## Livor Mortis (Post-mortem Hypostasis) **Key Point:** Livor mortis is the purple-red discoloration of dependent body areas caused by gravitational pooling of deoxygenated blood after the heart stops. Initially blanching (pressure-reversible), it becomes fixed (non-blanching) as red blood cells hemolyze and hemoglobin diffuses into surrounding tissues. ### Timeline of Livor Mortis Fixation | Time Interval | Appearance & Characteristics | |---|---| | 0–30 minutes | Faint discoloration; completely blanching with pressure | | 30 minutes–4 hours | Darker purple-red; partially blanching | | **8–12 hours** | **Fully fixed and non-blanching; hemoglobin diffusion complete** | | 12–24 hours | Intense purple-red; fixed; may appear as staining | | 24+ hours | Fades as putrefaction progresses | **High-Yield:** The transition from blanching to fixed livor mortis is a key forensic marker for estimating time since death. Once fixed (8–12 hours), it cannot be displaced by pressure or body repositioning. **Clinical Pearl:** Livor mortis distribution can indicate: - Body position at death (dependent areas show maximum discoloration) - Evidence of body movement post-mortem (if livor pattern does not match final body position) - Asphyxia or CO poisoning (cherry-red discoloration due to carboxyhemoglobin or oxyhemoglobin) **Warning:** Do not confuse the timing of blanching loss with the onset of livor mortis itself. Livor begins within minutes but takes 8–12 hours to become completely fixed and non-blanching. **Mnemonic:** **FIXED LIVOR** = **F**ully established **I**n **X**-hours (8–12) **E**xhibits **D** **L**ack of blanching **I**ndicates **V**ascular **O**xyhemoglobin **R**eleased.
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