Sharp Force Trauma Flashcards
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Define, “Sharp Force Trauma”
- Wounds caused by pointed / sharp-edged weapons
What are the Characteristics / Attributes of SFT?
- Slit-like shape
- Smooth, Clean Margins
- Pointed Ends
- XS Bleeding
- Absence of Tissue Bridges
What are the 3 Types of SFT?
1) Stab + Puncture Wounds, aka penetrating injuries
2) Incised Wounds
3) Chop Wounds
Define Penetrating Injuries
- Due to separation of skin / soft tissues
- UNDER PRESSURE of a sharp-pointed object
- Where DEPTH > Surface Length, as they’re caused by thrusting motion
What are the Types of STAB Wounds?
1) Penetrating Wound = Enters into cavity
2) Perforating Wound = aka through-n-through wounds where weapon enters the body on one side, and out of the other
What does the Size / Shape of a Stab Wound depend on?
- Nature of Blade
- Type of Knife
- Direction of Thrust
- Movement of Blade, in the Wound
- Movement of the Stabbed Individual
At What Circumstances is the Wound Length LESSER < than Blade Width?
- Straight in / out Wound = Due to stretching of skin over point of knife (insertion) / followed by elastic recoil (withdrawal)
- Knife is not fully inserted properly
At What Circumstances is the Wound Length GREATER > than Blade Width?
- Blade is inserted at an angle
- Rocking of knife upon withdrawal
- Movement of knife + victim, causes twisting of the knife blade - lengthening the wound
- Combo of Stab + Cut
What are the Different Shapes of Stab Wounds?
1) Double Pointed = Done by a double-edged knife - dagger
2) Triangular w/ Rounded End
3) Triangular w/ Blunt End
4) Fishtailing = Where blunt end of wound has small splits in skin
What is the Mechanism of Production of a Puncture Wound?
- Pierce / Separate the tissues in depth, via inversion, crushing + stretching on entry
- Leaving a circular-shaped wound, as well as abrasion / bruising of the edges
- a laceration-like wound
Define “Puncture Wound”
- Type of Piercing wound
- Produced by blunt-pointed objects - screwdriver / scissors / fork
What are Langer’s Lines?
- Influence the appearance of a wound on the skin
- Pattern of elastic fibres in the dermis of skin
What are the Types of Wounds through Langer’s Lines?
1) Gaping Wound = Stab wound is perpendicular to the fibres - pulling apart the edges of the wound
2) Narrow Slit-like Wound = Stab wounds are parallel to Langer’s Lines
3) Oblique Wounds = IN BETWEEN the two types
Define “Incised Wounds”
- aka, Cuts, which is a Clean Division of the tissues, due to sharp-edged instruments - such as knife, razor or broken glass
- Where Length > GREATER than Depth
What is the Mechanism of Production of Incised Wounds?
- Pressure / Friction of Sharp Edge AGAINST the Surface of the Body
What are the Characteristics of Incised Wounds?
- Clean-cut + Well-Defined Margins
- Edges are free from contusions / abrasions
- Absence of Tissue Bridges
- Width is > GREATER than Sharp-Cutting Edge
- Length is > GREATER than Width + Depth
What are the Shapes of Incisions?
- Fissure / Spindle-like Shape
- Zig-Zag
- Cresenteric
What is Tailing?
- Where Head of Wound is deeper = Due to more pressure exertion on knife
- Followed by shallow end = Due to knife leaving the tissues, cutting the skin at the end
- Indicates the direction and number of cuts
Define “Chop Wounds”
- Heavy object with a sharp edge - such as machete, or axe
- Produced by hacking motion
What are the Characteristics of Chop Wounds?
- Fissure-like Shape
- Great Size
- Slightly abraded Margins
- Fracture of Underlying Bones
- Destruction of Underlying Organs
What are the 2 Medico-legal Rules?
1) Best indicator of blade width and length is the:
- shortest (least twisting)
- deepest wound (weapon fully inserted).
2) Each wound requires approximation of its edges to determine a more accurate length
What are the Complications from SFT?
- Shock = Due to external / internal bleeding
- Air Embolism = IF Neck Structure is involved
- Asphyxia = From aspirated blood
- Cardiac Tamponade
- Hemo - Pneumothorax
Define “Defence Wounds”
- Due to immediate / instinctive reaction of the victim to save themselves
- Via raising the arm, or by grasping the weapon
- IF BLUNT = Bruises, Abrasions, Lacerations + Fractures are found on forearms / wrists / hands
- IF SHARP = Stab, Puncture, Incised + Chop are found on forearms / palms + fingers
- Indicate HOMICIDE
Define “Hesitation Wounds”
- Self-inflicted sharp-force injury
- Usually superficially incised or stab wound
- On the neck, wrists + chest
- Indicate SUICIDE
