14.11 Gunshot Wounds

Question 1

Entrance wound

Answer 1

• The changes caused by the bullet, and
• The changes caused by the components that leave the barrel of the gun, other than the bullet.
• The changes to wounds that are not caused by the bullet or components that leave the barrel of the gun, other than the bullet.
  Inserted diagram NB

Question 2

Changes caused by bullet

Answer 2

The central, punched out defect
- round or elliptical in shape
- usually smooth edges, but might be lacerated
- often filled with blood/brain/tissue
- usually smaller than circumference of bullet due to elasticity of the skin

The abrasion ring
- Caused by bullet abrading the epidermis when Ek of bullet overcomes elastic energy of skin and punches through
- 2-5mm around central defect
- When fresh, or kept wet: light pinkish colour. When dried out: brown or black
- (refer also atypical or shored exit wounds)

The grease ring / smudge ring or dirt collar
- on the inner margin of the abrasion ring
- Not seen, as is due to substances that cling to the bullet and rub of on skin (oil, rust, soot). More common in black powder weapons
- 0,5-1mm wide
- More often seen on clothing / intermediate targets

Contusion
- Skin and subcutaneous tissue
- Tends to fade towards the periphery
- Also present at exit wound

Surrounding defects
- Due to intermediate target fragments (from glass or wood)

Question 3

Changes caused by the components that leave the barrel of the gun, other than the bullet. (see diagram in notes)

Answer 3

Remember the following five components in order of their weight from lightest to heaviest:
• Heat
• Gas
• Smoke
• Soot
• Burning and / or unburnt particles of propellant

Heat and Gas
- This causes
• Burning of the skin
• Hair loss
• ‘Pin head’ appearance of the hair
• The distance on which the effects of heat can be seen on the skin is about 10-20 mm away from the gun

Smoke and Soot
- This causes
• Greyish / Black discolouration (deposition) around and in wound.
• Distance once again varies according to Di Mayo (20-30 cm) and according to Knight ± 15 cm. This once again is for hand weapons. For shoulder weapons the values must be doubled.
• Can be washed off the skin.

Burning and / or unburnt particles of propellant
- This causes
• Tattooing(referalsopeppering,specklingetc.).
• Ante mortem phenomena
• Distance: ± 50 cm (Knight - hand weapons)

Question 4

Changes to wounds that are not caused by the bullet or components that leave the barrel of the gun, or the bullet.

Answer 4

• Pieces of clothing can be present in wound.
• ⬆️[CO] than at exit wound.
• Usually smaller than exit wound.

Question 5

Characteristics of exit wounds

Answer 5

1. Shapes vary widely e.g.
   - Irregular and torn
   - Ragged appearance
   - Lacerated shape or
   - Sometimes a round shape
2. Surrounding bruising may be present
3. May exhibit a collar of abrasion (atypical or shored exit wound)
4. No smudge ring

Also:

5. No singeing, soot deposotion, tattooing
6. ⬇️ [CO] than in entrance wound
7. No clothing / foreign material in wound
8. Borders sometimes bevelled outwards (be careful)
9. Usually larger than entrance wound due to bigger contact area and secondary projectiles like bone.

Question 6

Contact gunshut wounds

Answer 6

• gun directly placed on the skin
• Overlying bony tissue (e.g. skull) causes stellate, torn type of wound, sometimes with imprint abrasion. This is due to gas cavity formation between skin and bone.
• Over non-bony areas (e.g. abdominal wall, thigh)
• Sometimes imprint abrasion wound (especially with high velocity firearm. Wound usually not torn.

Question 7

Shotgun wounds

Answer 7

Slide 28-31

• the closer you are to the gun, pallets will still be a tight group (therefor it will be a single hole)

Question 8

Explosion injuries

Answer 8

Mechanism of death
1. Explosion mechanism
2. Impact of the projectile from the source (e.g. pieces of the bomb that fly through the air)
3. Secondary impact that follows explosion (e.g. loose standing items that turn into missiles due to explosion).
4. Burn wounds: Gas/fire
5. Collapse of buildings

Explosion mechanisms
1. Lung pathology: Bleeding/lacerations of the lungs. The mechanism of development is unclear (? Transcutaneous /? Via airway)
2. GIT: Bleeding, perforation, retroperitoneal haemorrhage, and lacerations of solid organs
3. Damage to ears
4. Arterial air embolism