When does rigor mortis typically begin after death?

Rigor mortis, the postmortem stiffening of muscles, typically begins within 2 to 6 hours after death. The process occurs as a chemical change in the muscles, primarily due to the depletion of ATP (adenosine triphosphate) and the buildup of lactic acid. By identifying the onset as occurring around 4 hours after death, this choice aligns with the general timeline accepted in forensics and pathology. This phase progresses to its peak rigidity between approximately 12 to 24 hours post-death, after which it gradually dissipates.

Considering the context of others, while rigor mortis begins shortly after death, an immediate timeline of within 30 minutes is generally too early for significant stiffness to set in. Similarly, although rigor mortis can start following about an hour, the most widely accepted onset is closer to the 4-hour mark, making the choice that aligns with this understanding the most accurate. A mention of rigor mortis within a 12-hour duration pertains more to its endurance rather than the onset, as it peaks well before this timeframe. Thus, recognizing the typical start timing at around 4 hours provides a foundational basis for understanding the rigor mortis process in forensic investigations.