## Duration and Modifying Factors of Rigor Mortis **Key Point:** Rigor mortis is NOT permanent. It typically persists for 24–48 hours (range 8 hours to several days) and is abolished by putrefaction. Environmental temperature is the most important modifying factor. ### Timeline and Factors | Factor | Effect on Rigor Mortis | |--------|------------------------| | **High temperature (heat)** | Accelerates onset, shortens duration | | **Low temperature (cold)** | Delays onset, prolongs duration | | **Humidity** | Moist environment shortens duration; dry environment prolongs it | | **Physical activity before death** | Hastens onset (glycogen depletion) | | **Putrefaction** | Abolishes rigor as muscles decompose | ### Duration Pattern 1. **Onset:** 2–6 hours post-mortem (variable) 2. **Peak:** 12 hours 3. **Duration:** 24–48 hours (typical range) 4. **Resolution:** Abolished by putrefaction (usually 3–7 days in temperate climate; longer in cold; shorter in heat) **High-Yield:** High temperature **shortens** rigor mortis duration by accelerating putrefaction. Cold **prolongs** it by slowing decomposition. **Mnemonic:** **HEAT = Hastens Everything And Termination** — heat speeds both onset and resolution of rigor. **Warning:** Do NOT confuse "rigor mortis is accelerated by heat" with "rigor lasts longer in heat." Heat accelerates BOTH onset AND resolution (shortens duration).
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