Early Post-Mortem Changes

Introduction

• Topic: Early post-mortem changes after death
• Key Changes: Algor mortis, Rigor mortis, and Liver mortis
• Reminder: Subscribe for more content

Algor Mortis (Post-Mortem Cooling)

• Definition: The body’s temperature begins to fall after death.
• Initial Phase:
  • Body temperature does not fall immediately due to ongoing metabolic processes in still-living tissues.
  • Initial plateau phase lasts about 1 hour.
• Temperature Measurement:
  • Core body temperature can be measured via rectum or sub-hepatic space.
• Phases of Temperature Decline:
  1. Plateau Phase: No decrease in temperature (1 hour post-mortem).
  2. Linear Decrease:
     • 0.4 to 0.6 °C drop per hour for 12 to 16 hours.
  3. Terminal Phase:
     • Another plateau phase after 16 hours; temperature remains above baseline due to bacterial activity.
• Conditions Delaying Temperature Decline:
  • Heat stroke: Initial temperature is higher, delaying the drop.
  • Tetanus, severe muscle contractions, septicemia.

Liver Mortis (Post-Mortem Staining)

• Also Known As: Post-mortem staining, lividity, hypostasis.
• Description: Bluish-purple discoloration in dependent body parts after death.
• Contact Pallor: Areas under pressure do not stain (bony prominences).
• Stages of Liver Mortis:
  1. Initial Phase: Begins in the first 30 minutes.
  2. Confluent Sites: By 4 hours, large stained areas appear.
  3. Fixation: Occurs in 6-8 hours; position at time of death is fixed.
• Secondary Lividity:
  • Occurs when body position is changed before fixation.
  • Example: Supine to prone position changes staining areas.
• Conditions Affecting Liver Mortis:
  • Drowning: Continuous movement prevents normal staining.
  • Severe blood loss: Inadequate blood for staining.
• Color Variations in Staining:
  • Carbon monoxide: Cherry red.
  • Cyanide: Brick red.
  • Nitrites: Reddish brown.
  • Other colors associated with different poisons.

Rigor Mortis (Cadaveric Rigidity)

• Definition: Stiffening of muscles after death.
• Rigor Mortis vs. Cadaveric Spasm:
  • Cadaveric Spasm: Immediate post-mortem muscle contraction.
  • Rigor Mortis: Develops after a time.
• Phases of Rigor Mortis:
  1. Primary Flaccidity: Initial relaxation of muscles.
  2. Onset of Rigor Mortis: Begins 1-2 hours post-death.
  3. Secondary Flaccidity: Muscles relax again after rigidity.
• Mechanism:
  • Calcium leaks into sarcomeres, causing sustained contraction due to lack of ATP.
  • Rigor mortis peaks when ATP levels drop to 15% of normal.
• Nistan Rule:
  • Sequence of rigor mortis onset:
    1. Involuntary muscles (heart).
    2. Eyelids, neck, jaw, face, chest, limbs, fingers, and toes.
• Duration Factors:
  • Prolonged in cooler temperatures (24-48 hours in winter) and shorter in warmer temperatures (18-36 hours in summer).

Summary of Key Changes

• Algor Mortis: Helps determine time since death.
• Liver Mortis: Helps identify position at time of death.
• Rigor Mortis: Aids in estimating time since death and provides insights into the circumstances of death.

Conclusion

• Reminder to subscribe for more forensic content.
• Additional resources and channels available.