Forensic Medicine - Thermal Injuries and Electrocution
1. Electrical Burns and Electrocution - Viva Summary
1. Definition of Electrical Burn:
- Known as Joule burn or endogenous burn.
- Caused by electric current passing through body tissues.
- Different from thermal burns caused by external heat.
2. Characteristics of Electrical Burns:
- Appearance: Dry, charred, and insensitive.
- Site of Entry: Lacks typical inflammation or red line of demarcation.
- Appears as a grayish ulcer-like opening with everted, corrugated margins.
- Resembles the shape of the object causing electrocution.
- Skin ridges flattened, fingerprint pattern lost.
- Microscopic Findings: Compression of stratum corneum, honeycomb appearance of
spaces.
- Metallisation Deposits: Small metallic deposits (current pearls) at entry wounds.
3. Exit Wounds:
- Splitting of tissues (lacerated wounds).
- If at feet, shoes may be torn.
- Smaller lesions at flexures of limbs if the current jumps instead of passing through.
- Gangrene of limbs possible due to arterial spasm and thrombosis.
4. Sequelae (After-effects):
- Immediate Effects: Restlessness, irritability, excitement.
- Cardiac Complications: Angina pectoris, myocardial necrosis.
- Late Effects: Thrombosis, gangrene, necrosis, CNS disturbances, delayed cell degeneration.
5. High Voltage Current Injuries:
- Increased severity: Higher flow of current → severe burns.
- May mimic bullet, stab, or cut wounds.
- Current Pearls: Small molten metal balls embedded in tissues.
- Systemic Effects: Coagulation of blood, vessel blockage, renal failure, gangrene, shock.
- Mental Changes: Possible if current passes through the brain.
6. Hidden Sources of Electrocution:
- Overhead powerlines touching metal fences.
- Powerlines fallen into puddles of water.
- Accidental exposure during vehicle exits after electrocution.
7. Cause of Death in Electrocution:
- Instant Shock: Due to vagal inhibition (sudden cardiac arrest).
- Autopsy Findings: Burn Marks, Internal Findings (thrombosis, tissue damage,
metallisation), Systemic Damage (cardiac necrosis, CNS damage).
2. Thermal Injuries - Forensic Overview
1. Classification of Thermal Injuries Based on Causative Factor:
- Dry Burns: Flame, hot solid objects, radiant heat.
- Wet Burns: Hot liquids (e.g., boiling water, steam).
- Chemical Burns: Strong acids, alkalis, or corrosive chemicals.
- Electrical Burns: Electric current.
- Radiation Burns: Exposure to radiation (e.g., UV rays, X-rays).
2. Factors Modifying the Effect of Thermal Injuries:
- Temperature and Duration of Exposure.
- Extent of Body Surface Involved.
- Age and Health of the Victim.
- Immediate Medical Attention.
- Inhalation Injury.
3. Medico-Legal Importance of Death Due to Burns:
- Determining Cause of Death.
- Manner of Injury: Suicidal, Homicidal, or Accidental.
- Time of Death: Ante-mortem or post-mortem burns.
- Insurance and Compensation.
4. Ante-Mortem vs Post-Mortem Burns:
- Ante-Mortem Burns: Inflammatory reaction, vital reactions, soot in airways.
- Post-Mortem Burns: No inflammatory reaction, no soot in airways, absence of life
response.
5. Differentiation Between Wet, Dry, and Chemical Burns:
- Wet Burns: Moist appearance, blisters with clear fluid.
- Dry Burns: Charred and leathery skin, distinct burn lines.
- Chemical Burns: Irregular margins, discoloration, tissue necrosis.
6. Suicidal, Homicidal, and Accidental Burns:
- Suicidal Burns: Self-inflicted, extensive burns on accessible areas.
- Homicidal Burns: Signs of restraint or struggle, inconsistent patterns.
- Accidental Burns: Irregular burn patterns, clear evidence of accidental exposure.
