Overview
Trauma is bodily harm with or without structural alterations, resulting from interaction with physiochemical agents that impart energy to tissues. They may cause apparent damage (wound) or produce physiological imbalance (e.g. cardiac arrest by neural stimulation) and secondary effects (e.g. thrombosis, infection, obstruction of tubular organs)
An injury is any harm caused to any person in body (physical), mind (psychological), reputation or property
Clinically, a wound is any injury where there is a breach of the natural continuity of skin or mucous membrane
In medico-legal practice, wound and injury are synonymous. But strictly wound includes any lesion, external or internal, caused by violence, with or without breach of continuity of skin.
- Wounds based on severity of injury (legally)
- Simple
- Grievous
- Wounds based on nature of injuries (medico-legally)
- Suicidal
- Homicidal
- Accidental
- Defense wounds
- Fabricated or self-inflicted wounds
- Based on time of infliction
- Post-mortem
- Ante-mortem
- Types of trauma
- Blunt force trauma
- Sharp force trauma
- Firearm injury
- Thermal injury
- Electrical injury
- Atmospheric pressure
- Radiation injury
- Chemical reaction
Blunt Force Trauma
Blunt force trauma occurs when a moving object strikes a body (e.g. blow) or a moving body strikes a fixed body (e.g. fall). The contact results in the transfer of kinetic energy.
Classification of blunt force trauma
| Classification | Description |
|---|---|
| Abrasion | Injury to the skin with removal of the epidermis by friction against a rough surface, or destruction of the epidermis by pressure. Abrasions may contain trace evidence. The site of abrasion may also indicate the nature of the crime e.g. homicide for abrasions around the neck (throttling) or around the nose and mouth (smothering) |
| Contusion (bruise) | Leakage of blood from ruptured small vessels into the surrounding skin caused impact with a blunt object without destruction of skin. Post-mortem lividity in the early days can mimic a bruise |
| Laceration | Tears or splits of skin, mucous membranes, muscles, or internal organs produced by application of blunt force which stretches tissue beyond their limits of elasticity. Lacerations caused by tangential force may give one clean-cut edge with the other edge being ragged and undercut (flap-like) |
Types of abrasion
| Abrasion | Description |
|---|---|
| Tangential abrasion (linear abrasion or scratch) | In the form of a linear mark caused by a narrow, sharp object (fingernails) |
| Brush abrasion (graze) | In the form of a wider mark caused by a broad, rough surface |
| Impact abrasion | A form of compression abrasion that takes the form of the impacting object (”stamp”) caused by vertical impact |
| Contact abrasion | A form of compression abrasion that takes the form of the impacting object caused by sustained pressure e.g. ligature mark |
| Patterned abrasion | The abrasion takes the form of the impacting object |
| Non-patterned abrasion | The abrasion does not take the form of the impacting object |
Types of bruises
| Bruise | Description |
|---|---|
| Ectopic bruise | Formed when blood percolates along the lines of least resistance to a site remote to the application of force e.g. peri-orbital hematoma (raccoon eyes) |
| Patterned bruise | A bruise that reflects the pattern of the impacting object. Caused by hard patterned objects with ridges and grooves. |
| Come-out bruise | A deeply situated contusion that manifests externally after several hours or days. |
| Tramline bruise | Parallel, linear contusions caused by impact with rod-shaped weapons |
- Factors that determine the severity, extent, and appearance of blunt injuries
- Amount of force delivered to the body
- Time over which the force is applied
- Region struck
- The extent of the body surface over which the force is delivered
- The nature of the weapon
- Abrasion
- Superficial injury to the skin in which the outer layer is scraped off
- Examples: scratch from a fingernail, grazing of skin from dragging a body over a rough surface
- Examination of abrasions allows inferences to be made about the nature and shape of the object, time of the injury (recent or healed), Type of the assault, and the cause of the mechanism of death
- Bruises (contusion)
- Blunt force injury that occurs when blood vessels in the skin or internal organ are ruptured
- Resulting bleeding may be small (petechiae) or large (hematoma)
- Examination of bruises allows inferences to be made about nature and shape of the object, time of the injury (colour changes reflect the age ofthebruise), Type of the assault and the cause of the mechanism of death
- Extent to which someone bruises depends on:
- Age- older people bruise more easily
- Gender- women bruise more easily than men
- Presence of an underlying disease e.g bleeding disorder, liver disease
- Postmortem pooling of blood I’m the dependent arts of the body (lividity or hypostasis) should not be mistaken for bruises
- Lacerations (tear)
- A wound with irregular edges caused by the application of blunt force which causes tearing or splitting of the skin
- Examination of lacerations allows inferences to be made about nature and shape of the object, time of the injury (recent or healed), the Type of the assault and the cause of the mechanism of death
