Post-mortem interval

From Infogalactic: the planetary knowledge core
Jump to: navigation, search
Stages of death

Pallor mortis
Algor mortis
Rigor mortis
Livor mortis
Putrefaction
Decomposition
Skeletonization

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]

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, 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. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Survey of Biological Factors Affecting the Determination of the Postmortem Interval. Bautista, Richard. Spring 2012.
  2. 2.0 2.1 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.
  3. 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.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  4. 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.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  5. 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.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  6. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  7. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  8. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  9. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  10. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).