Cerebrospinal fluid (CSF), Liquor cerebrospinalis, is a clear bodily fluid that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord. In essence, the brain "floats" in it.
The CSF occupies the space between the arachnoid mater (the middle layer of the brain cover, meninges), and the pia mater (the layer of the meninges closest to the brain). It constitutes the content of all intra-cerebral (inside the brain, cerebrum) ventricles, cisterns, and sulci (singular sulcus), as well as the central canal of the spinal cord.
It acts as a "cushion" or buffer for the cortex, providing a basic mechanical and immunological protection to the brain inside the skull.
It is produced in the choroid plexus.
CSF is produced in the brain by modified ependymal cells in the choroid plexus (approx. 50-70%), and the remainder is formed around blood vessels and along ventricular walls. It circulates from the lateral ventricles to the foramen of Monro (Interventricular foramen), third ventricle, aqueduct of Sylvius (Cerebral aqueduct), fourth ventricle, foramina of Magendie (Median aperture) and foramina of Luschka (Lateral apertures); subarachnoid space over brain and spinal cord; reabsorption into venous sinus blood via arachnoid granulations.
It had been thought that CSF returns to the vascular system by entering the dural venous sinuses via the arachnoid granulations (or villi). However, some have suggested that CSF flow along the cranial nerves and spinal nerve roots allow it into the lymphatic channels; this flow may play a substantial role in CSF reabsorbtion, in particular in the neonate, in which arachnoid granulations are sparsely distributed. The flow of CSF to the nasal submucosal lymphatic channels through the cribriform plate seems to be specially important.
Full article ▸