What occurs to muscles after 24-36 hours post mortem?

After 24-36 hours post mortem, muscles typically begin to relax due to the breakdown of rigor mortis. Rigor mortis is a post-mortem change that causes the muscles to stiffen as a result of biochemical processes that occur after death. Initially, immediately following death, there is a state of muscular rigidity. However, as time progresses, the biochemical processes that contributed to the stiffness—such as the depletion of ATP (adenosine triphosphate) that is essential for muscle contraction and relaxation—cause the muscle fibers to begin breaking down, leading to a relaxation of the muscles.

This relaxation can be attributed to the decomposition processes starting to take effect, which affect the proteins in the muscles that are responsible for maintaining stiffness. Understanding these physiological changes is critical for those working in forensic science and related fields, as it helps in estimating the time of death and understanding the overall process of decomposition.