Electrical, Thermal, Regional and Traffic Injuries

Electrical injury follows a small handful of physical variables: current pathway through the body, voltage, current type (alternating vs direct), duration of contact, and tissue resistance at the contact points. AC is more dangerous than DC at low voltages because it produces sustained muscle tetany; the victim's grip closes around the conductor and the contact duration extends. The autopsy translates these variables into recognisable skin and internal findings.

• Current pathway determines which organs are damaged. Hand-to-hand current crosses the chest and is the canonical cardiac fibrillation route. Hand-to-foot current crosses the abdomen and viscera.
• Voltage brackets the case into low (under 1000 V) and high (1000 V and above). Indian household supply is 230 V single-phase and 400 V three-phase; transmission and traction lines run 11 kV, 33 kV and higher.
• Resistance at the skin determines how much current actually flows. Wet skin, sweaty hands, salt-water immersion drop resistance to under 1000 ohms; dry, calloused skin can exceed 100,000 ohms.

Electric mark (Joule burn). The signature finding of low-voltage electrocution. A pale, crater-like cutaneous lesion with a slightly raised, firm, sometimes blistered margin. Typically a few millimetres across, dry, sharply demarcated, and almost always overlooked unless the examiner is specifically searching the hands. Histology shows nuclear streaming, vacuolation of the epidermis and metallisation (if the conductor was copper or aluminium). The Joule mark is preserved by excising a wide ellipse around it and fixing in formalin for the FSL or institutional pathology lab.

Low-voltage electrocution. The Indian domestic caseload: a wet bathroom geyser, a frayed wire on a desert cooler in summer, a careless mains repair. External findings are minimal; the Joule mark on the fingertip or palm can be the only visible clue. Cause of death is ventricular fibrillation. The autopsy must specifically search both hands, both feet (for the earth contact), and any clothing for melted fibres or singed margins around contact points.

High-voltage electrocution. Power-line and substation accidents, traction-line contact (railway, metro). External findings are severe: entry and exit burns, deep muscle necrosis, charring along the current path, sometimes flash burns where an arc jumped to the body. The internal injuries can be lethal independently of the cardiac effect.

Lightning. Distinctive enough to merit its own discussion. The Lichtenberg figure is a transient, branching, fern-like reddish pattern on the skin caused by capillary damage from the discharge; it fades over hours. Metallic objects on the victim (coins, keys, jewellery) may be magnetised. Clothing is frequently torn or "exploded" off the body by the steam flash. Cause of death is usually cardio-respiratory arrest.

Thermal injuries split into flame, scald, contact, chemical and radiation. Each leaves a different external pattern, and each carries a different forensic argument about who, when and how. The single most important finding across the family is whether the victim was alive when the burning happened.

• Flame burns show singed hair, soot deposition on exposed skin, and a depth gradient from first to fourth degree depending on contact duration and temperature.
• Scalds (hot liquid or steam) characteristically lack singed hair, because the temperature is below the threshold for hair charring. Splash pattern (irregular margins) suggests an accident; immersion pattern (sharp horizontal margin, "stocking-and-glove" distribution) suggests deliberate immersion, classic in child abuse.
• Contact burns match the shape of the contact object. A clothes iron, a kitchen tava, a heated metal bar each leaves its own outline.
• Chemical burns divide into acid (coagulation necrosis, eschar firm and dry) and alkali (liquefactive necrosis, eschar soapy and slippery). Eschar colour helps identify the agent: sulphuric brown to black; nitric yellow to brown; alkali pale and soapy.
• Radiation burns develop slowly, often painlessly at first, and present hours to days after the exposure event.

Vital signs of burn. The findings that say the victim was alive when burning happened. Critical because staged burns of an already-dead body are a classical dowry-death cover-up.

