Forensic pathology
General
Postmortem changes

Author: Lindsey Harle, M.D. (see Authors page)

Revised: 12 January 2017, last major update February 2012

Copyright: (c) 2012-2017, PathologyOutlines.com, Inc.

PubMed search: postmortem changes [title]

Table of Contents
Additional References
Cite this page: Postmortem changes. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/forensicspostmortem.html. Accessed April 25th, 2017.
Livor mortis
  • Also called lividity; pink to purple skin discoloration due to blood settling in dependent portions of the body
  • Areas exposed to pressure will not show lividity, as the blood vessels are mechanically compressed preventing blood flow
  • Begins to develop 1 - 3 hours after death and fully developed by 10 to 12 hours
  • Initially, livor is due to blood settling within vessels, and thus can shift with movement of the body and will blanch with pressure
  • Later, blood will hemolyze and diffuse out of the vascular space; at this point, livor is fixed; it will not shift with movement of the body and is nonblanchable
  • As livor progresses, some bodies show dark purple Tardieu spots in dependent areas, due to ruptured capillaries
  • Livor mortis can be differentiated from a true antemortem contusion by incising the skin - contusions will show extravascular hemorrhage in the subcutaneous tissue
  • In carbon monoxide poisoning, livor is cherry red in color; prolonged refrigeration causes the same color change

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Livor mortis

Tardieu spots

Rigor mortis
  • Stiffening of the body due to postmortem muscle contraction

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Rigor mortis



  • Occurs as ATP is depleted, preventing relaxation of muscle fibers
  • Begins to develop several hours after death; rigor initially develops in the jaw, followed by upper and lower extremities
  • Rigor is fully developed in approximately 6 to 12 hours
  • Rigor dissipates due to decomposition in approximately 36 - 48 hours
  • Infection, terminal seizure, electrocution, strenuous exercise or high body temperature may cause rigor to develop more rapidly
  • In hot weather, rigor dissipates more rapidly; in cold weather, rigor may persist longer
Decomposition
  • Bodies decompose more rapidly in hot environments and slowly in cold environments
  • Autolysis: aseptic breakdown of tissues due to the release of intracellular enzymes

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Autolysis



  • Putrefaction: breakdown of tissue due to bacteria
    • Green discoloration of the lower abdomen, due to overgrowth of colonic bacteria
    • Greenish black discoloration and swelling of the face and neck
    • Reddish brown purge fluid may extrude from the nose and mouth; this should not be confused with blood
    • Gas formation causes diffuse swelling of the body, most noticeable in the abdomen
    • Skin slippage and blistering; hair slippage from the scalp
    • Marbling occurs due to breakdown of hemoglobin within blood vessels
    • Brain becomes partially liquefied
    • Skeletonization: usually takes several weeks

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Marbling

Purge fluid

Skeletonization of head due to maggots



  • Adipocere formation: transformation of body fat to oleic, palmitic, and stearic acids, appears yellow, white, or brown and waxy; rare, and occurs in humid or wet environments
  • Mummification: skin turns yellowish brown or black, becomes dry and leathery; occurs in dry environments