regarding the Postmortem Interval (PMI), human decomposition stages, and forensic science methods as presented in the lecture transcript.

Postmortem Interval (PMI)

Commonly referred to as "time since death," identifies the length of time for which an individual has been deceased until the point of discovery.

Human Decomposition

The physiochemical processes that degrade organic materials, both hard and soft tissues, into their fundamental components, resulting in cellular breakdown and tissue disintegration.

Autolysis

Known as "self digestion," this involves chemical reactions that breakdown cellular membranes, leading to effects such as skin slippage (bullae, "gloving," or "stocking").

Putrefaction

The breakdown of tissues caused by microorganisms, highly correlated with ambient temperature and stimulated by a rapid drop in the body's pH level.

Adipocere

Also called "grave wax," it is a grayish-white substance that develops from the hydrolysis or hydrogenation of lipids through a process known as saponification.

Temperature (in Decomposition)

The most important criterion affecting the rate of decomposition, accounting for $80\%$ of the variability.

Acidic soil

A soil environment ($pH\,3.0-5.5$) dominated by fungal communities where decomposition can occur up to three times faster than in alkaline soil.

Algor mortis

The cooling of the body after death that occurs during the Fresh Stage of decomposition.

Livor mortis

The pooling of the blood due to gravity following death.

Rigor mortis

The stiffening of muscles that begins several hours after death and reaches its peak at $12$ hours.

Marbling

The breakdown of tissue and contamination of blood within the circulatory system, typically associated with an increased acidic environment during the Discoloration Stage.

Active Decomposition Stage

A stage most often associated with bloating, the height of blowfly larval activity, early beetle activity, and an increased release of decomposition fluid.

Advanced Decomposition Stage

A stage involving the purging of fluid through natural orifices (mouth, nose, rectum, genitals), causing body deflation, skin wrinkling, and vegetation death.

Skeletonized Stage

The longest lasting stage of decomposition, marked by at least $50\%$ of the skeleton being exposed.

Total Body Score (TBS)

A scoring method developed by Megyesi et al. (2005) that assigns numerical scores to segments (head and neck, trunk, limbs) to improve decomposition assessment.

Accumulated Degree Days (ADD)

The sum of average daily temperatures in $^{\circ}\text{C}$ calculated backward from the date remains were found to estimate the postmortem interval.

Postmortem Submersion Interval (PMSI)

The estimation of time since death for remains found in water, specifically referring to the ambient water temperature at the depth of the remains.

Forensic Entomology

The study of insects as related to medicolegal investigations, used to estimate PMI, seasonality, geographic origin, and the presence of drugs.

Forensic Botany

The examination of the medicolegal value of plants associated with human remains, used to determine death circumstances, time of year, and previous locations.