Cerebrospinal Fluid Overview and Pathway

Cerebrospinal fluid is critical for brain homeostasis, protection, and nutrient delivery.
It is secreted by the choroid plexus located in each lateral ventricle.

CSF flows through the interventricular foramina into the third ventricle.
The choroid plexus in the third ventricle contributes additional CSF.
From the third ventricle, CSF travels down the cerebral aqueduct to reach the fourth ventricle.
The fourth ventricle's choroid plexus further increases CSF production.
CSF exits the fourth ventricle through two lateral apertures and one median aperture.

CSF fills the subarachnoid space, surrounding the brain and spinal cord, providing cushioning and support.
Arachnoid villi are specialized structures where CSF is reabsorbed into venous blood in dural venous sinuses.
The subarachnoid space lies between the arachnoid mater and pia mater, holding the CSF.

The dura mater is the outermost layer of the meninges, providing protective covering for the CNS.
The choroid plexus is a highly vascular structure lining the ventricles, essential for CSF secretion.
The third ventricle is centrally located in the diencephalon, serving as a critical processing center.
The cerebral aqueduct, a narrow channel, connects the third and fourth ventricles, facilitating CSF flow between them.
The fourth ventricle is situated between the cerebellum and the pons, playing a key role in the flow of CSF towards the central nervous system.

Lateral apertures and the median aperture serve as conduits for CSF to flow from the ventricular system into the subarachnoid space.
The median aperture specifically drains CSF from the fourth ventricle into the cisterna magna, an expanded area in the subarachnoid space.