Forensic Aspects of Trauma 1

Question 1

What 2 factors does force vary with?

Answer 1

Mass of object and square velocity of impact

Question 2

What does kinetic energy equal?

Answer 2

kinetic energy = 1/2 mass x velocity(squared)

Question 3

What else should be considered when looking at injury-causing forces?

Answer 3

The area over which the force acts

Question 4

What can excessive mechanical force cause (4)?

Answer 4

• Compression
• Traction
• Torsion
• Tangential (shearing)

Question 5

What does resultant damage depend on?

Answer 5

Type of mechanical insult AND nature of target tissue

Question 6

How may the appearance/method of causation of a wound be classified?

Answer 6

• Abrasion
• Contusion (bruise)
• Laceration
• Incised wounds
• Gunshot wounds
• Burns

Question 7

How may the manner of causation of a wound be classified (3)?

Answer 7

• Suicidal
• Accidental
• ˙Homicidal

Question 8

How may the nature of an injury be classified (3)?

Answer 8

• Blunt force
• Sharp force
• Explosive

Question 9

What are blunt force injuries caused by?

Answer 9

Caused by impact with blunt object

Question 10

How might blunt force trauma appear on the skin (3)?

Answer 10

• Contusions (bruises) - Burst blood vessels in skin
• Abrasions (graze, scratch) - Scraping of skin surface
• Lacerations (cut, tear) - Tear/split of skin due to crushing

Question 11

What factor affect prominence of a contusion mark?

Answer 11

• Skin pigmentation
• Depth and location – occur more readily over loose skin – eyebrow, scrotum
• Fat - ↑ subcut fat -> bruise more easily
• Age - Children - skin loose and delicate, Elderly - blood vessels of skin poorly supported
• Resilient areas – buttocks, abdomen – bruise less easily with given impact than areas with underlying bone which acts as an anvil with skin between bone and inflicting object
• Coagulative disorders – thrombocytopenia, Von Willebrand’s disease, haemophilia, liver disease (alcoholics), bone marrow disease

Question 12

What are abrasions?

Answer 12

Graze/scratch

Question 13

What is a laceration?

Answer 13

Cut/tear/split of the skin due to crushing

Question 14

What is sharp force trauma?

Answer 14

Injury caused by any weapon with sharp cutting edge - superficial or penetrating

Question 15

What are incised wounds?

Answer 15

• Superficial sharp force injury caused by slashing motion

* Longer on the skin surface than it is deep

Question 16

What are stab wounds?

Answer 16

• Penetrating sharp force injury resulting from thrusting motion
• Wound depth greater than length on the surface