A 58-year-old woman is discovered dead in her bedroom in Mumbai. The ambient room temperature is 26°C. On external examination, the forensic pathologist records the following findings: body temperature 24°C, purple-red discoloration over the back and buttocks that does not blanch on pressure, and a body weight of approximately 65 kg. The victim was last seen alive 36 hours ago. Which of the following statements about algor mortis in this case is most accurate?

Explanation

## Algor Mortis: Temperature-Based Time Estimation **Key Point:** Algor mortis is the **progressive cooling of the body after death** toward ambient temperature. It is influenced by multiple variables and provides only an **approximate** estimate of post-mortem interval (PMI), not an exact one. ### Mechanism of Algor Mortis After death: 1. Metabolic heat production ceases 2. Body loses heat through radiation, conduction, convection, and evaporation 3. Body temperature gradually equilibrates with ambient temperature 4. Rate of cooling is **non-linear** — faster initially, then slower as the temperature differential decreases ### Factors Affecting Rate of Cooling | Factor | Effect on Cooling Rate | | --- | --- | | **Ambient temperature** | Warm environment → slower cooling; cold environment → faster cooling | | **Body mass** | Obese/heavier bodies → slower cooling; thin bodies → faster cooling | | **Clothing & bedding** | Insulation → slower cooling; exposed body → faster cooling | | **Humidity** | High humidity → slower evaporative cooling | | **Age & health** | Elderly, sepsis, fever at death → altered baseline temperature | | **Cause of death** | Hyperthermia (e.g., heat stroke) → slower cooling from elevated baseline | **High-Yield:** The **Henssge nomogram** and **Claus formula** are used to estimate PMI from body temperature, but they account for ambient temperature and body weight. No formula gives precision better than ±4–6 hours in optimal conditions. ### Analysis of This Case - **Ambient temperature:** 26°C (warm, tropical) - **Body temperature:** 24°C - **Temperature differential:** 37°C (normal core) − 24°C = 13°C drop - **Body weight:** 65 kg (average adult female) - **Time since last seen:** 36 hours In a warm environment (26°C), the body cools more slowly. A 13°C drop over 36 hours is reasonable for a 65 kg woman in a 26°C room. The body has nearly equilibrated with ambient temperature, consistent with a PMI of 24–36 hours or longer. **Clinical Pearl:** The **fixed livor mortis** (does not blanch) also supports a PMI of >12 hours, which is consistent with the 36-hour interval. **Mnemonic:** **ALGOR-PMI** — **A**mbient temperature, **L**ocation (clothing/insulation), **G**ross body mass, **O**ther factors (humidity, age, cause) all affect **R**ate of cooling. **P**recision is **M**odest (±4–6 hrs), **I**nconsistent across cases. ### Why Algor Mortis Alone Is Unreliable Algor mortis should **never** be used in isolation to determine PMI. It must be correlated with: - Livor mortis (blanching vs. fixed) - Rigor mortis (onset, progression, loss) - Decomposition (skin slippage, discoloration, putrefaction) - Entomological evidence (if applicable) - Circumstantial evidence (last seen alive, discovery time) [cite:Reddy's Forensic Medicine 33e Ch 3]