Pathology of Head Injury

Question 1

Basic injury types

Answer 1

Bruises 
Abrasions
Lacerations
Incisions
Thermal injuries

Question 2

Definition of injury

Answer 2

The transfer of energy to tissue

Question 3

What causes bruises?

Answer 3

Blunt force

Question 4

Pathology of a bruise

Answer 4

Damaged little blood vessels
The blood ooses into the subcutaneous tissue and you get a bruise
They diffuse after

Question 5

What is a black eye?

Answer 5

Peritorbital contusion

Question 6

Pathology of a black eye

Answer 6

Blood will tract within the tissues (mainly under gravity) through looser tissues and plains that it can move. Looser tissues in the eyes allow for the blood to accumulate around the eye - leading to a black eye

Question 7

What do symmetrical black eyes indicate?

Answer 7

Immediate suspicion of a deeper injury up into the base of the skull or further up

Question 8

What is an abrasion or graze?

Answer 8

Injuries to superficial parts of the skin

Question 9

Do abrasions/grazes tend to scab?

Answer 9

No

Question 10

Types of lacerations

Answer 10

Tears

Splits

Question 11

What causes lacerations?

Answer 11

Blunt force injuries

Question 12

Types of incised wounds

Answer 12

Cuts

Incisions

Question 13

What causes incised wounds?

Answer 13

Sharp force injuries

Question 14

What would a smaller energy injury cause?

Answer 14

Bruising or abrasion

Question 15

What would a bigger energy injury cause?

Answer 15

Laceration or incision

Question 16

Pathology of incision

Answer 16

Energy is delivered over a very small area e.g. blade of a knife creating a true cut

Question 17

Types of skull fractures

Answer 17

Ring fracture
Fissure fracture
Depressed fracture (“sign”)
Hairline fracture

Question 18

Pathology of a ring fracture of the skull

Answer 18

Force travels in the bone from the area of the force
Very considerable energy is put into the skull
The fracture will spread out and cause a ing
Diastases - sutures can be caused to break

Question 19

What parts of the skull are especially susceptible to ring fractures?

Answer 19

Where weaker bones meet stronger bones

Question 20

What are fissure fractures usually a result of?

Answer 20

Blunt force

Less energy

Question 21

Do hairline fractures usually require treatment?

Answer 21

No

Question 22

Are hairline fractures obvious?

Answer 22

No - barely visible

Question 23

Pathology of a depressed fracture

Answer 23

Localized force to the skull
Little piece of bone has been pushed inwards due to application of the force
Shape will match the cause of the force

Question 24

Function of pia mater

Answer 24

Retains configuration of the brain

Question 25

Function of dural sinuses

Answer 25

Venous drainage

Question 26

Types of intracranial haemorrhage

Answer 26

``` Extradural (epidural) Subdural Subarachnoid Cortical contusion Intracerebral haemorrhage Diffuse (axonal) injury ```

Question 27

Cause of extradural haemorrhage

Answer 27

Bleeding arteries

Question 28

What do 90% of people with extradural haemorrhages have associated with them?

Answer 28

Skull fracture

Question 29

Where is the bleeding in a subdural haemorrhage?

Answer 29

Between dura and arachnoid

Question 30

Pathology of subdural haemorrhage

Answer 30

In an injury - the skull stops moving but the brain keeps moving The little veins that transverse the dural space are stretched and they overcome the tensile strength and burst - leading to bleeding. Accumulation of venous pressure blood in the subdural space

Question 31

Who is more susceptible to a subdural haemorrhage? Why?

Answer 31

Brain shrinkage - alcoholics - elderly They have more space for stretching their veins

Question 32

Where does a subarachnoid haemorrhage occur?

Answer 32

Between arachnoid and pia

Question 33

Types of subarachnoid haemorrhage

Answer 33

Spontaneous | Traumatic

Question 34

Causes of a spontaneous SAH

Answer 34

Ruptured berry aneurysm

Question 35

Causes of traumatic SAH

Answer 35

Specific form caused by sudden movements of the head with an accelerational AND rotational component

Question 36

Which artery is often damaged in a traumatic SAH?

Answer 36

Vertebral artery

Question 37

Pathology of cortical contusion

Answer 37

Accelerational/decelerational head injuries

Question 38

Types of cortical contusion

Answer 38

Coup | Contrecoup

Question 39

What is a coup cortical contusion?

Answer 39

Where the head strikes and the direct blow occurs to the head - there will be a contusion there on the brain - this is where the coup injury is

Question 40

What is a contrecoup cortical contusion?

Answer 40

Further cortical contusion opposite to the original injury site Injury at frontal or even temporal poles

Question 41

Causes of intracerebral haemorrhage

Answer 41

``` Natural disease - HTN - AV anomaly (e.g. vascular tumours) - amyloid angiopathy (in elderly - vessels become very delicate) Traumatic injury ```

Question 42

Pathology of diffuse (axonal) injury

Answer 42

When there is big accelerational/deceleration force that imply a certain rotation and makes the brain completely disrupted All of the neurones suffer Sometimes so much energy delivered to the brain that death can be intraosseous Global disruption to the brain

Question 43

What causes a subdural injury?

Answer 43

Damage to the bridging veins between the cortex and the venous sinuses

Question 44

Damage to the MMA results in what?

Answer 44

Extra dural haematoma