Which structure absorbs CSF into the venous system?

Which structure absorbs CSF into the venous system?

• A. Arachnoid granulations
• B. Choroid plexus
• C. Ependymal lining
• D. Pia mater

Answer: (A)

CSF is absorbed into the venous system by arachnoid granulations. These extensions of the arachnoid membrane protrude into the dural venous sinuses and act as one-way drainage pathways, letting CSF flow into the venous blood when CSF pressure exceeds venous pressure. The primary site is the superior sagittal sinus, with other sinuses involved as well. The choroid plexus, on the other hand, produces CSF, not absorbs it. The ependymal lining lines the ventricles and helps move CSF, but it is not the absorption route. The pia mater is the innermost meningeal layer and does not participate in CSF absorption. Blockage or dysfunction of arachnoid granulations can lead to accumulation of CSF and hydrocephalus.

CSF is absorbed into the venous system by arachnoid granulations. These extensions of the arachnoid membrane protrude into the dural venous sinuses and act as one-way drainage pathways, letting CSF flow into the venous blood when CSF pressure exceeds venous pressure. The primary site is the superior sagittal sinus, with other sinuses involved as well. The choroid plexus, on the other hand, produces CSF, not absorbs it. The ependymal lining lines the ventricles and helps move CSF, but it is not the absorption route. The pia mater is the innermost meningeal layer and does not participate in CSF absorption. Blockage or dysfunction of arachnoid granulations can lead to accumulation of CSF and hydrocephalus.