Adiopcere and postmortem interval
Adipocere, also known as grave wax or corpse wax, is a naturally occurring substance that forms in deceased bodies under specific conditions. It results from the hydrolysis of body fat in the presence of moisture and typically requires an anaerobic environment. The formation of adipocere is significant in forensic science as it can aid in estimating the postmortem interval (PMI), although it can also complicate these estimations. This process, known as saponification, resembles soap-making and is influenced by factors such as the body’s fat content and environmental moisture levels. Adipocere is more commonly found in individuals with higher body fat, such as women, infants, and obese persons. Its formation is accelerated by warmth, but extreme temperatures can inhibit the process. Additionally, the presence of adipocere can help preserve facial and anatomical features, providing valuable information for forensic investigations long after death. Understanding the characteristics and conditions of adipocere can be crucial for forensic scientists in their work.
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Adiopcere and postmortem interval
DEFINITION: Naturally occurring substance produced by dead bodies under certain conditions from the hydrolysis of body fat and a sufficient amount of water or moisture.
SIGNIFICANCE: Also called grave wax, corpse wax, and mortuary wax, adipocere is commonly formed by the bodies of human beings or animals with sufficient body fat when they lie under wet or moist conditions. The presence of this substance on a human body may help or hinder forensic scientists in estimating the postmortem interval.
The production of adipocere by a body generally requires an anaerobic environment (that is, one without free oxygen), a sufficient quantity of body fat (that is, adipose containing connective tissue with lipids present), and any of a variety of bacteria that take oxygen away from other compounds and thus assist in the hydrolysis of the fats. The material was first recognized and described in the seventeenth century, when Sir Thomas Browne wrote in Hydriotaphia, Urne Buriall (1658) of encountering the substance while relocating previously buried individuals from an English cemetery. The process of adipocere formation is called saponification, which literally means “soap making” (in times past, soap was made with a combination of animal fat, water, and lye, which produced a grayish-white material that was similar to adipocere in appearance and texture). Because adipose tissue, or body fat, can be either white or brown, adipocere may appear grayish-white or tan in color. It was not until the use of microscopes became widespread during the seventeenth century that scientists began to understand the chemical process of saponification.
Adipocere is an artifact of the decomposition process, and because its formation requires that lipids (fats) be present, it is more commonly seen among animal remains containing comparatively high levels of fat. Among humans, this means that adipocere is found most frequently on the bodies of women, infants, and obese individuals of either sex. In addition, fatter individuals contain more moisture, and fats contain fatty acids that have an affinity to attach to sodium or potassium from the environment. Water assists in this process, and, indeed, adipocere is most often found among tissues that have been kept damp, moist, or even submerged.
It has been suggested that the formation of adipocere on a body may be useful as a guide for forensic scientists in estimating the length of time since death (the postmortem interval, or PMI), much like the appearance of algor, rigor, and livor mortis. However, because adipocere results from a chemical process, the speed with which the substance is formed is temperature-dependent, and, as is true for all other PMI indicators, the rate of formation varies. It appears that the formation of adipocere is speeded up by warmth, but temperature extremes, whether too warm or too cold, impede formation. In addition, because saponification produces a more durable substance than do other processes associated with decomposition, the formation of adipocere can result in a body’s retaining facial and other anatomic features well after death.
Bibliography
Gill-King, Herrell. “Chemical and Ultrastructural Aspects of Decomposition.” In Forensic Taphonomy: The Postmortem Fate of Human Remains, edited by William D. Haglund and Marcella H. Sorg. Boca Raton, Fla.: CRC Press, 1997.
O’Brien, Tyler G., and Amy C. Kuehner. “Waxing Grave About Adipocere: Soft Tissue Change in an Aquatic Context.” Journal of Forensic Sciences 52, no. 2 (2007): 294-301.
Magni, Paola A., et al. "A Practical Review of Adipocere: Key Findings, Case Studies and Operational Considerations from Crime Scene to Autopsy." Journal of Forensic and Legal Medicine, 2021, doi.org/10.1016/j.jflm.2020.102109. Accessed 14 Aug. 2024.
Spitz, Werner U., ed. Spitz and Fisher’s Medicolegal Investigation of Death: Guidelines for the Application of Pathology to Crime Investigation. 4th ed. Springfield, Ill.: Charles C Thomas, 2006.