General pathology · Environmental pathology
Mechanical and electrical injury: abrasion, contusion, laceration, wounds !
- Lesion
Blunt and sharp forces leave typical wounds on the body; electric current burns deep along its path and can stop the heart.
Updated 2026-11-01
What it is
Recognising the type of wound tells how it was made, which matters for treatment and for forensic medicine. Blunt force produces abrasions, contusions and lacerations; sharp objects produce incised and stab wounds; firearms produce entry and exit wounds. Electric current causes damage that is often much larger inside than on the skin. In Colombia, violence and road traffic injuries are major causes of death in young adults.
Key facts
- The colour of a bruise follows haemoglobin breakdown: bilirubin (green-yellow) and haemosiderin (brown).
- Patterned bruises, injuries of different ages and injuries that do not fit the story raise concern for abuse.
- Lightning can leave fern-shaped skin marks (Lichtenberg figures) that fade in hours.
- Late effects of electrical injury include cataracts and neurological deficits.
Step by step
- Electric current enters the body at the contact point and seeks the path of least resistance.
- Nerves, blood vessels and muscle conduct well; dry skin resists and burns at entry and exit.
- Heat along the path cooks deep muscle while the skin may look minor.
- Dead muscle swells (compartment syndrome) and releases myoglobin (rhabdomyolysis and kidney injury).
- Current crossing the heart causes arrhythmia: alternating current tends to ventricular fibrillation, lightning to asystole.
The wounds to recognise
| Wound | Cause | What it looks like |
|---|---|---|
| Abrasion | Scraping or friction against a rough surface | Loss of the surface epidermis; direction of the scrape may show |
| Contusion (bruise) | Blunt force that breaks small vessels under intact skin | Bleeding in the tissue; colour changes from red-blue to green to yellow-brown |
| Laceration | Blunt force that tears tissue | Irregular edges, bruised margins, bridges of nerves and vessels in the depth |
| Incised wound | Sharp edge drawn across the skin | Clean straight edges; longer than it is deep |
| Stab wound | Sharp, pointed object pushed in | Deeper than it is long; can injure deep organs |
| Gunshot wound | Projectile | Small entry with an abrasion ring; soot or stippling at close range; exit usually larger and irregular |
Test yourself
Think of the answer, then tap the question to see it.
How is a laceration told apart from an incised wound?
A laceration (blunt force) has irregular, bruised edges with tissue bridges; an incised wound (sharp edge) has clean edges and no bridges.
Why can a patient with a small electrical skin burn have life-threatening injuries?
The current heats deep muscle and vessels along its path, causing hidden necrosis, compartment syndrome, rhabdomyolysis and arrhythmia.
What does soot or stippling around a gunshot entry wound indicate?
That the weapon was fired at close range.
Why does a bruise change colour over the days?
Haemoglobin in the tissue is broken down to biliverdin and bilirubin (green-yellow) and then to haemosiderin (brown).
Related
- Hemorrhage: petechiae, purpura, ecchymosis, hematoma, and what blood loss does
- Healing of skin wounds: first and second intention
- Thermal injury: burns, hyperthermia and hypothermia
- The autopsy: clinical and medicolegal
Related conditions
- Penetrating trauma (stab and gunshot wounds)
- Burns (thermal, chemical, electrical; inhalation injury)
- Electrical and lightning injury
- Blunt abdominal trauma
- Major trauma (polytrauma): ATLS primary survey
- Acute compartment syndrome
- Rhabdomyolysis
- Subdural haematoma
- Epidural haematoma
- Child maltreatment (physical abuse, abusive head trauma, neglect)
- Intimate partner and sexual violence (mental-health care)
- Cardiac arrest (VF, pulseless VT, asystole, PEA)
Elsewhere in DurgiPedia
- Skin: epidermis layers, dermis, hypodermis
- Wound healing: phases and scar
- The ventricular action potential
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Cuts and puncture wounds: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); Electrical injury: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026).
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Representative model, for educational purposes only.