2.2 Meningeal Layers, Dural Folds and Dural Venous Sinuses Flashcards
What are the meninges?
Three membranous layers that surround and protect the brain
Name the meningeal layers
Dura
Arachnoid
Pia
What can be found in the subarachnoid space?
CSF and cerebral blood vessels
What are the two layers of dura called?
Periosteal
Meningeal
What does separation of the dural layers create?
Dural folds
Dural venous sinus
Where do the dural venous sinuses drain to?
Internal jugular vein
Name the main dural folds
Falx cerebri
Tentorium cerebelli
What is the role of dural folds?
Help stabilise the brain
Act as rigid dividers
What is a problem with dural folds?
Rise in ICP may lead to herniation
What are dural venous sinuses?
Venous blood filled spaces created by separation of meningeal from periosteal layer of dura
Where do cerebral veins within the subarachnoid space drain into?
Dural venous sinuses
What space do the bridging veins traverse?
Subdural space
What is an intracerebral haemorrhage?
Bleeding within the brain tissue itself
What type of bleed is an extradural haemorrhage?
Arterial
What shape bleed does an extra dural haemorrhage produce?
Lens
What type of bleed is a subdural haemorrhage?
Venous
Why does increasing age increase the likelihood of a subdural bleed?
Brain shrinks Bridging veins (between arachnoid and dural layers) are longer and under more tension so are more easily sheared
What shape bleed is produced by a subdural haemorrhage?
Banana
What causes a subarachnoid haemorrhage?
Secondary to trauma
Spontanous rupture of a blood vessel
What type of bleed is a subarachnoid haemorrhage?
Arterial
Which vessels are usually involved in a subarachnoid haemorrhage?
Circle of willis
What happens in a subarachnoid haemorrhage?
Blood leaks into the subarachnoid space, mixing with CSF
Sudden and often fatal
What can be done if a CT is inconclusive in diagnosing a subarachnoid bleed?
Lumbar puncture
Look for evidence of blood degradation products
