Effects of physical injury

Question 1

Local damage

Answer 1

Disruption of tissue

- Scraping
- Squashing
- Twisting 

Interruption of function

- Strangulation 
- Traumatic asphyxia - chest = compressed

Question 2

Haemorrhage (bleeding)

Answer 2

Can be to outside world or internally

Damage to any blood vessel will cause bleeding, more damage if to arteries than veins as blood is under pressure and will come out more rapidly

Forensic issues:

- Susceptibility - some ppl bleed more readily than others
- Cause of incapacity - blood pressure falls and person = unconscious 
- Cause of death
- Contamination of scene and assailant - forensic POV

Question 3

Susceptibility

Answer 3

Bleeding = limited mainly by blood clotting
Blood clotting relies on two systems - platelets from bone marrow, clotting factors from liver

Increased susceptibility:
Liver disease (cirrhosis) - cannot clot blood properly - bleed more readily
Bone marrow disease (leukaemia)
Medications (aspirin) - most common

Question 4

Cause of incapacity

Answer 4

Clinical assessment:

Normal to hypotensive to shock then organ damage/death

At first speeds up heart and shuts down organs which you don’t need minute to minute, to prioritise blood where needs it

Shock = blood pressure not being maintained to perfuse organs (organs suffer)

Blood loss = internal and external, sig blood loss = internal

Question 5

Cause for death

Answer 5

• Dangerous sites (intracranial, airway, pericardial sac)
  
  • Volume lost
  • Speed of loss
  • Medical measures taken: delayed death, unclear intention

Question 6

Contamination

Answer 6

Most with blunt injury - scene can be important when interpreting injury

Arterial blood = high up and sprays everywhere

Question 7

Infection

Answer 7

Local - at injury site

Treatment of local = debridement (getting rid of dead tissue), antiseptics, dressing and antibiotics

Distant- pneumonia/urinary tract infection

Forensic issues - cause of death (especially if delayed) esp in old ppl

Question 8

Embolism

Answer 8

Embolism - process
Embolus - noun

Something floating in blood from one place to another lodging then blocking a vessel

Types of emboli: all relevant to trauma

- Thrombus - blood clot e.g. endocarditis 
- Fat 
- Air
- Foreign body

Question 9

Thromboembolism

Answer 9

1. Immobility - blood flow in leg veins reduced - thrombosis of deep calf veins (DVT)
   
   2. Any tissue injury - pours platelets into bone marrow - higher blood coagulability - thrombosis of the deep calf veins (DVT)

Most dangerous place = in legs (if post trauma and swollen calf seek med attention) - then floats into heart, pumped into lungs and can be fatal/infarct

Peak risk = 10/14 days after trauma

Question 10

Fat embolism

Answer 10

Fat released from site of fracture/soft tissue ( bone marrow when bone crushed) die to crush injury - travel through blood vessels to lungs - enters systemic circulation (brain, kidneys, skin, heart)

Semi fluid - to a degree go through the lungs and go to different organs and damage them

Question 11

Air embolism

Answer 11

Causes:

- Opening of neck vein - neck = high up and air pressure = negative 
- Trauma
- Surgery
- Higginson syringe 
- Blood transfusion - more historic 
- Deep sea divers 

>100ml air needed
Fills right atrium and ventricle - air lock

Question 12

Foreign body embolism

Answer 12

Normally through injection esp intra venus drug users that arent meant to be injected e.g. mashed up tablets

Forensic relevance

- Common after trauma
- May be fatal
- May be delayed (thrombus)