Sharp Force Trauma

Question 1

Define, “Sharp Force Trauma”

Answer 1

• Wounds caused by pointed / sharp-edged weapons

Question 2

What are the Characteristics / Attributes of SFT?

Answer 2

• Slit-like shape
• Smooth, Clean Margins
• Pointed Ends
• XS Bleeding
• Absence of Tissue Bridges

Question 3

What are the 3 Types of SFT?

Answer 3

1) Stab + Puncture Wounds, aka penetrating injuries

2) Incised Wounds

3) Chop Wounds

Question 4

Define Penetrating Injuries

Answer 4

• 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

Question 5

What are the Types of STAB Wounds?

Answer 5

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

Question 6

What does the Size / Shape of a Stab Wound depend on?

Answer 6

• Nature of Blade
• Type of Knife
• Direction of Thrust
• Movement of Blade, in the Wound
• Movement of the Stabbed Individual

Question 7

At What Circumstances is the Wound Length LESSER < than Blade Width?

Answer 7

• 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

Question 8

At What Circumstances is the Wound Length GREATER > than Blade Width?

Answer 8

• 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

Question 9

What are the Different Shapes of Stab Wounds?

Answer 9

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

Question 10

What is the Mechanism of Production of a Puncture Wound?

Answer 10

• 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

Question 11

Define “Puncture Wound”

Answer 11

• Type of Piercing wound
• Produced by blunt-pointed objects - screwdriver / scissors / fork

Question 12

What are Langer’s Lines?

Answer 12

• Influence the appearance of a wound on the skin
• Pattern of elastic fibres in the dermis of skin

Question 13

What are the Types of Wounds through Langer’s Lines?

Answer 13

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

Question 14

Define “Incised Wounds”

Answer 14

• 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

Question 15

What is the Mechanism of Production of Incised Wounds?

Answer 15

• Pressure / Friction of Sharp Edge AGAINST the Surface of the Body

Question 16

What are the Characteristics of Incised Wounds?

Answer 16

• 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

Question 17

What are the Shapes of Incisions?

Answer 17

• Fissure / Spindle-like Shape
• Zig-Zag
• Cresenteric

Question 18

What is Tailing?

Answer 18

• 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

Question 19

Define “Chop Wounds”

Answer 19

• Heavy object with a sharp edge - such as machete, or axe
• Produced by hacking motion

Question 20

What are the Characteristics of Chop Wounds?

Answer 20

• Fissure-like Shape
• Great Size
• Slightly abraded Margins
• Fracture of Underlying Bones
• Destruction of Underlying Organs

Question 21

What are the 2 Medico-legal Rules?

Answer 21

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

Question 22

What are the Complications from SFT?

Answer 22

• Shock = Due to external / internal bleeding
• Air Embolism = IF Neck Structure is involved
• Asphyxia = From aspirated blood
• Cardiac Tamponade
• Hemo - Pneumothorax

Question 23

Define “Defence Wounds”

Answer 23

• 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

Question 24

Define “Hesitation Wounds”

Answer 24

• Self-inflicted sharp-force injury
• Usually superficially incised or stab wound
• On the neck, wrists + chest
• Indicate SUICIDE