Algor mortis (postmortem cooling) occurs at an average rate of approximately how many degrees Fahrenheit per hour in a temperate environment?

Explanation

## Algor Mortis: Rate of Postmortem Cooling **Key Point:** Algor mortis occurs at an average rate of **1.0–1.5°F (0.5–0.8°C) per hour** in a temperate environment (15–20°C ambient temperature). ### Henssge Nomogram & Cooling Rate The rate of body cooling follows a **negative exponential curve**, not linear. The body cools fastest immediately after death and slows as it approaches ambient temperature. ### Factors Affecting Algor Mortis Rate | Factor | Effect on Cooling Rate | |---|---| | **Ambient temperature** | Cold environment → faster cooling; warm environment → slower cooling | | **Body composition** | Obese individuals cool slower (insulation); lean individuals cool faster | | **Cause of death** | Fever/sepsis → body may be warm initially; hypothermia → already cool | | **Clothing/wrapping** | Insulation slows cooling | | **Air circulation** | Wind/ventilation increases cooling rate | | **Body surface area** | Larger surface area → faster heat loss | | **Immersion** | Water conducts heat ~25× faster than air | **High-Yield:** The **Henssge Nomogram** is used to estimate time of death using body temperature, ambient temperature, and body weight. It accounts for the non-linear cooling pattern. **Clinical Pearl:** A body found in water cools approximately **25 times faster** than in air, making time-of-death estimation unreliable in aquatic environments. **Mnemonic: ABCDEF of Algor Mortis Factors** - **A**mbient temperature - **B**ody composition (weight, fat) - **C**lothing/covering - **D**eath cause (fever vs. hypothermia) - **E**nvironment (water vs. air) - **F**resh vs. decomposed **Warning:** Do NOT assume linear cooling. The first 1–2 hours may show a drop of 1.5–2°F, but cooling slows significantly as the body approaches ambient temperature.