CSF CIRCULATION
CSF is produced mainly by choroid plexus of ventricles with small amount from extrachoroidal sources.
CSF is produced by the choroid plexus in 2 steps.plasma filtration and secretion of ions and water.CSF thus produced flows through foramen of monro into third ventricles.There small amount is added and then it flows through aqueduct of sylvius into fourth ventricle.CSF leaves fourth ventricle by 3 routes:foramen of Luscka,foramen of Magendie and small amount enters central canal of spinal cord. CSF enters cisterns through these foramens.These cisterns communicate with subarachnoid space around brain and spinal cord.Ultimately,CSF reaches arachnoid granulation by flowing upwards through subarachnoid space around cerebrum.It is then absorbed into venous sinuses.
