Meninges and Dural folds Flashcards
List the three brain coverings?
Dura Arachnoid Pia
Which meaning is a tough fibrous membrane?
Dura
Which meninge is microscopically thin and very closely adhered to the surface of the brain?
Pia
Describe the arachnoid.
Soft translucent membrane under the dura
What is in the subdural space?
Nothing its just a potential space
The subarachnoid space carries what?
CSF, arteries and veins for the brain
The dura is tightly adhered to the ….. table of bone, but some blood vessels like the ….. artery run just above the dura.
inner middle meningeal
What are the two dural layers?
Periosteal - endosteum that lines the inner surface of the inner table of bone Meningeal- the layer adjacent to the arachnoid
Where do the two dural layers seperate?
To form dural folds and venous sinuses
Label the image below
Why do we need dural folds?
Rigid dividers of the brain which help stability
What problems do dural folds pose in the case of raised intercranial pressure?
Compression and siplacement of the brain against a rigid fold could lead to herniation
What is seen at the bordered of the falx cerebri, flax cerebelli and on the cranial floor?
Dural venous sinuses
Which dural venous sinus is connected to the eye and is located close to the chiasm and several cranial nerves pas through it?
Cavernous sinus
What do the dural venous sinuses drain from and to?
From cerebral veins to the internal jugular vein
What is the straight sinus?
The connecting venous sinus between the superior and inferior saggital sinuses at the level of the transverse sinus
What are bridging veins and why are they significant in head injuries of elderly patients?
Veins that connect the subarachnoids veins to teh dural veins.
With cerebellar atrophy of senility these veins will get weaker and more prone to rupture leading to subdural haematoma
List three types of intercranial haemorrhage.
Extradural (between dura and inner table of bone- lens shaped)
Subdural (banana shaped)
Subarachnoid
What is bleed with in the brain tissue itself called?
Intra-cerbral haemarrhage (contusions or tonr white matter)
Why do we worry about the increase in volume from a bleed in the brain?
Raised ICP could lead to brain tissue damage, brain stem injury etc
What type of vessel bleeds in extradural haemorraheges?
Artery
What limits extra dural heamorhhages?
Suture lines
What type of blood is seen in subdural haemorrages?
Venous blood - bridging veins from dural venous sinus
Why don’t subdural haemorrhages cross the midline?
Falx cerebri
A patient presents with sudden onset worst headache of there life, feels like theyve been wacked on the back of the head and the pain is radiating forward. No actual history of head trauma though.
Whats this a typical presentation for?
Subarachnoid haemorrhage
How do subarachnoid haemorrahges develope spontaneously?
Aneurysm usually at circle of willis ruptures. Arterial blood in subarachnoid space mixes with CSF.
How do you examine for subarachnoid?
Head CT ASAP (100% seen within 6hrs but 7% missed at 24 hours)
Lumbar puncture if CT inconclusive
List connections of venous blood from dural sinuses
Bridging veins into subarachnoid space
Diploic veins into skull
Emissary veins into scalp loose CT
