Gunshot wounds & Explosion injuries

Question 1

Name characteristics of a suicide.

Answer 1

Single shot
Vital organ
Usually not through clothes

Question 2

Describe the wounding ability of projectiles.

Answer 2

Velocity is more important than mass.
Max wounding when all Ek is released in the body (no exit wound) eg soft point projectiles.
Bullets which go through and do not fragment cause minimal wounding eg fmj.

Question 3

1. What does a cartridge consist of?

2. What is the function of a rifled barrel?

Answer 3

1. Bullet, propellant, primer and casing.
2. The grooves result in rotation of the bullet, providing stability. It leaves markings on the bullet which can be used to trace the weapon.

Question 4

What are the 3 components of entrance wounds?

Answer 4

1. Changes caused by the bullet
2. Changes caused by the other components leaving the barrel
3. Changes to the skin wounds, not caused by the above.

Question 5

What changes does the bullet cause in entrance wounds?

Answer 5

1. Central, punched-out defect (

Question 6

What changes do the barrel components, other than the bullet, cause to entrance wounds?

Answer 6

1. Heat and gas singeing (1-2cm) - skin burning, hair loss and pin head appearance of hair.
2. Smoke and soot (20cm) - Black deposition in and around wound that can be washed off.
3. Burning/unburnt particles of propellant (1m) - Tattooing with ante mortem phenomenon.

Question 7

1. What skin changesin entrance wounds (not caused by the barrel components) can occur?
2. What is the only way to correctly measure the distance of a gunshot?

Answer 7

1. Pieces of clothing can present in the wound, more CO and usually smaller than exit wounds.
2. By doing test shots.

Question 8

What are the characteristics of exit wounds?

Answer 8

1. Varying shape (irregular, ragged)
2. Contusion
3. Abrasion ring
4. No grease ring or satellited defects
5. No singeing, soot or tattooing
6. No pieces of clothing
7. Less CO than entrance wound
8. Bigger than entrance wound
9. Beveled outward

Question 9

Name 7 special findings in gunshot wounds.

Answer 9

1. Bullet hits at 90 - round abrasion ring with bruising.
2. Bullet hits at angle - elliptic abrasion ring with bruising on side of impact.
3. Contact gunshot wound over bony tissue - imprint abrasion, gas cavity formation with a stellate tear
4. Contact gunshot wound over soft area - imprint abrasion.
5. Grazing - abrasion, bruising or tear.
6. Re-entry wound - abnormal
7. Distant, high velocity wounds - more torn from yaw.

Question 10

1. Classify the distances of gunshots.
2. Comment on how the bullet velocity affects the tract.
3. What bone defects are caused by bullets?

Answer 10

1. Contact (heat), near (soot and tattooing), intermediate (tattooing), distant (no extra changes).
2. Low velocity only damages structures in path of the tract. High velocity also damages in the area of temporary cavity.
3. Beveling of margins in direction of bullet and splintering with small bone fragments in direction of tract.

Question 11

1. What can cause pseudo-tattooing?

2. What can cause pseudo-soot?

Answer 11

1. Missile fragments, fragments of intermediaries, insect bites, bleeding in hair follicles, medical manipulation and petechiae.
2. Oil, fingerprints, graphite, tar, dried abrasion ring and subcutaneous hemorrhage.

Question 12

1. Comment on the residue of gunshot wounds.

2. What tests are used to pick up primer residue?

Answer 12

1. Soot has carbon, gun powder has nitrates and primer residue has lead, barium and antimony.
2. Neutron-activated analysis (picks up barium and antimony, and needs a nuclear reactor), Flameless atomic absorption (picks up everything) and scanning electron microscopy (faster than FAAS).

Question 13

What leaves the barrel of a shotgun?

Answer 13

1. Lead pellets
2. Heat and gas
3. Smoke and soot
4. Burning and unburnt propellant particles
5. The wad: felt, cardboard and plastic.

Question 14

1. Comment on the defect caused by shotgun wounds fired from different distances?
2. Discuss some effects of shotgun wounds.

Answer 14

1. a) Single round defect <30cm, rat-eaten defect 30cm-1m, satellite defects around central defect >1m and only small defects >10m.
2. Uncommon to have exit wounds as low Ek, internal damage due to gas and mechanical effect and not temporary cavitation, and pellets disperse wider in the body once it hits the skin due to billiard effect.

Question 15

What are the mechanisms of death in explosions?

Answer 15

1. Explosion
2. Impact of a projectile from the source
3. Secondary impact following the explosion
4. Burn wounds
5. Collapse of buildings

Question 16

What are the mechanisms of injury in explosions?

Answer 16

1. Lung pathology - bleeding/lacerations
2. GIT - bleeding, perforation, retroperitoneal hemorrhage, organ lacerations
3. Damage to ears
4. Arterial air embolism

Question 17

1. What are the 3 waves of an explosion?
2. Through which mediums can injury take place?
3. State the clinical implications at autopsy.

Answer 17

1. Positive pressure wave, wave of mass movement and a negative pressure wave.
2. Air (lungs), water (GIT) and shock waves.
3. Victim identification, XR for identification of bomb fragments, confirm injury led to death.