Postmortem Abiotic Phenomena: A Comprehensive Analysis
Abiotic Postmortem Phenomena
Abiotic postmortem phenomena exhibit generalized or localized expressions, providing crucial insights into the timing of death. These phenomena behave as inert entities, dependent on environmental conditions. Key characteristics include:
- Strong individual character
- Standardized data, applicable universally
- Unaffected by biochemical or enzymatic processes
- Slow and consistent progression
1. Cadaveric Dehydration
Dehydration has limited practical application in determining the time of death. However, localized phenomena, such as corneal turbidity, can be studied. Corneal turbidity depends on whether the eyes remained open or closed after death. Transparency of the choroid decreases rapidly due to scleral thinning.
2. Livideces (Livor Mortis)
Livideces can manifest as widespread or localized discolorations. Widespread livideces are particularly relevant for estimating the time of death, progressing through distinct phases:
- Initiation: 0-1 hours, speckling appears on the posterior neck.
- Translation: 1-5 hours, abundant livideces in dependent areas. Blanching occurs with pressure and position changes.
- Scale: 5-8 hours, blanching with pressure disappears slowly. No change of position causes pallor.
- 8-14 hours: Pallor upon pressure without complete disappearance, extravasation into the dermis.
- After 14 hours: No pallor with pressure, no new spots appear in different dependent positions.
- After 24 hours: No pallor to pressure.
Localized livideces are most evident in the fundus, undergoing a series of changes.
3. Cadaveric Cooling (Algor Mortis)
The body tends to equilibrate with the ambient temperature. Cooling is a valuable indicator for estimating the time of death. The cooling curve follows Newton’s Law and Ohm’s Law regarding energy transfer.
The cooling curve comprises three phases:
- Initial plateau: Rectal temperature decreases very slowly.
- Rapid heat loss: Caused by the temperature gradient between the body’s interior and the environment.
- Simple exponential phase: Continues until thermal equilibrium is reached.
Clothing slows down the cooling process, while immersion in water accelerates it.
4. Equimosis: True and False Bruising
Equimosis is characterized by the typical discoloration resulting from blood spillage due to blunt trauma.
1. Equimosis in the Living Subject
Two potential sources of error exist in diagnosing bruising: the absence of a concussion and the appearance of bruising without a contusion.
Ecchymosis without bruising can be attributed to:
- Highly elastic blood vessels that withstand trauma without tearing.
- Rapid death following heart rupture, preventing blood from reaching the periphery after trauma.
- Blunt instruments wrapped in soft materials (e.g., boxing gloves).
Ecchymosis without bruises may also result from diseases causing spontaneous bleeding, such as ecchymosis diathesis, scurvy, erythema nodosum, phosphorus poisoning, acute meningitis, and convulsive processes.
2. Equimosis in the Deceased Body
Spontaneous ecchymosis lacks a traumatic origin and can be categorized as:
- Ecchymosis due to asphyxiation: Difficult to distinguish due to small specks distributed in specific areas, such as subconjunctival ecchymoses on the face.
- Pathological ecchymosis: Occurs in certain diseases, characterized by small size and widespread distribution.