Dowry-death pattern. The Indian medico-legal context that sits behind this whole section. Section 80 of the Bharatiya Nyaya Sanhita 2023 (the BNS provision replacing Section 304B of the IPC) makes dowry death a distinct offence: Section 80(1) defines the offence as a woman's death by burns or bodily injury under abnormal circumstances within seven years of marriage, with evidence of dowry-related cruelty, and Section 80(2) provides the punishment of not less than seven years' imprisonment. The classical staged scenario is a kitchen kerosene stove "bursting" while the woman was cooking. Forensic markers that argue against accident and toward homicide include:

• Burn distribution incompatible with a stove burst. A stove burst flame travels upward; burns to the back, buttocks and posterior thigh are inconsistent.
• Kerosene odour or distribution on clothing that suggests deliberate pouring. Clothing examination at the FSL chemistry section confirms accelerant pattern.
• No singed eyebrows or eyelashes despite face burns. Suggests the face was burned post-mortem, with no reflex closure.
• Absent vital signs of burn. Soot-free airway and CO-Hb under 10% indicate the burning happened after death.

This pattern overlaps with the broader work on accelerant patterns covered in Fire and Burn Pattern Interpretation and with the autopsy protocol set out in Autopsy and Post-Mortem Examination.

1. External examination
   Map burn distribution on a body chart; note depth, hair sparing, margins, eschar colour and any contact pattern.
2. Search the airway
   Open trachea and bronchi; look for soot deposition on the mucosa. Sample for histology.
3. Collect heart blood
   Sample for carboxy-haemoglobin assay; >10% saturation indicates breathing during the fire.
4. Sample clothing for accelerants
   Multiple sites of clothing, sealed in metal tins (not plastic), forwarded to FSL chemistry.
5. Histology of burn margins
   Wide ellipses around representative burn margins, fixed in formalin, examined for ante-mortem inflammatory response.

A blunt-force or blast injury delivers different patterns at different anatomical regions. The forensic examiner is trained to read each region's signature.

Head injuries. Read at four levels: scalp, skull, meninges and brain. Scalp injuries are easy to underestimate because hair hides them; the examination requires shaving and palpation. Skull fractures classify into:

• Linear: single hairline crack, usually from low-energy blunt force.
• Depressed: fragment driven inward, characteristic of focal high-energy impact (hammer, stone).
• Comminuted: multiple fragments, high-energy or repeated impact.
• Ring fracture (around foramen magnum): falls from height with vertical impaction.

Intracranial bleeds split by anatomical layer: extradural haematoma (EDH, between dura and skull, classically from middle meningeal artery rupture); subdural haematoma (SDH, between dura and arachnoid, from bridging vein tear); subarachnoid haemorrhage (SAH, in the cerebrospinal fluid space, often from vertebral artery rupture in basal injury). Brain contusion (cortical bruising) and counter-coup injury (contusion on the side opposite the impact) are the soft-tissue parenchymal findings.

Chest injuries. Rib fractures, in their pattern, tell you which mechanism. A single rib fracture in isolation suggests focal trauma. A segmental pattern (each rib fractured in two places along a line) produces a flail chest with paradoxical motion (the segment moves inward on inspiration). Crushing injuries produce bilateral, multi-level fractures. Pulmonary contusion (lung bruising) underlies overlying chest wall injury. Tension pneumothorax (air leaking into the pleural space without escape) and cardiac tamponade (blood accumulating in the pericardial sac) are the two acute lethal complications.

Abdominal injuries. Solid organ injuries (liver, spleen, kidney) produce free intraperitoneal haemorrhage. Hollow viscus injuries (small bowel, large bowel) produce peritoneal soiling and slower-onset peritonitis. The two categories together cover most blunt abdominal trauma. Retroperitoneal haematoma (in the space behind the peritoneum) carries large volumes silently and is missed unless specifically dissected.

Indian roads run on a high baseline of pedestrian and two-wheeler fatalities. NCRB data through the 2020s consistently place two-wheeler riders and pedestrians together at well above half of all road traffic deaths. The injury patterns permit an experienced examiner to reconstruct the crash sequence from the autopsy findings alone.

Pedestrian impact runs through three phases, each leaving its own marks.

