Overview
This lecture covers the stages of death, the legal and physical aspects of determining death, post-mortem changes, and their importance in crime investigations and legal medicine.
Legal Presumption of Death and Survivorship
- Presumption of death occurs after 7 years of unexplained absence, except for succession, which requires 10 years (Article 390, Civil Code).
- Presumption for succession is 4 years if lost at sea, in war, or other perilous conditions (Article 391).
- Survivorship is presumed by age and sex: older under 15, younger over 60, under 15 over 60, male between 15-60, or older if the same sex.
Importance of Establishing Time of Death
- Determines investigation timeline, suspects, and reconstructs the sequence of events.
- Time of death estimation assists in narrowing investigation periods and confirming cause and manner of death.
Stages of Death & Post-Mortem Changes
Immediate Stage (0-2/3 hours)
- Blood circulation stops; no visible body changes.
- Tracking and clouding of cornea appear 30 minutes to 2 hours after death.
- Early retinal vessel segmentation (tracking) visible within 2 hours.
- Skin becomes pale and loses elasticity.
- Gastric contents: light meals remain for 1-3 hours, heavy meals 5-6 hours.
Early Post-Mortem Interval (3-72 hours)
- Rigor mortis: muscle stiffening (starts face, progresses to limbs, complete in 6-8 hours).
- Algor mortis: body cooling, most rapid (15-20°F drop) in first 2 hours.
- Factors delaying cooling: fever, sudden death, obesity, asphyxia, tight clothing, small/non-ventilated rooms.
- Factors accelerating cooling: leanness, extreme age, wasting disease, unclothed bodies, open/well-ventilated spaces.
- Post-mortem caloricity: rise in body temperature due to early putrefactive/infective changes.
- Liver mortis: pooling/discoloration of blood in dependent body areas, appears 3-6 hours after death.
Late Post-Mortem Interval (Putrefaction)
- Begins within 1 hour, includes bloating, marbling of veins, and color changes.
- Progresses through active/advanced decay, skeletonization, and dry remains.
- Maceration occurs in fetuses (softening, no putrefaction).
- Saponification (adipocere) forms from fatty tissue in moist, airless environments.
Methods for Estimating Time Since Death
- Use rectal temperature for accuracy.
- Glaister equation: (98.4°F - rectal temp.) ÷ 1.5 = hours since death.
- Newton’s Law of Cooling can be used but requires initial body and ambient temperature.
Key Terms & Definitions
- Presumption of Death — Legal assumption a person is dead after unaccounted absence for a certain period.
- Rigor Mortis — Post-mortem stiffening of muscles due to ATP depletion.
- Algor Mortis — Cooling of body after death.
- Liver Mortis — Discoloration from blood settling in dependent body parts.
- Post-mortem Caloricity — Unusual rise in body temperature after death.
- Putrefaction — Decay and breakdown of body tissue.
- Maceration — Softening of tissues in a fetus post-mortem without putrefaction.
- Saponification (Adipocere) — Conversion of body fat into waxy substance during decomposition.
- Cadaveric Spasm — Instant stiffening of specific muscles at the moment of violent death.
Action Items / Next Steps
- Review Glaister equation and practice calculations using rectal temperature.
- Study identification methods, estimation of height, sex differences in bones, stages of death, and time of death calculations.
- Prepare for the major quiz: medical legal aspects of identification and death, and review related physical injury and sexual crime topics.