1.1.4 CSF Flashcards
Why is the brain hollow?
Develops from the neural tube which is hollow
What are cavities in the brain called?
Ventricles
What do ventricles contain?
Choroid plexus
How much CSF do choroid plexi produce each day?
600-700ml of CSF
What is the function of CSF?
Metabolic and mechanical functions
How does CSF circulate after being produced?
Circulates through ventricular system and subarachnoid space before being reabsorbed at the arachnoid granulations
What are arachnoid granulations?
Evaginations of arachnoid into dural venous sinuses, most prominent in the superior sagital dural venous sinus
Where do the two lateral ventricles connect?
Interventricular foramen
How does CSF drain?
Lateral ventricles connect and interventricular foramen
CSF drains into the 3rd ventricle
Drains into the aqueduct of midbrain
Drains into the 4th ventricle
Drains into the central canal (very small wouldnt be enough to drain 700 ml of CSF), median and 2 lateral apetures
Subarachnoid space
What does the fourth ventricle contain?
1 median and 2 lateral apetures
Why can a dural tear cause headaches when standing up?
CSF cushions the brain, if there is a dural tear CSF can leak out and there can be an inadequate volume of CSF
When standing up there is a low CSF pressure causing the brain to sag and pull on the meninges causing a headache
How do you treat dural tears that leak CSF?
Inject blood by a lumbar puncture, blood will clott and form a scab at the site of the tear plugging the hole
What happens in a ventricular blockage?
CSF unable to drain which causes the supplying ventricles to become enlarged which can compress local structures
What area of the ventricular system is most commonly blocked?
Aqueduct of midbrain due to tumours or stenosis
What can be a complication of a subarachnoid haemorrhage?
Arachnoid granulations can become blocked, CSF unable to drain, causing CSF accumulation leading to a raised intracranial pressure
