Wound Classification and Types

Wound Classification and Types

• Wounds are circumscribed injuries from external forces, encompassing surgical, traumatic, and accidental injuries. Injury is a synonym.
• Injury can be caused by mechanical (e.g., blunt force), or non-kinetic forces (e.g., thermal, chemical, electrical).
• Skin acts as an initial barrier against the environment and pathogens. Damage leads to potential scar tissue formation.
• Injuries can be classified as kinetic (blunt and sharp force) or non-kinetic (thermal, chemical, electrical, radiation).
• Severity classification encompasses simple and grievous injuries. Timing of injury: antemortem, perimortem, or postmortem. Also, manner can classify them.
• Maltese law differs, describing bodily harm as either grievous or slight (article 215 of the Criminal Code).

Blunt Force Injuries

• Contusions (Bruises): Develop from blood extravasation (subcutaneous/submucosal) following capillary rupture. Distinct color changes (e.g., red to brown, over 7-12 days). Shape can suggest the weapon. Location is important in identifying type (e.g., neck). Include ecchymoses (bruising) or effusion in tissues.
• Abrasions (Scratches/Grazes): Involve superficial skin layers, with trivial clinical effects, but important forensically. Indicate direction of force (e.g., heaped-up epithelium at end of a scratch) based on weapon's shape/movement. Patterned abrasions (e.g., rope marks, tire marks). Location is important forensically (e.g., fingernails on neck). Occur postmortem.
• Lacerations: Blunt force injuries that split skin's full thickness, potentially deeper. Can contain trace evidence & irregular margins, shapes may indicate the weapon.

Sharp Force Injuries

• Incised Wounds: Sharp force trauma. Elongated marks with depth.
• Cuts & Slash Wounds: Incisions with longer marks than depth.
• Stab Wounds: Deeper than wide wounds (penetrating skin and tissue).
• Chop Wounds: Combined sharp & blunt force, severe and deep, caused by cleavers, swords, axes.
• Defense Wounds: Often found on ulnar borders of forearms, resulting from raised arms during self-defense.

Post-Mortem Changes

• Lividity (Hypostasis): Blood pooling due to gravity and lack of circulation after death.
• Rigor Mortis: Stiffening of muscles and joints a few hours after death (1-4 days).

Gunshot Injuries

• Ballistics: Study of projectile motion and effects; caliber and shape influence tissue interaction and kinetic energy loss. High-velocity projectiles disrupt more extensively. Longer the tract, greater the deformation. Extent of injury depends on mechanical tissue damage, shearing/compression/stretching due to cavities, and secondary injuries due to bullet fragmentation.
• Types of Gunshot Wounds: Penetrating and perforating.
• Smooth-bore Weapons (e.g., shotguns): Smooth barrel, shot dispersed in cone shape, range effects severity, contact wounds show singeing and blackening/tattooing of skin due to unburnt propellant; long range has widespread pellets. Dispersion is not used to estimate range.
• Rifled Weapons (e.g., pistols, rifles): Rifled barrels, impart spin to bullet, providing accuracy & rifling marks, caliber = diameter of barrel.
• Ammunition Components: Metal/cardboard cases, primers, propellants, bullets (metal)
• Firing Mechanism: Trigger activates firing pin, striking primer and igniting gunpowder, gas pressure propels the bullet.
• Firing Range Classification:
  • Close range: Muzzle contact, particles driven into wound
  • Near-contact: No contact, soot band, no tattooing
  • Intermediate range: Powder tattooing
  • Distant range: No soot or tattooing
• Wound Appearance (Rifled): Entry: circular, ragged, or stellate; exit: larger, irregular, multiple if bone fragmentation.
• Ammunition Comparison: Comparison microscopy for identification.

Thermal Injuries

• Body Temperature Regulation: Hypothalamus controls via the autonomic nervous system, maintaining 36.8°C (range 36.4-37.3 °C). Elevated temps lead to impaired heat regulation and potential hyperthermia.
• Hyperthermia: Core temperature ≥ 40.6°C (105°F), potential heat stroke.
• Heat Exhaustion vs. Heat Stroke: Heat exhaustion (normal temp, fluid loss, sweating); Heat stroke (temp>40°C, cessation of sweating, red dry skin).
• Types of Thermal Injuries: Scalds (moist heat), burns (dry heat), cold injuries, chemical burns, electrical burns, radiation burns.
• Scalds: Hot fluids cause redness and blistering. Clothing affects depth of burns.
• Burns: Classified by depth (first degree - erythema; second degree - full epidermis damage, regenerates; third degree - full-thickness damage, heals by scarring, rule of nines for burn calculation).
• Pathologic Role in Fires: Identify identity, timing of death, cause related to fire. Causes of victim's being in fire and not escaping fire.
• Post-mortem Fire Examinations: Burning body preservation, accelerant on clothing; children are more susceptible to full-body burn destruction; Pugilistic attitude; Cherry pink colour skin, soot below vocal cords, indicates breathing and thus, live victim in fire; Hypoxia (from smoke) a major cause of death.
• Carbon Monoxide Poisoning: High CO blood saturation indicates victim alive in fire.
• Hypothermia: Body temperature low, shivering stops, internal damage.
• Frostbite: Prolonged hypothermia, localized to extremities, digit infraction.
• Explosions: Blast effects, projectile impact, burns, falling debris, injury extent depends on distance from blast.
• Electrical Injuries: Death can result from arrhythmias, respiratory paralysis, and brain stem paralysis. Current intensity, exposure time effect extent.

Explore the various classifications of wounds, including surgical, traumatic, and accidental injuries. Understand how injuries are caused by different forces and their potential severity. This quiz will cover both blunt and non-kinetic injuries, delving into legal classifications as well.