#forensics blog

Algor Mortis is the name given to the loss of a body's temperature after death. If the body is found within 24 hours following death it may be possible to use temperature to estimate the time of death provided the following conditions are met:

1. The body has been in a place that has remained at normal room temperature without extreme heat or cold

2. The victim's pre-death temperature was not elevated for example by illness

3. The victim was not wearing clothes that may have insulated the body for example a thermal winter coat

Post-mortem lividity, also known as hypostasis, is the staining visible on the skin of a dead body, this happens when gravity causes the blood to settle after death This occurs across the entire lower side of the body but in places where parts of the body are in contact with a solid object, such as the floor, the flesh compresses and staining does not occur in that area although blanching can be visible. It is recognisable by its distinctive reddish-purple, or sometimes blueish-purple, colouring and is usually visible within an hour of death but more pronounced around 4 hours after death. Within the first 4 hours, these stains are not fixed and if the body is moved the blood will shift and stain the part of the body that becomes lower. Depending on the conditions the body is kept in, these stains become fixed between 8 and 24 hours after death.

Rigor Mortis is the scientific term used to describe the stiffening of the muscles of a body after death. A dead body goes from flaccid/limp muscles to one where all the muscles become contracted and stiff, this causes the entire body to be constricted into a fixed position. The muscles then eventually become limp again.

At normal room temperature, this has a time progression of around 36 hours and three 12 hour stages. The initial stiffening of muscles takes 12 hours, the body remains stiff for 12 hours and then progressively becomes limp over 12 hours.

More precisely, the small muscles in the hands and face are usually the first to stiffen and stiffen during the first 2-6 hours, the larger muscles take longer. The rate of rigor mortis can differ for infants, people with high muscles development such as bodybuilders or where there was extensive muscle use just before death for example a violent struggle.

Rigor mortis can be used to determine death and the determinations are as follows:

If the body feels warm and is flaccid, it has been dead for less than 3 hours

If the body feels warm and is stiff, it has been dead for 3 to 8 hours

If the body feels cold and stiff, it has been dead for 8 to 36 hours