1. Primary impact (bumper to leg)
   Transverse bruise or fracture of tibia/fibula at bumper height. Bumper height indicates vehicle type: car (~40-50 cm), SUV (~55-65 cm), truck (>70 cm). Side of the bumper mark indicates direction of approach.
2. Secondary impact (body to bonnet)
   Pedestrian thrown onto the bonnet; head and chest strike the windscreen and A-pillar. Produces facial injuries, head injuries, and chest contusions.
3. Tertiary impact (body to ground)
   Pedestrian thrown clear and strikes the road. Produces gravel rash, palmar and knee abrasions, and additional head injury from the second impact.

Passenger injuries.

• Whiplash injury. Sudden hyperextension-flexion of the cervical spine in rear-end collisions. Soft-tissue injuries to ligaments and muscles of the neck; visible at autopsy only if severe.
• Marshall's triad. The classical injury complex from the steering wheel in unrestrained drivers: rib fractures (anterior chest wall), sternal fracture (transverse), and ruptured thoracic viscus (commonly the aorta at the isthmus, but heart and pulmonary vessels are also involved). Three findings together are diagnostic of steering-wheel impact and therefore of unrestrained driver.
• Seatbelt sign. A linear bruise running diagonally across the shoulder and abdomen, marking the seatbelt's path. Indicates a restrained occupant. The presence of the seatbelt sign with absence of Marshall's triad places the occupant in the restrained category and shifts injury distribution toward seatbelt-associated abdominal injuries (mesenteric tear, lumbar Chance fracture).

Two-wheeler rider injuries. The dominant Indian crash category.

• Head injury dominates outcomes. The helmet protects the cranium and reduces severity of skull fractures and intracranial bleeds; the helmet's protective effect is one of the most consistent findings in Indian trauma data.
• Gravel rash (extensive abrasions from skin-to-road contact) is universal in unprotected riders.
• Lower-limb fracture patterns include tibial shaft fracture from impact and ankle injury from foot trapping under the bike.

Hit-and-run reconstruction. Trace evidence at the scene and on the body tells the FSL trace-evidence section what to look for on a suspect vehicle.

• Paint smear on clothing or skin. Matched against a paint database for vehicle make and model.
• Glass fragments embedded in clothing or wounds. Refractive index and elemental analysis match to a suspect vehicle's headlight or windscreen.
• Fibre transfer onto the vehicle. Carpet fibre from the suspect vehicle on the victim's clothing, or vice versa.

The trace-evidence work ties this topic to Accident Investigation and Hit-and-Run, where the reconstruction protocol is set out in detail.

Sharp-force injuries cluster the same way firearm injuries do: suicidal, homicidal, accidental. Reading the manner of death from the body and the scene together is one of the post-mortem examiner's specific skills.

Hesitation marks. Parallel, superficial, often non-fatal cuts running adjacent to a deeper, fatal main wound. They represent the suicidal subject's tentative initial attempts before committing to the final cut. Characteristic features:

• Parallel orientation to the main wound.
• Superficial depth, usually only through epidermis and superficial dermis, not bleeding heavily.
• Site anatomically reachable by the dominant hand: wrist (palmar aspect of the non-dominant wrist for a right-handed person), front of neck, chest over the heart.
• Often more numerous than expected, sometimes 4 to 12 small cuts beside the main wound.

A wound without hesitation marks is not necessarily homicidal, but the presence of hesitation marks is a strong indicator of self-infliction.

Site and surrounding context. Suicide cases show a small, consistent vocabulary of sites: wrists (cuts), front of neck (throat-cutting), chest (over the heart), and for firearms the right temple, hard palate, chin and mid-chest. Wounds at sites anatomically unreachable by the dominant hand argue against self-infliction. Surrounding context (locked room from inside, suicide note, prior psychiatric history, weapon in or near the deceased's hand) builds the manner-of-death case but does not by itself prove it. Staged scenes are the standard concern.

Common Indian case categories. Three crop up at exam volume and on real autopsy benches:

• Dowry burn. The kitchen-stove-burst account against the body findings; tested by airway soot, CO-Hb, and accelerant pattern on clothing.
• Traffic fatality investigation. Distinguishing primary cause of death (head injury at impact) from secondary cause (haemorrhage from limb injuries); informs criminal liability versus medical negligence questions.
• Custodial death. The autopsy board, the videography requirement, and the magistrate's role in producing a report the High Court can rely on.