Wound Classification and Types

Wound Definition

• A wound is a disruption of tissues caused by an external mechanical force.
• Injury is often used interchangeably with wound but can have a broader meaning.

Wound Types

• Wounds are classified based on the force that caused them:
  • Mechanical force (blunt or sharp)
  • Heat, cold, chemicals, electricity, or radiation

Severity Factors

• The severity of a wound depends on the force delivered and the time it was applied.

Legal Wound Classification

• Simple wounds: Heal quickly (less than 20 days), with no permanent infirmity.
• Dangerous wounds: Serious injuries, may cause permanent infirmity or take more than 20 days to heal, but are not fatal.

Permanent Infirmity

• Defined as the loss of a functioning organ or loss of function (total or partial).
• Loss of a non-functional eye is considered disfigurement, not permanent infirmity.

Abrasions (Scratch, Graze)

• Injury where the superficial epithelial layer is removed by friction or compression.
• Types of Abrasions:
  • Pressure (imprint) abrasions: Fingernail marks, ligature marks.
  • Friction (sliding) abrasions: Car accidents.
  • Patterned abrasions.

Medico-Legal Importance of Abrasions

• Often indicate struggle and resistance, as they take the shape of the causative instrument.
• Common shapes and their causes:
  • Semilunar abrasions: Fingernails (throttling/smothering).
  • Rope marks: Rope (hanging/strangulation).
  • Sliding abrasions: Dragging (car accident).
  • Tyre impression: Tyre (car accident).

Abrasions: Types

• Human bites: Two curved rows of teeth marks.
• Animal bites: Two parallel rows of teeth.

Abrasion Location

• Occur at the site of force application, and may be the only visible trauma evidence.

Abrasion Healing Stages

• Four stages:
  • Scab formation: Immediate visible skin damage.
  • Epithelial Regeneration: Skin starts to regenerate.
  • Sub-epithelial granulation and epithelial hyperplasia: These processes occur.
  • Regression of epithelium and granulation tissue: Regression occurs.

Abrasion Characteristics

• Immediately after injury: Reddish, tender, and oozing serous fluid.

Abrasion Healing Progression

• Day 1-2: Soft, brownish-red scab.
• About three days: Scab becomes brown-red and dry, consisting of exudates.
• Gradually (within a week): Scab dries and darkens in color.
• About one week: Scab falls off, leaving no scar.
• 2-3 weeks: Normal skin restored.

Antemortem vs. Postmortem Abrasions

• Antemortem: Occur before death, showing hyperemia, vital tissue reactions, and specific dermal damage under a microscope.
• Postmortem: Occur after death, lack hyperemia, vital reactions, and specific microscopic features, usually from dragging a dead body.

Bruises (Contusions, Ecchymoses)

• Hemorrhage into soft tissue due to ruptured blood vessels from blunt trauma.
• Can occur in skin and internal organs (lung, heart, brain, muscle).
• Severity depends on force, tissue structure, and vascularity.

Medico-Legal Importance of Bruises

• Bruising can reflect the impact of force, but size is influenced by factors:
  • Force of trauma
  • Size of striking object
  • Age
  • Sex
  • Health condition
  • Site and type of tissue struck.

Bruising: Factors Influencing Size

• Children and elderly: More easily bruised due to thin skin and loss of subcutaneous support.
• Women, especially if obese: May bruise more easily.
• Well-conditioned, muscular individuals: More resistant to contusions.

Location and Direction of Bruises

• Does not necessarily pinpoint injury origin.
• Bleeding follows the path of least resistance, influenced by gravity and movement:
  • Blow to the temple: Bruise on cheek.
  • Jaw fracture: Bruise on neck.
  • Hip fracture: Bruise on thigh.
  • Blow to the forehead: Bruise on eyelids.
  • Blow to the lower abdomen: Bruise on scrotum or labia.
• Scalp bruises may be invisible externally unless there is swelling.
• Bruises are harder to detect in darker skin tones.

Bruising Patterns and Shapes

• Bruises may reflect the shape of the impacting object.
• Example: Grooves or ridges can match the pattern of the object.

Bruise Age and Color Changes

• Color changes are due to hemoglobin breakdown.
  • 2 days: Red (oxy Hb).
  • 3 days: Blue (reduced Hb).
  • 2 weeks: Green (biliverdin).
  • 3 weeks: Yellow (bilirubin).

Factors Affecting Bruise Characteristics

• Adequate lymphatic and venous drainage: Affects resolution.
• Size and depth of the bruise: Larger or deeper bruises take longer.
• Anatomical site: Influenced by local blood flow.
• Age and general health: Affect healing.

Medical Conditions Causing Bruises

• Sternal and cardiac massage: Result in bruising on the sternum and heart area.
• Needle puncture marks: Bruising around the area of the puncture.

Subconjunctival Bruises

• Appear initially bright red, but fade due to phagocytic removal of red blood cells.

Antemortem vs. Postmortem Bruises

• Antemortem: Before death.
• Postmortem: After death, usually caused by a significant trauma within hours of death.

This quiz covers the definitions, types, and classifications of wounds. It distinguishes between simple and dangerous wounds and discusses severity factors that affect healing. Understand the differences in terms of legal classifications and clinical implications.