Wound Definition and Classification

Wound Definition and Classification

• A wound is a disruption in the continuity of tissues, caused by external mechanical force.
• Examples of tissues include skin and bone.

Legal Wound Classification

• Simple Wounds: Heal in less than 20 days and cause no permanent disability.
• Dangerous Wounds: Heal in more than 20 days or result in permanent disability.
• Fatal (Mortal) Wounds: Lead to death.

Medicolegal Classification of Wounds

• Abrasions (Scratches): Damage to the superficial skin layers (epidermis) or upper dermis, due to friction or pressure from a blunt object.

  • Graze: a linear abrasion from a sharp point over the surface.

• Types of Abrasions

  • Pressure abrasions: caused by pressure, like nail marks or rope marks (ligature marks) in hanging or strangulation.
  • Sliding abrasions: caused by dragging or friction, like car accidents.

• Medicolegal Importance of Abrasions: Abrasions can indicate the shape of the object used to cause them. Smothering or throttling often leads to nail abrasions in specific patterns

  • Ligature marks are shaped like the rope used.
  • Bite marks are unique; human bites typically have two curved rows.
  • Animal bites usually have two parallel rows.
  • Car accidents leave tire impressions and shapes on the victim.

• Abrasions and medicolegal significance: Fingernail abrasions are important, due to their frequency in assaults. They may be of two types: Sliding or pressure.

  • Sliding may be due to resistance as with rape or murder.
  • Pressure may be from smothering or throttling

• Age of Abrasions: Can be correlated to the crime date.

  • The first two days are usually covered with a soft scab.
  • After 3 days, it's a dry scab.
  • After a week, the scab falls, leaving a red area that heals in around three weeks.

Contusions (Bruises)

• A contusion/bruise is the extravasation of blood into tissues due to ruptured blood vessels from blunt force.
• The common location is the skin with potential for tissues deeper in the body, including internal organs, to also be contused.

Factors Modifying Bruise Appearance

• Severity of the blow: The force of the blow, not the object's size, predominantly impacts the bruise extent.
• Time of death: A blow to the pericardium can cause sudden death before noticeable bruising is apparent.
• Underlying conditions (disease): Conditions like haemophilia or liver disease can augment the appearance of bruises from smaller blows.
• Tissue type: Vascular tissues (eye lids, labia major) bruise more prominently with minor strikes. Tough tissues (palm, sole) are more resistant.
• Age: Increased susceptibility to bruising in very young and older people.
• Gravity: Bruises may shift from the initial impact area due to gravity.

Medicolegal Importance of Bruises

• Shape: Bruises can mirror the shape of the object responsible for the injury. Common examples include sticks (tramline), human bite, and animal bite patterns.
• Resistance: Bruises can point toward resistance during an assault.

Site of Bruises

• Bruises often occur at the force point, but they may shift from the original injury site due to gravity.

Age of Bruises

• The color of a bruise can assist in assessing its age.
• Fresh bruises are bright red or blue.
• Over time, the color transitions to green, brown, and yellowish.
• N.B. hemosiderin (iron-containing pigment) causes a brown tinge.
• Stages take about 2-3 days per color change with progression and resolution by 1-3 weeks

Traumatic vs. Pathological Bruising

• Some diseases increase susceptibility to bruising from minimal trauma (e.g., hemophilia, cirrhosis, etc.)

Antemortem vs. Postmortem Bruises

• Antemortem: Often show swelling, size variation, and color changes.
• Postmortem: Appear small, without swelling or significant color change

Lacerations (Contused Wounds)

• Involve torn or split tissues, caused by crushing or grinding blunt instruments (e.g., car accidents, falls).
• Characteristics: Damaged edges are often irregular and abraded.
• Tissue Bridges: Blood vessels, muscle fibers, and nerves often cross the wound, preventing significant gap formation.
• Contamination: Lacerations are typically highly susceptible to microbial contamination

Subtypes of contused wounds:

• Crushed wound: tissues are crushed or amputated (e.g., car accidents).
• Torn wound: a fragmented flap of skin is separated (machine or other).
• Rupture of internal organs: severe internal damage.
• Avulsion: skin separation.
• Split/Cut lacerations: sharp instrument against bone.

Incised (Cut) Wounds

• Caused by sharp objects drawing across the tissues.
• Characteristics: Clean, straight edges, without irregular tearing. Edge regularity can vary, depending on the causative object (e.g., broken glass might have irregular edges). Absence of bruising or abrasions. Gaps in the wound are likely; tissues retract.

Varieties of incised wounds:

• Homicidal/Hesitation Wound: Close, multiple parallel small cuts indicate hesitation.
• Defense Wound: Incisions in the palm, or forearm areas.
• Surgical incisions: intentional cuts.

Postmortem cut wounds

• Indicate no gap (no retraction of tissue).
• Tissues lack elasticity.
• No vital reaction.

Age of Incised Wounds:

• 12 hours: The edges are red and swollen.
• 36 hours: New vessels grow.
• 5 Days: New vessels obliterate.
• 10 Days: The wound heals with primary intention
• 3 weeks: The scar is red.
• 3 months: The scar is coppery-brown
• 6 months: The scar is white.

Stab Wounds

• A penetrating wound caused by forcing a sharp, pointed object into the body.

• Characteristic: Deep wound with cleanly-cut edges but are a greater risk because of the possibility of internal damage and complications.

• Object identification: The length and orientation can infer the nature of the impacting weapon, whether it has a handle or not, for penetration depth.

Fabricated/Self-Inflicted Wounds

• Simple wounds caused voluntarily by the individual.
• Often superficial, located in accessible areas (e.g., extremities).
• No correlation with the stated timeline of the wounds, typically.

Defense Wounds

• Result from the victim attempting to defend themselves.
• Typical features depend on the self-defense action (e.g., punching, kicking, striking with a blunt object or knife).

Causes of Death from Wounds

• Early:
  • Hemorrhaging: Blood loss prevents blood circulation and causes organ failure
  • Traumatic shock: Primary, caused by factors directly related to the wound (e.g., vagal inhibition), or Secondary, which is an indirect effect of the wound (e.g., histamine-like substances and vascular responses triggering potentially lethal inflammatory responses).
• Late:
  • Sepsis: Severe infection impacting multiple organ systems.
  • Surgical interference: complications from medical intervention.
  • Suprarenal hemorrhage: Bleeding into the adrenal glands.
  • Disseminated intravascular coagulation (DIC): Widespread blood clotting interfering with blood perfusion.

Other Relevant Information

• Age of wound(s) determination depends on injury type
• Color changes over time for certain injuries

This quiz covers the definitions and classifications of wounds, focusing on their legal and medicolegal aspects. It details simple, dangerous, and fatal wounds, as well as different types of abrasions. Understanding these classifications is crucial for legal and medical professionals.