Rigor mortis is a condition that a corpse develops from chemical changes.
Rigor mortis is a Latin expression that can be translated as “stiffness of death.” This is the condition that a corpse acquires from various chemical modifications that occur in the muscles. In everyday speech, it is possible to use the term stiff as a synonym for corpse, precisely as a result of rigor mortis.
When a person dies and their body is exposed to a medium temperature, rigor mortis begins to appear about three hours after death and reaches its maximum peak at twelve hours . At that moment, the muscles are completely rigid , the limbs cannot be flexed and the corpse is very difficult to manipulate. After about twenty-four hours, rigor mortis finally begins to relax, due to the breakdown of the muscles.
Rigor mortis process
The process of rigor mortis begins with a contracture in the smooth muscles, the diaphragm and the heart. The stiffness then begins to become evident in the upper extremities and neck, until it reaches the entire body. Once the process begins to reverse, the rigidity disappears.
To summarize all this information, it is possible to distinguish three phases of the rigor mortis process, which are very beneficial in determining the moment of death:
* establishment : it begins at the same time that rigidity is noticed in the body, which occurs approximately after three hours, as mentioned above, and lasts an average of nineteen hours, at which time rigor mortis reaches its maximum intensity . It is important to note that during this phase it is possible to overcome the rigidity with some force, although it returns if it is not applied for a while;
* state : from the end of the establishment phase, the state phase begins, which lasts about twelve hours. It should be taken into account that during this stage it is not possible to overcome the rigidity without tearing or fracturing the limbs of the corpse;
* resolution : thirty-six hours after the moment of death, muscle rigidity is easy to overcome by applying force and does not occur again. After this phase, cadaveric laxity appears.
Rigor mortis begins to appear about three hours after death.
Useful information for the coroner
Rigor mortis provides very valuable information about death . By analyzing the rigor mortis of a body, it is possible to estimate the date and time of death . This information can be key in the investigation of a crime, for example.
It is also possible to establish a first diagnosis of the death and know the last position that the person adopted at the time of death thanks to the analysis of rigor mortis that a corpse presents.
Why does rigor mortis occur?
Although there are a large number of theories about the reasons why rigor mortis occurs, the only one that is supported by a detailed explanation is the following: after death, the body begins to consume the rest of the adenosine triphosphate (also Known by its acronym ATP , it is a nucleotide that plays an essential role in obtaining cellular energy). As adenosine triphosphate is depleted, phosphoric acid increases, which causes a decrease in pH and acidifies the medium; After the phases described above, putrefaction occurs - caused by bacteria - and becomes alkaline, returning the muscles to their laxity.
The French physiologist and pediatrician Pierre-Hubert Nysten made great contributions to the study of states of cadaveric rigidity, and among them are the following data of interest: in the corpses of the elderly and children, rigidity appears earlier, is less intense and lasts less. than in the rest; If the person was in good physical condition and exercised very frequently, the intensity is greater and also appears later than normal; Violent death brings a rigidity that lasts longer and is more intense.
“Rigor mortis” , finally, is the title of a horror film that was produced in Hong Kong and released in 2013 .