Cerebrospinal fluid (CSF) is primarily removed by bulk reabsorption into the bloodstream via arachnoid villi and by clearance to peripheral lymphatic vessels accessed along cranial nerve sheathes.
Mechanisms of CSF Removal
The removal of CSF is crucial for maintaining intracranial pressure and a stable brain environment. The two primary mechanisms involved are:
- Arachnoid Villi Reabsorption: Classically, CSF is reabsorbed into the venous sinuses of the brain through specialized structures called arachnoid villi (or granulations). These villi act as one-way valves, allowing CSF to flow into the blood but preventing blood from entering the CSF. This is the major route of CSF removal.
- Lymphatic Drainage: CSF can also be cleared via peripheral lymphatic vessels. This clearance occurs along the cranial nerve sheathes, providing an alternative pathway for CSF to exit the cranial cavity.
In summary, CSF removal is achieved through the combination of reabsorption into the bloodstream via arachnoid villi and drainage into peripheral lymphatic vessels.
