How does rigor mortis affect the muscles after death?

Rigor mortis refers to the postmortem stiffening of the muscles that occurs after death. When an individual dies, the body undergoes a series of biochemical processes. Initially, there is a depletion of ATP (adenosine triphosphate) in the muscle fibers. ATP is crucial for muscle relaxation because it allows myosin, a protein in muscle cells, to detach from actin after muscle contraction. Without sufficient ATP, the myosin heads remain attached to actin, leading to a state where the muscles contract and become stiff.

This rigidity begins a few hours after death and can last for several days, depending on various factors, including ambient temperature and the physical condition of the deceased. Eventually, the stiffness diminishes as the muscles begin to decompose. The phenomenon of rigor mortis is significant in forensic science, as it can provide information regarding the time of death based on the extent and duration of the rigidity.