Meninges, venous drainage of the brain and CSF Flashcards
What mater dips into the crevices of the brain?
Only pia
what are cerebral arteries embedded in?
Pia mater
What mater acts as a sealed bag for CSF?
Arachnoid mater
What are arachnoid trabeculae?
Extentions of arachnoid mater to the pia mater which help to keep the brain suspended in place.
What mater are the branches of the middle meningeal artery carried in and supply?
Dura
What are cisterns?
Spaces filled with CSF
Where is the interpeduncular cistern found?
In between the 2 cerebral peduncles of the midbrain
Where is the cisterna pontis found?
Just caudal to the buldge of the pons
Where is the superior cistern found?
- Dorsal to midbrain and superior and inferior colliculi
Where is the cisterna magna (cerebellomedullaris) found?
- Posterior to cerebellum and in posterior fossa of the brain
What is the clinical significance of the cisterna magna?
One of the places where CSF can be taken from if spinal cord cannot be reached - can cause subarachnoid haemorrhage
Where do berry aneurysms occur?
- Arterial circle of Willis which lies in subarachnoid space
- Frequent site is where posterior communicating artery arises from the Internal carotid artery
What are the ‘tooth-like’ connective tissues of pia mater which attach to the dura mater called?
Denticulate ligaments
At what level does a lumbar puncture usually take place?
- Below L2
- Usually L4/5
Where do the veins of the brain lie?
Subarachnoid space
What do the veins of the brain drain into?
Cranial venous sinuses
How are venous sinuses arranged?
Along the borders of folds of dura (falx cerebri,
What is the tentorium cerebelli?
Compartmentalises the brain into cerebrum (occipital lobes) and cerebellum (tent like structure of dura)
What is the sinus called that follow the falx cerebri?
The superior sagittal sinus
Where does the transverse sinus lie?
On the border of the tentorium cerebelli
What are the main sinuses which drain into the confluence of sinuses?
- Superior sagittal sinus
- Transverse sinus
- Straight sinus
What veins drain into the straight sinus?
- Inferior sagittal sinus
- Great cerebral vein of galen
What is the tentorial notch?
- Anterior opening between the free edge of the cerebellar tentorium and the clivus for the passage of the brainstem
- Midbrain continues with the thalamus of the diencephalon through the tentorial notch
What is a trans-tentorial herniation?
- Increase in intracranial pressure can cause part of brain (temporal lobe) to be pulled down into tentorial notch
What is the clinical significant of the cavernous sinus?
Thrombus can get caught here - abducens and carotid artery lie beside as well as sympathetic plexus, oculomotor, trochlear, V1 and 2 of trigeminal
What can cavernous sinuses receive infection from?
- Opthalmic or facial veins can cause thrombus
Veins bridgining into sinuses can become fragile in what diseases?
- Where the brain is atrophied (e.g alcoholism)
- Can cause subdural haemorrhage
How much CSF is in the brain?
150ml produced at 0.5ml/min and turns over 4 times a day
- 500ml per day
What is the grey matter right next to the lateral ventricles called?
Caudate nucleus
Where is the CSF found - how is it divided?
- 75 ml in cisterns
- 50 ml in subarach. space
- 25 ml in ventricles
What is the choroid plexus?
Coreof vascular tissue (in pia) covered by an epithelium which secretes cerebrspinal fluid
- Epithelium differentiated from ependyma - classified as glial
Where is CSF created?
- Formed in choroid plexus (in ventricles) (up to half from blood vessels surrounding the ventricles)
How does CSF flow out from the ventricles?
Flows out of ventricle system into subarachnoid space via apertures in 4th ventricle
What are the apertures called by which CSF flows out to reach the subarachnoid space?
- Paired lateral apertures (Luschka)
- Single median (Magendie)
What sinus does the CSF specifically drain into?
Superior sagittal via arachnoid granulations
How is hydrocephalus treated?
Shunt from frontal horn of LVs to abdominal cavity (some cases the heart)
What are the 2 main types of hydrocephalus?
- Communicative - overproduction / blocked absorption of CSF
- Non-communicative - due to blocked transport
