Post-mortem interval
This article is about forensic science. For Rosicrucian death practices, see Rosicrucianism#Preservation period after death.
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Pallor mortis |
Post-mortem interval (PMI) is the time that has elapsed since a person has died. If the time in question is not known, a number of medical/scientific techniques are used to determine it. This also can refer to the stage of decomposition of the body.
Types of change after death
Many types of changes to a body occur after death. Some of those that can be used to determine the post mortem interval are:[1][2]
- Algor mortis - body cooling;[1]:16
- Livor mortis - settling of blood in the lowest-placed parts of the body;[1]:15–16
- Rigor mortis - stiffening of limbs;[1]:115
- Forensic entomology - insect (especially blowfly)[2]:2 activity on the corpse;[1]:17
- Vitreous humour changes - eye chemistry;[3]
- State of decomposition - autolysis (process of self digestion) and putrefaction (process caused by bacteria found within the body).[1]:16
Traditional decomposition stages
A person who judges the time of death by the means of decomposition can refer to a simple five-stage process:
- Stage 1: Initial Decay - Bacteria located mainly in the lower intestine begin decomposition, giving a greenish color to the lower abdomen.[1]:17
- Stage 2: Putrefaction - Bacteria grow throughout the body, releasing gases, including cadaverine, which in turn bloat the body and cause unpleasant odor.
- Stage 3: Black Putrefaction - This stage brings further discoloration to the body. The gases from bacterial decay begin to escape, causing strong odor.
- Stage 4: Butyric Fermentation - The internal organs liquefy and the body begins to dry out.
- Stage 5: Mummification - This is the slowest of the five stages. In a hot, dry climate the body may dehydrate, inhibiting bacterial decay; the skin dries to a dark leathery appearance.[1]:17
More advanced methods
More advanced methods include DNA quantification,[4] infrared spectroscopy.[5] and for buried individuals changes in soils such as the levels of methane,[6] phosphates and nitrates,[7] ninhydrin-reactive nitrogen,[8] volatile organic compounds[9] and water conductivity.[10]
References
- 1 2 3 4 5 6 7 8 Survey of Biological Factors Affecting the Determination of the Postmortem Interval. Bautista, Richard. Spring 2012.
- 1 2 Blood, guts, gore and soil: decomposition processes in graves and forensic taphonomic applications. Tibbett, Mark. 2010 19th World Congress of Soil Science, Soil Solutions for a Changing World.
- ↑ Muñoz, JI; Suárez-Peñaranda, JM; Otero, XL; Rodríguez-Calvo, MS; Costas, E; Miguéns, X; Concheiro, L (2001). "A new perspective in the estimation of postmortem interval (PMI) based on vitreous". Journal of Forensic Sciences 46 (2): 209–14. PMID 11305419.
- ↑ Lin, X; Yin, YS; Ji, Q (2011). "Progress on DNA quantification in estimation of postmortem interval". Fa yi xue za zhi 27 (1): 47–9, 53. PMID 21542228.
- ↑ Huang, P; Tuo, Y; Wang, ZY (2010). "Review on estimation of postmortem interval using FTIR spectroscopy". Fa yi xue za zhi 26 (3): 198–201. PMID 20707280.
- ↑ Davla, M; Moore, TR; Kalacska, M; LeBlanc, G; Costopoulos, A (2015). "Nitrous oxide, methane and carbon dioxide dynamics from experimental pig graves". Forensic Science International 247: 41–47. doi:10.1016/j.forsciint.2014.12.002.
- ↑ Senos Matias, MJ (2004). "An investigation into the use of geophysical methods in the study of aquifer contamination by graveyards". Near Surface Geophysics 2 (3): 131–136. doi:10.3997/1873-0604.2004010.
- ↑ Van Belle, LE; Carter, DO; Forbes, SL (2009). "Measurement of ninhydrin reactive nitrogen influx into gravesoil during aboveground and below ground carcass (Sus domesticus) decomposition". Forensic Science International 193: 37–41. doi:10.1016/j.forsciint.2009.08.016.
- ↑ Vass, A (2012). "Odor mortis". Forensic Science International 222: 234–241. doi:10.1016/j.forsciint.2012.06.006.
- ↑ Pringle, JK; Cassella, JP; Jervis, JR; Williams, A; Cross, P; Cassidy, NJ (2015). "Soilwater Conductivity Analysis to Date and Locate Clandestine Graves of Homicide Victims". Journal of forensic sciences 60 (4): 1052–1061. doi:10.1111/1556-4029.12802.
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