Forensic aspects of trauma

Question 1

What dictates the mechanisms of injuries?

What can excessive mechanical force cause?

Answer 1

Force of impact
Area over where the force acts

Compression
Traction
Torsion
Tangenital (shearing)

Question 2

How are injuries classified?

Answer 2

Appearance or method of causation (abrasion, contusion, laceration, incised wound, gunshot wound)

Causation (suicidal, accidental, homicidal)

Nature of injury (blunt force, sharp force, explosive force)

Question 3

What are blunt force injuries?

Answer 3

Ground, fist, foot weapon

Contusion- bruises
Abrasions
Lacerations

Question 4

What is a bruise?

What types of bruises are there?

Answer 4

Burst blood vessels within the skin

Stretching-
Comrpession-
Tramline-
Finger tip bruising

Question 5

What affects the extent of bruising?

Answer 5

Skin pigmentation
Depth and location
Fat (increased subcutaneous fat, bruise more easily)
Age- children, skin loose and delicate
Elderly- Blood vessels of skin poorly supported
Resilient areas- bum, abdomen

Coagulative disorders- thrombocytopenia, Von willibrands disease, haemophilia, liver disease (alcoholics), bone marrow disease

Question 6

What is an abrasian?

Answer 6

Graze, scratch, scraping of the ski surface

Question 7

What is a laceration?

Answer 7

Cut/split of skin due to crushing

Question 8

What causes a sharp force trauma?

Answer 8

Injury causes by any weapon with sharp or cutting edge. Can be superficial of penetrating

Incised wounds- caused by slash motion

Stab wounds- wounds resulting from thrusting motion
Wound depth greater than length of surface

Question 9

What are the characteristics of defensive injuries?

Answer 9

Blunt and sharp force

Passive- victim raises arms and legs for protection
Active- victim tries to weapon or attackers hand

Question 10

What are the characteristics of self inflicted injuries

Answer 10

Commonly sharp force
Sit of elecion- usually wrist/forearms, chest and abdomen
Parallel, multiple and tentative incsions

Question 11

What are the consequences of injury?

Answer 11

Depends on mechanical insult (blunt, sharp, homicide, suicide, accident etc
Nature of target tissue (head, chest, abdomen, fat)
Forces involved- high speed RTC, fall from height, kicking, stamping,punching. multiple vs single impacts

Question 12

What are the different of skull fractures

Answer 12

Linear

Depressed

Question 13

What are the various types of blood loss volumes and how do they affect prognosis?

Answer 13

35ml-symptomatic
40-50ml clinical deterioration, life threatening
80-100ml- commonly fatal due to increased ICP and herniation
150ml- fatal

Question 14

What is an extradural haemorrhage?

Answer 14

Collection of blood that forms between the inner surface of the skull and the outer layer of the dura which is often called the endosteal layer. Associated with middle meningeal artery

Question 15

What is a subdural heamorrhage?

Answer 15

Bleeding of the bridging veins of the skull. Bleeding occurs between the inner layer of dura and the arachnoid matter

Question 16

What is a subarachnoid heamorrhage?

Answer 16

Life threatening brain bleed

Question 17

What is a traumatic subarachnoid heamorrhage

Answer 17

Specific pathological entitity
Due to rapid rotational movement of head usually as the result of a single punch to the jaw/upper part of neck or head
Causes traumatic rupture of vessels at base of brain- most frequently distal portion of the intracranial vertebral arteries at the point where they cross the dura
immedifately unconcious and in cardiac arrest

Question 18

What is a diffuse brain injury?

Answer 18

diffuse axonal injury- no mass or lesion but a prologned coma

Traumatic axonal injury- damaged axons due to trauma