Stages of death
- Pallor mortis
- Algor mortis
- Rigor mortis
- Livor mortis
- 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