What is rigor mortis?

Rigor mortis refers to the temporary stiffness that occurs in muscles after death, making option B the correct choice. This physiological phenomenon results from biochemical changes in muscle tissue that occur once the heart stops and circulation ceases. After death, the body's energy stores become depleted, leading to a lack of ATP (adenosine triphosphate) which is essential for muscle relaxation. As ATP levels drop, actin and myosin filaments within muscle cells remain in a contracted state, causing the muscles to stiffen.

Rigor mortis typically begins in the smaller muscles and progresses to larger muscle groups, appearing roughly 2-6 hours post-mortem and usually resolving after 24-48 hours as decomposition progresses and muscle tissue breaks down. This process is significant in forensic science, as the timing and intensity of rigor mortis can help determine the time of death.

Understanding rigor mortis helps illustrate how muscular functions change after death due to chemical and physiological processes, contrasting with concepts such as recovery stages or permanent conditions like muscular dystrophy.