Electrocution

✅ What is Electrocution?

Electrocution refers to injury or death caused by electricity passing through the body.

• For injury or death to happen, the body must complete an electrical circuit (i.e., current must enter and exit).
  
  

• Common in domestic, industrial, and bathroom settings.
  
  

• Can be accidental, suicidal, homicidal, or judicial (e.g., electric chair).
  
  

⚙️ PHYSICAL FACTORS THAT DETERMINE SEVERITY

The extent of damage depends on:

1. Current (Amperage) — The amount of electricity flowing.
   
   

   • Most important factor in causing harm.
     
     

2. Voltage — The pressure that pushes current.
   
   

   • High voltage can break skin resistance.
     
     

3. Resistance (Ohms) — The body’s opposition to current.
   
   

   • Dry skin has high resistance.
     
     

   • Wet skin has low resistance (more dangerous).
     
     

4. Duration of Contact — Longer exposure = more injury.
   
   

5. Current Pathway — Determines which organs are affected.
   
   

   • Through heart or brain = high risk of death.
     
     

🧠 Path of Electrical Current in the Body

1. Entry Point: Usually the hand.
   
   

2. Internal Path: May cross chest, brain, or spine.
   
   

3. Exit Point: Usually opposite limb or the feet.
   
   

The “hand-to-foot” path crosses the heart and is the most lethal.

🧬 BIOLOGICAL EFFECTS OF ELECTROCUTION

1. Cardiac Effects

• Ventricular fibrillation: Chaotic heart rhythm → death.
  
  

• Can occur with only 50–80 mA (milliamperes) of AC (alternating current).
  
  

2. Neurological Effects

• Seizures,
  
  

• Loss of consciousness,
  
  

• Brainstem paralysis → stops heart and breathing.
  
  

3. Respiratory Effects

• Paralysis of diaphragm and chest muscles.
  
  

• Respiratory arrest can lead to secondary cardiac arrest.
  
  

4. Muscle Damage

• Severe spasms → rhabdomyolysis (muscle breakdown).
  
  

• Breakdown products can damage kidneys (renal failure).
  
  

5. Thermal Injury

• Joule heating (conversion of electrical energy into heat) causes:
  
  

  • External burns,
    
    

  • Internal tissue coagulation.
    
    

🔬 FORENSIC SIGNS OF ELECTROCUTION

1. Joule Burn / Electrical Mark

• Characteristic skin lesion at contact site.
  
  

• May look:
  
  

  • Pale,
    
    

  • Dry and sunken,
    
    

  • Central crater,
    
    

  • Raised edge.
    
    

2. Metallization

• Microscopic metal deposits from conductor embedded in the skin.
  
  

3. Streaming of Nuclei

• Under microscope: skin cells show elongation in direction of current.
  
  

4. Absence of Skin Marks

• In some cases (e.g., wet skin, bath), no external sign is seen, yet death is due to electrocution.
  
  

💉 ELECTRICAL PATHWAYS AND RISK OF DEATH

🚨 PHYSIOLOGICAL EFFECTS TO LOOK FOR

🫀 Cardiac Dysrhythmia

• Irregular heartbeat, especially ventricular fibrillation → sudden death.
  
  

🫁 Respiratory Paralysis

• Spasm of chest and diaphragm muscles → no breathing.
  
  

🧠 Brainstem Paralysis

• Seen in head-to-foot current.
  
  

• Immediate arrest of breathing and heart.
  
  

✋ “Hold-on” Effect

• Tetanic (spasmodic) muscle contraction locks victim’s grip.
  
  

• Prolongs exposure.
  
  

• Occurs more with AC than DC.
  
  

🔌 AC vs DC — Which is More Dangerous?

⚠️ IMPORTANT ELECTRICAL THRESHOLDS

💡 SKIN RESISTANCE AND MOISTURE

🔬 HISTOLOGY & MICROSCOPY FINDINGS

In skin:

• Blisters,
  
  

• Nuclear streaming,
  
  

• Vacuoles (tiny pockets of gas),
  
  

• Metallization: Metal particle deposits from conductor.
  
  

In heart:

• Contraction bands in muscle fibers,
  
  

• Wavy myocardial fibers.
  
  

In brain:

• Tiny hemorrhages (bleeds),
  
  

• White matter tearing.
  
  

🔎 TYPES OF ELECTRICAL BURNS

1. Contact Burns

• At entry or exit site.
  
  

• Small, round, deep.
  
  

2. Arc Burns

• From electricity jumping across air.
  
  

• May occur without touching the wire.
  
  

3. Flash Burns

• Superficial.
  
  

• Caused by heat from arc, not current passing through.
  
  

⚠️ CLASSIC ELECTRICAL BURN FEATURES

🛁 BATHROOM ELECTROCUTION — HIGH RISK

Why it’s dangerous:

• Water lowers skin resistance,
  
  

• Wet skin = high conductivity,
  
  

• Metal taps/fixtures act as grounding,
  
  

• Victim usually unclothed = no insulation.
  
  

☠️ DEATH FROM ELECTROCUTION: TYPES

🕵️‍♂️ FORENSIC INVESTIGATION

1. Scene Examination

• Check for:
  
  

  • Electrical appliances,
    
    

  • Wiring,
    
    

  • Signs of water or grounding,
    
    

  • Suicide notes or tampering.
    
    

2. Autopsy

• External:
  
  

  • Electrical marks (especially hands/feet),
    
    

  • Metallization,
    
    

  • Burns.
    
    

• Internal:
  
  

  • Look for myocardial damage, respiratory muscle injuries.
    
    

3. Histology

• Skin: streaming, metallization.
  
  

• Heart: contraction bands.
  
  

4. Microscopy

• Use scanning electron microscope (SEM) to detect:
  
  

  • Metal particles, trace conductors.
    
    

⚰️ HOMICIDE, SUICIDE, OR ACCIDENT?