Forensic Trauma

Question 1

Trauma can be applied by 4 basic mechanisms?

Answer 1

• Compression
• Traction (pulling)
• Torsion (Twisting)
• Tangential (Shearing)

Question 2

What are the 3 major categories we use to describe an injury?

Answer 2

• Appearance/method of causation
• Manner of causation e,g, self-inflicted, accident or homicide
• Nature of injury e.g. blunt or sharp force

Question 3

What are the types of blunt force injuries?

Answer 3

• Contusions
• Abrasions (scrapes)
• Lacerations (tear/split in skin due to crushing)

Question 4

Describe some common Contusions Patterns?

Answer 4

• Shoe Treads
• Tyres
• Belt buckle shapes
• FIngers
• Tramline

Question 5

What is tramline bruising?

Answer 5

Impact of a rod-like object pushing blood to either side causing a long area of pallor with strips of bruising to either side

Question 6

What factors effect prominence of bruising?

Answer 6

• Skin pigmentation
• Depth & Location
• Fat (more subcut fat = more bruising)
• Age (kids and elderly)
• Resilient areas (e.g. buttocks wheres no bone to act as an anvil)
• Coagulative Disorders

Question 7

How can we observe an abrasion to learn more about the injury?

Answer 7

skin tags can indicate the direction of the force

Also the pattern of the abrasion can determine the instrument used

Question 8

What are the different types of sharp force wounds?

Answer 8

Incised - Slashing motion creates a superficial wound longer than it is deep

Stab - thrusting motion creates a penetrating wound deeper than it is long

Question 9

What can we tell form the pattern of a stab wound?

Answer 9

Different types of instrument e.g. scissors, screwdrivers and knives all look different.

If a knife is double or single bladed

Somtimes the surrounding bruise can indicate the shape of the hilt (if it went all the way in)

Question 10

What are the types of defensive injuries?

Answer 10

• Passive where the victim raises arms/legs for protection

- Active where the victim tries to grab the weapon or the attackers hand

Question 11

How do passive and active defensive injuries look different?

Answer 11

Passive shows slices with skin flaps on the back of the hands and forearms

Active shows sliced, shelved wound on the palm & webspaces (mostly the 1st web space)

Question 12

What appearances would suggest a wound to be self-inflicted?

Answer 12

• Common type/place i.e. sharp force wound to wrists, chest and abdomen
• Parallel wounds, multiple wounds and tentative incisions
• If clothes have been lifted prior to the stab

Question 13

What factors affect the consequence of an injury

Answer 13

1- Type of insult e.g. sharp or blunt
2- Target tissue e.g. fat/muscle vs important vessels/organs
3- Force e.g. a high speed RTA vs just falling
4- No. of impacts

Question 14

Patient presents dead at the scene after being punched to the side of the jaw, what likely happened?

Answer 14

Punch causes a rapid rotation of the neck which ruptures the vertebral arteries as the cross the dura leading to subarachnoid haemorrhage, along with axonal injury to the brainstem resulting in immediate cardiac arrest

Question 15

Patient presents with an intracranial bleed after RTA, whats the likely course the injury took?

Answer 15

Sudden change of direction of motion in an RTA often causes the brain to pull the bridging veins apart resulting in a subdural haemorrhage

Question 16

PAtient presents with a depressed fracture to their temple and signs of rising ICP, whats happened?

Answer 16

the injury to the temple has ruptured the middle meningeal artery resulting in an extradural haemorrhage

Question 17

Define the difference betweeen Diffuse Axonal Injury and Traumatic Axonal Injury?

Answer 17

Often used interchangeably but:

• DAI is CLINICALand refers to any case with immediate prolonged coma without apparent mass lesion of metabolic abnormality
• TAI is pathological and refers to when axons are damaged by trauma, it can be diffuse or focal

Question 18

What can we tell from a patients injuries after an RTA?

Answer 18

Can tell an RTA often from the specific safety glass wounds.
Can tell if a patient was driving by the pattern of steering wheel bruise/fractures
Can get some idea of the size/shape of the car from a pedestrians injuries

Question 19

How can we tell if there have been post-mortem injuries?

Answer 19

Lack of vital reaction and parchmentation

Question 20

Volume of blood lost and outcome

Answer 20

35mls: symptomatic

40-50mls: clinical deterioration, life threatening

80-100mls: commonly fatal due to increased ICP and herniation

150mls+ fatal