From the Research
Rigor mortis is a complex process that involves the stiffening of the body after death, with its re-establishment occurring up to 20 hours post-mortem, as observed in a study of 67 out-of-hospital cases of sudden death 1. The process of rigor mortis begins within 2-6 hours after death, when calcium ions leak into muscle cells, causing the muscles to contract and stiffen. This process starts in smaller muscles like those in the face and jaw before progressing to larger muscle groups. Some key points to consider about rigor mortis include:
- The timing of rigor mortis can be affected by environmental factors such as temperature, with colder conditions slowing down the process and warmer conditions speeding it up.
- The re-establishment of rigor mortis can occur after mechanical loosening, and its degree can equal or even exceed the initial stiffness, as observed in 21 joints in the study by 1.
- The persistence of rigor mortis can last for several days, with one study finding that it can persist for up to 16 days at a constant low temperature of +4 degrees C 2.
- It is essential to consider rigor mortis alongside other post-mortem changes to accurately estimate the time of death, as it can be influenced by various factors, including the person's physical condition at death and environmental conditions.
- In some cases, muscle stiffening similar to rigor mortis can occur in live patients, particularly those with intense low cardiac output status, high doses of inotropic and vasopressor agents, and likely sepsis, as reported in a case study by 3.