Rigor Mortis

Rigor Mortis, stiffening of body muscles after death. Rigor mortis occurs because of chemical changes that take place in the muscle tissue beginning shortly after death. Rigidity increases for several hours and may last for several days before the body becomes limp. Emergency medical personnel recognize the onset of rigor mortis as an unmistakable sign that a patient cannot be revived.

Factors such as physical activity immediately prior to death affect the onset and duration of rigor mortis. By taking repeated measurements of the intensity and progression of rigor mortis and using these measurements in conjunction with other factors, experts are able to estimate the approximate time of death.