Meninges, Venous Drainage and CSF Flashcards
Describe the assembly of the meninges
- Dura mater (tough fibrous bridges attached to skull),
- Arachnoid Mater (delicate, sealed ‘bag’ for csf),
- Arachnoid trabeculae (Helps hold brain in place),
- Pia mater (delicate, dips into sulci and has cerebral artery embedded in it).
Rupture of what artery is most likely to cause an extradural haematoma?
Middle meningeal artery, especially as this lies below pterion so
Name the cisterns on the following diagram. INSERT PIC
INSERT PIC
What is a likely cause of a subarachnoid haemorrhage?
Rupture of a berry aneurysm on the circle of Willis. Commonly seen on the posterior communicating artery
What are denticulate ligaments?
Extensions of pia mater which allows for stabilisation of the spinal cord while it is suspended
Why are the roots of the spinal cord long?
Early in development the S1 root origin is close to the S1 vertebra ect however as the vertebral column grows then the root of the nerve must extend down to it’s vertebral level as the end of the cord doesn’t grow to the same lenght
Where is the best place to take a lumbar puncture from?
Well below L2, usually L4/5
Label the following diagram
INSERT PIC
What veins drain into the straight sinus?
The internal cerebral vein and basal vein drain into the great cerebral vein which drains into the straight sinus, as does the inferior sagittal sinus
What does the thalamostriate vein and choroidal vein drain?
Thalamus and choroid plexus respectfully
What is the tentorial notch?
Opening between the free edge of the tentorium cerebelli and the clivus, allows for passage of brainstem
Describe the drainage of the cavernous sinus
It has three draigage routes;
- Superior petrosal sinus which drains to the sigmoid sinus,
- Inferior petrosal sinus to jugular bulb,
- Or via the venous plexus to the basilar plexus
What is a transtentorial herniation?
When there is an increase in intracranial pressure it causes herniation of brain through tentoiral notch. Can be life threatening
What produces cerebrospinal fluid?
Choroid plexuses
Label the following Diagram
Insert photo
Describe the formation of CSF
It is formed in the choroid plexus by epithelium cells which are differentiated from ependyma cells
How does CSF travel around the subarachnoid space and get reabsorbed?
CSF exits the ventriclar system into the subarachnoid space via apertures (paired lateral and single median) in the fourth ventricle through into the subarachnoid space around the brain. It gets reabsorbed by arachnoid granulations which then return the CSF back to the venous system via the superior sagittal sinus.
What is hydrocephalus?
The ventricular system becomes enlarged from either blocked transport of the CSF or from overproduction of CSF or blocked absorption. It causes an enlarged cranial cavity before sutures of the skull have fused and is treated with a shunt
