What is Rigor Mortis?
Rigor Mortis or postmortem stiffness is the stiffness of the muscles and joints of the body after death, usually between one and four days and is a visible sign of death, caused by chemical changes in the muscles that cause stiffness in the muscles of the limbs.
Rigor mortis is one of the well-known taphonomic changes that cause stiffness of the muscle structure. It is important to understand the substance and physiology of rigor mortis.
Causes of Rigor Mortis
After death, chemical changes in muscles result in hardened disease. When a person dies, the body does not get oxygen. As a result, no chemical reactions and exchanges take place. Muscles cannot produce ATP. The actin-myosin fibers remain contracted and the muscle remains taut.
A human corpse that dies in hot weather will undergo chemical changes more quickly than in cold weather. Bodies immersed in ice water for several days do not pass through the critical illness phase. It begins when the body begins to melt.
Occurrence of Rigor Mortis
The sliding filament concept in muscle fibers depends on the conversion of ATP to ADP.
After death the cellular pH drops drastically due to the synthesis of pyruvic and lactic acids due to the lack of respiratory activity in the corpse.
Glycogen depletion due to muscle glycogen dissolution in the absence of oxygen leads to low ATP availability because otherwise ATP would be used to break down the cross-linking of the fibers and therefore the associated stiffness would be altered.
This stiffness is first observed in the targeted hand in small muscle groups extending from 4 h intervals, then approaching larger muscle types within 12 h postmortem resulting in body stiffness. It depends on the decrease in ATP levels at the time of death.
Rigor mortis finds application in the reconstruction of the postmortem period preserving the exact location of the body, reflecting some of the efforts made to move the body according to – the rigidity of the body at the time of discovery and the weather factor.
Stages of Rigor Mortis
This stage is also known as autodigestion and begins immediately after death. Circulation and respiratory function cease immediately after death.
The body cannot get oxygen or remove waste products from the body. This creates an acidic environment in the body that causes the cells to break down.
Small bumps begin to appear on the skin and internal organs. The epidermis begins to relax. Membranes produce enzymes that eat proteins.
Enzymes produced by membranes produce large amounts of gases. Skin pigmentation is decreased by sulfur-containing compounds released by bacteria. In a process called decomposition, microorganisms produce a bad smell.
Applications Of Rigor Mortis Across Different Streams
Rigor mortis plays an important role in the meat industry because starting and resolution are crucial factors in achieving meat tenderness. Cooling the meat immediately allows cold shortening of the meat resulting in meat shrinkage. It is caused by storage of calcium ions from muscle fibers by cold reflexes. It can be treated using electrical stimulation.
It finds a wide application in the forensic science field because it can be used to accurately determine the time of death when the body is rigid at the beginning of the rigged dying process.
Livor mortis is a technique used to determine if the body has been displaced after death before the onset of rigor mortis.
Site temperature is a factor influencing the hard dying process, with the rate and onset of the reaction being faster in warmer conditions to facilitate optimal conditions for the insect reproduction and metabolism processes.
Lower temperatures, on the other hand, slow down this process.
This article provides a detailed overview of what rigor mortis is, its stages and applications. This article deals with what happens to the body after death.
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