Pathology of Head Injury Flashcards
Basic injury types
Bruises Abrasions Lacerations Incisions Thermal injuries
Definition of injury
The transfer of energy to tissue
What causes bruises?
Blunt force
Pathology of a bruise
Damaged little blood vessels
The blood ooses into the subcutaneous tissue and you get a bruise
They diffuse after
What is a black eye?
Peritorbital contusion
Pathology of a black eye
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
What do symmetrical black eyes indicate?
Immediate suspicion of a deeper injury up into the base of the skull or further up
What is an abrasion or graze?
Injuries to superficial parts of the skin
Do abrasions/grazes tend to scab?
No
Types of lacerations
Tears
Splits
What causes lacerations?
Blunt force injuries
Types of incised wounds
Cuts
Incisions
What causes incised wounds?
Sharp force injuries
What would a smaller energy injury cause?
Bruising or abrasion
What would a bigger energy injury cause?
Laceration or incision
Pathology of incision
Energy is delivered over a very small area e.g. blade of a knife creating a true cut
Types of skull fractures
Ring fracture
Fissure fracture
Depressed fracture (“sign”)
Hairline fracture
Pathology of a ring fracture of the skull
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
What parts of the skull are especially susceptible to ring fractures?
Where weaker bones meet stronger bones
What are fissure fractures usually a result of?
Blunt force
Less energy
Do hairline fractures usually require treatment?
No
Are hairline fractures obvious?
No - barely visible
Pathology of a depressed fracture
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
Function of pia mater
Retains configuration of the brain
Function of dural sinuses
Venous drainage
Types of intracranial haemorrhage
Extradural (epidural) Subdural Subarachnoid Cortical contusion Intracerebral haemorrhage Diffuse (axonal) injury
Cause of extradural haemorrhage
Bleeding arteries
What do 90% of people with extradural haemorrhages have associated with them?
Skull fracture
Where is the bleeding in a subdural haemorrhage?
Between dura and arachnoid
Pathology of subdural haemorrhage
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
Who is more susceptible to a subdural haemorrhage? Why?
Brain shrinkage
- alcoholics
- elderly
They have more space for stretching their veins
Where does a subarachnoid haemorrhage occur?
Between arachnoid and pia
Types of subarachnoid haemorrhage
Spontaneous
Traumatic
Causes of a spontaneous SAH
Ruptured berry aneurysm
Causes of traumatic SAH
Specific form caused by sudden movements of the head with an accelerational AND rotational component
Which artery is often damaged in a traumatic SAH?
Vertebral artery
Pathology of cortical contusion
Accelerational/decelerational head injuries
Types of cortical contusion
Coup
Contrecoup
What is a coup cortical contusion?
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
What is a contrecoup cortical contusion?
Further cortical contusion opposite to the original injury site
Injury at frontal or even temporal poles
Causes of intracerebral haemorrhage
Natural disease - HTN - AV anomaly (e.g. vascular tumours) - amyloid angiopathy (in elderly - vessels become very delicate) Traumatic injury
Pathology of diffuse (axonal) injury
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
What causes a subdural injury?
Damage to the bridging veins between the cortex and the venous sinuses
Damage to the MMA results in what?
Extra dural haematoma