- Characteristics of a laceration
- Ragged edges, bulging fat, crushed hair bulbs
- Associated bruising and abrasion of skin edges and adjacent tissue
- Tissue bridges in depth of wound (intact nerves, vessels, and tendons)
- Hemorrhage is less (except scalp trauma)
- Foreign bodies may be found in the laceration
Postmortem lividity vs bruise
| Bruise (contusion) | Postmortem lividity | |
|---|---|---|
| Cause | Rupture of vessels and extravasation of blood | Engorgement of vessels due to pooling of blood |
| Site | Anywhere in the body | Dependent parts of the body |
| Surface | Elevated | No elevation |
| Colour | Colour evolves over time from red, bluish-black to brown (hemosiderin), greenish (haematoidin), to yellow (bilirubin) | Normally purple |
| Incision | Cannot be washed off | Can be washed off |
| Histology | Inflammation | No inflammation |
Sharp Force Trauma
These wounds are caused by pointed and sharp-edged weapons. Injury is caused by the separation of the skin and soft tissue. The examination allows inferences to be made about the nature and shape of the object, the time of the injury (recent or healed), and whether the victim tried to defend themselves (presence of wounds on the forearm or hands to deflect stabbing)
Classification of Sharp Force Trauma
| Classification | Description |
|---|---|
| Stab wound (incised-stab) | Caused by thrusting (or falling onto) a sharp-pointed instrument e.g. a knife |
| Puncture wound (lacerated-stab) | Caused by thrusting (or falling onto) blunt-pointed instruments e.g. screwdriver |
| Penetrating injury | The instrument terminates into tissue, organ, or cavity |
| Perforating | The instrument transfixes the body with an entry and exit wound |
- Factors that determine the severity, extent, and appearance of blunt injuries
- The nature of the blade
- The direction of the thrust
- The movement of the blade in the wound
- The movement of the victim
- Characteristics of a stab wound
- Clean-cut, well-defined margins
- More bleeding
- Lack of associated bruises and abrasions
- Lacks tissue bridges
Differences between an incision and laceration
| Characterstics | Incision | Laceration |
|---|---|---|
| Edges | Sharply outlined edges, may be straight, curved or angled depending on how the blade was used on or in the body | Irregular and ragged edges. Straight, round, oval, star- shaped. |
| Surrounding tissue | Absence of bruise or abrasion on edge of the wound | May have associated abrasions and bruises on surrounding tissue |
| Loss of hair | No loss of hair around wound | Hair around the wound may be absent |
| Tissue bridges | No bridging strands of tissues across the wound | Tissue bridges (usually more elastic structures resistant to tearing and stretching) e.g. nerves may be present |
| Foreign material | Usually no foreign material around or in the wound | Foreign material (debris) often present if injury caused by dirty instruments or surfaces |
| Bleeding | Bleeds profusely | Bleeding less than in sharp wounds |
Complications associated with injury
- Local
- Hemorrhage
- Infection
- Systemic
- Shock
- Bleeding disorders
- Various types of embolisms
Determination of factors that may influence survival after injury
- Individual factors
- Person’s mental state
- Presence or absence of pre-existing disease
- Fitness of the person
- Nutritional factors
- Factors related to the injury
- Type, site and severity
- Can assist a court to determine the probable time between injury and death and whether the victim could have been capable of any activity after the injury
Checklist for documenting and interpreting injuries
- Treat all patients with empathy and without bias
- Obtain informed consent (e.g. using a hospital consent form). If the patient is brought in by a police officer, note the officer’s details as well as the police case number (OB number) and the referring police station
- Obtain a good history of the incident and past medical history of the patient
- Begin with a general examination and then proceed to examine the injured area/ s
- Ensure the right environment with good light for examination
- Consider each wound individually
- Use a ruler to measure size of the wound
- Record your findings using the P3 form supplemented by diagrams where indicated, noting the time and place of examination
- Separate findings of fact from opinions in your notes
- Consider mode of injury and/ or cause of death
- Use body charts/ diagrams to show and locate injury
- Use fixed anatomical landmarks (e.g. heel of foot and not nipple) to fix location of injury
- If possible, take photographs with a scale and identity label
- Examine hidden areas
- Palms and soles
- Armpits and inner aspects of the arms
- Inner thighs and genital areas
- Insides of mouth, lips and throat
- Eyelids, scalp and back
- If no injuries are apparent on initial examination, re-examine in 24 hours
- Look for and note complications of injury (e.g. infection)
- Look for changes of ageing of the wound
- Exclude injuries caused by medical treatment (e.g. bruising on the chest caused during resuscitation)
- Take appropriate specimens for special investigations
Ensure proper chain of custody by signing the exhibit memo form when handing over the specimen to the investigating officer.
