Stages of death
1. Pallor mortis
2. Algor mortis
3. Rigor mortis
4. Livor mortis
In the given image
Algor mortis is the change in body temperature post mortem, until the ambient temperature is matched. This is generally a steady decline, although if the ambient temperature is above the body temperature (such as in a desert), the change in temperature will be positive, as the (relatively) cooler body acclimates to the warmer environment.
As decomposition occurs the internal body temperature tends to rise again
- A general rule of thumb is that the body loses heat at an average of 1.5°-2° F during the first 12 hours after death.
- Rigor mortis develops as the body’s energy source (adenosine triphosphate ATP) is depleted.
- It is most evident first in the smaller muscle groups, such as the jaw, after which rigor mortis typically occurs in the upper extremities and then the lower extremities.
- It first appears approximately 1-2 hours after death.
- Progressive stiffening occurs for approximately 12 hours, persists for approximately 12 hours, then diminishes over the next 12 hours as tissues break down as a result of autolysis and putrefaction.
- It is a settling of the blood in the lower (dependent) portion of the body post mortem, causing a purplish red discoloration of the skin.
- Livor mortis starts in 20–30 minutes, but is usually not observable by the human eye until two hours after death.
- The size of the patches increases in the next 3–6 hours, with maximum lividity occurring between eight and twelve hours after death.
- Decomposition is a process of endogenous autolysis and putrefaction, primarily from intestinal microorganisms.
- The abdomen develops a green discoloration after 24–36 hours, usually in the right lower quadrant first