Medicine - Injuries to different regions of the body

Question 1

Types of head injuries (scalp and skull)

Answer 1

• Scalp
  o Lacerations
• Skull
  o Mainly bone – designed to protect your brain
  o Skull made up of - Vault, base and face
  o Linear/Simple fracture
   Fractures can be caused from falling backwards – bone cracks from point of impact down to base of skull
  o Depressed fracture
   Hit hard enough to drive skull into brain
   Indicates a concentrated force – usually a weapon e.g. a hammer

Question 2

Inside the skull (intracranial) - bleeding in and around the brain

Answer 2

 Brain series of folds surrounded by membranes and nerves
 Three membranes – pia mater, arachnoid mater (thin and see-through), dura mater (outermost, and tough layer, designed to protect brain from skull)
 Membranes are crucial in classification of bleeding inside the skull
 Bleeding comes from blood vessels
* Arteries supply blood under pressure
* Veins drain blood from an organ
 In brain – blood comes in at base of brain, vessels then carry blood into the brain
* Blood vessels of the skull itself – bone is live substance that needs blood supply
* Blood vessels of the brain itself (arteries and veins)
* Three main blood vessels of the brain
o Arteries supplying blood to the skull
o arteries supplying blood to brain
o veins taking blood away from the brain

Question 3

Extradural haemorrhage (7 points)

Answer 3

• 3% of head injuries
  o Only occurs in a specific way – has to occur at site of skull fracture, skull fractures occur at site of blunt impact or blow
  o Blood vessels are at side of head so this occurs by blow to side of head
  o E.g. Punch to side of head
• Between skull and tough membrane that covers brain
• Mortality rate 10-40%
• 85% have skull fracture
• Damage to vessels of skull
  o Usually middle meningeal artery
  o Rapidly comes out of skull under pressure due to the artery being damaged
• Must open up skull and drain blood out to treat injury and cauterize blood vessels
• Deteriorate over number of hours – does not result in immediate unconsciousness

Question 4

Subdural haemorrhage (10 points)

Answer 4

• Violent acceleration of deceleration of the head – e.g. hitting head on pavement hard, pavement does not give any cushion
• Type of damage that occurs when shaking babies
• E.g. car crashes, being kicked
• If brain moves violently inside of skull, blood vessels can tear
  o Due to being veins, the blood comes out slowly
  o Can take days before it causes clinical problems
• 18% of head injures
• Frequently no skull fracture
  o Only need violent movement of the head
• Acute vs. chronic
  o Acute – occurs quickly
  o Chronic – takes long time to appear
  o Can take weeks for the injury to cause problems – may even forget even had an injury to the head before it causes problems
• Very young and very old
  o Very young – large heads with little muscle to support the head so brain moves violently inside skull
  o Very old – shrinkage of brain after 50 and so more room for brain to move in skull
  o Brain shrinks quicker in alcoholics – more susceptible to subdural haemorrhage
• Damage to veins draining blood from brain
  o Brain moves violently in skull and tears blood vessels
• Does not take instantaneous subconsciousness – it takes some time

Question 5

Subarachnoid haemorrhage (3 points)

Answer 5

• Rupture of artery supplying blood to the brain
• Causes
  o Usually natural disease – aneurysm
   An aneurysm is a pre-existing weakness in the vessels - a bulge
   If rupture, causes a haemorrhage
  o Sometimes due to cortical “bruising”
  o Rarely trauma to subarachnoid vessels
• Blow to side of head – can cause blood vessels to twist and rupture aneurysm

Question 6

Intracerebral haemorrhage (3 points)

Answer 6

• Bleeding inside the brain
• Comes from blood vessels in the brain
• Causes
  o Usually natural disease – a stroke
  o Can be due to trauma – skull bashes against brain violently causing bleeding in brain, or tearing of blood vessels

Question 7

Summary of brain haemorrhages

Answer 7

• Extradural haemorrhage – vessels of the skull
• Subdural haemorrhage – veins draining blood from the brain
• Subarachnoid haemorrhage – arteries supplying blood to the brain
• Intracerebral haemorrhage – vessels within the brain

Question 8

Why is bleeding inside the skull bad for you? (extradural, subdural and subarachnoid)

Answer 8

Extradural and subdural haemorrhage
- Leads to increased intracranial pressure (the more blood, the more pressure. Blood finds it more difficult to get to brain and blood supply limited
- Leads to distortion of the brain (problems with eyesight due to swelling, brain stem gets pushed into foramen magnum causing blood supply to be compromised and brain stem dies)

Subarachnoid haemorrhage
- Leads to meningeal irritation
- Leads to cardio-respiratory arrest (brain shuts down so rest of body shits down)

Question 9

Brain damage (direct intrusion, closed head injuries - primary and secondary)

Answer 9

 Direct intrusion
* Missile; skull fragments
 Closed head injuries
* Primary
o Surface
 Cerebral contusion – bruise
* Brain damaged by being bashed against skull
 Cerebral laceration – tear
* Split surface of brain – direct impact between brain and skull
o Deep
 Long thin structures get torn as the brain twists
 Not usually impacted from direct trauma but from the brain moving
 Long thin structures in the brain are:
* Blood vessels - Intracerebral haemorrhage
* Nerve fibres (axons) - Diffuse axonal injury
o Damage to nerve fibres in multiple locations in the brain – occurs in concussion
o Nature – microscopic lesions scattered within Central Nervous System
o Cause – shear stress due to rotational forces
* Secondary
o Cerebral oedema (swelling) – extradural or subdural haemorrhage
o Intracerebral haemorrhage (bleeding)

Question 10

Chest injuries - blunt trauma

Answer 10

o Impact
o Fractures of ribs of sternum
o May be complicated by
 Flail chest – compromises efficiency of breathing
 Pneumothorax – ribs dig into lung and air leaks into chest cavity
o Abdominal injuries
 Intestines and mesentery
 Liver
 Spleen

Question 11

Chest injuries - compression

Answer 11

o Chest has to be able to move and so if cannot move and is compressed, you cannot breathe
o Ribs must be able to move to allow breathing
o Injury caused is same as blunt trauma

Question 12

Chest injuries - penetration

Answer 12

o Stabbing
 Internal haemorrhage
* Heart, great vessels
 Pneumothorax
o Rib fractures

Question 13

Abdominal injuries - blunt trauma

Answer 13

o Intestines and mesentery
o Liver
 CPR can split liver – done to save life but can cause other injuries
o Spleen
 Can occur in car crash but also assault of kicking

Question 14

Abdominal injuries - penetrating injuries

Answer 14

o Viscera
o Large vessels