Ventricular system
The ventricular system has been covered before and so we know there are 4 ventricles, or hollow spaces containing CSF, the liquid that nourishes and feeds the brain cells as well as remove wastes.
The fluid is filtered from blood by the choroid plexi and released to the ventricular system. The lateral ventricles are the first and then the csf moves to the third ventricle, then the cerebral canal and then the fourth ventricle.
From there it flows out of the 2 lateral apertures and median apertures. Then it flows around the brain and spinal cord to the sinuses and are drained.
After flowing out of the apertures it works its way around the outside of the brain, and there are subarachnoid cisterns, which are like spaces that contain relatively more csf, analogous to ventricles but smaller. The names of these are the: Cisterna magna, pontine cistern, interpeduncular cistern, and superior cistern.
choroid plexi
the inferior medullary velum has it but the superior does not.
Meninges
Anatomy of the meninges
This is content we have previously covered but is good to know again.
The meninges are a system of 3 layers which protects, supports, and nourishes the brain as well as allows csf fluid to flow around the brain and be drained.
The three layers each have a specialisation and are detailed below
Dura mater
This is the outermost layer and means tough mother. it has 2 layers, the meningeal and periosteal layers, which diverge at 3 large infoldings which extend down the transverse fissure, inbetween the cerebrum and cerebellum and the 2 hemispheres of the cerebellum.
These are called the falx cerebri, tentorium cerebelli and falx cerebelli. At the base (and inferior edge of the falx cerebri) of each of these foldings there are channels called sinuses and these allow the flow of circulated csf and venous blood ultimately into the internal jugular vein.
The arachnoid mater and pia mater both also fold down into these dural reflections.
Arachnoid mater
This is the middle most layer and its name and primary function is associated with the subarachnoid space, an unfilled areas surrounding the brain that the csf flows around as it passes to the sinuses it also is where blood vessels run as they go around the brain. Its name is from little projections down to the pia mater which have a structural role.
Pia mater
This is the layer closest to the brain and descends down with the sulci.