Cerebrospinal fluid

The cerebrospinal fluid (CSF) ^{[3, 5, 50, 71, 91]}, is the liquid that bathes the central nervous system ^{[45, 67]} (brain and spinal cord). It thus provides protection against mechanical shocks and vibrations ^{[5, 31, 42, 68]}; it plays a very important role in the regulation of intracranial pressure ^{[42, 69]}, it participates in cerebral metabolic processes by regulating the exchange of substances ^[42] , and performs many other functions as well ^[160].

The CSF circulates in two different compartments: an intra-encephalic compartment consisting of ependymal cavities or ventricles, and an extra-encephalic compartment corresponding to the subarachnoid spaces.

The CSF is secreted at the level of the choroid plexuses ^[38] : clusters of capillary blood vessels located within the ventricular system ^[41].

This system, which hollows out the brain, consists of four large cavities ^[70] (the cerebral ventricles ^[37]) connected to one another by channels. It continues in the spinal cord as the central canal ^[42].

There are two lateral ventricles ^{[43, 66]}, each occupying the center of a cerebral hemisphere. These two lateral ventricles are each connected to the third ventricle ^{[38, 224]} at the core of the diencephalon via the two interventricular foramina (foramina of Monro) ^{[2, 41, 71, 160]}.

The third ventricle is connected to the fourth ventricle ^{[43, 51]} at the level of the brainstem by the aqueduct of Sylvius ^{[41, 43, 72]}. From there, the CSF exits through the median aperture (foramen of Magendie) ^{[32, 38]} to occupy the subarachnoid spaces ^{[43, 64, 230]} between the pia mater ^{[38, 85]} and the arachnoid ^{[64, 94]}.

The CSF is then reabsorbed at the top of the skull through the arachnoid granulations (Pacchionian granulations) ^{[160, 183, 226]}.