After leaving the third ventricle. CSF travels directly to the subarachnoid space. True False
The correct answer and explanation is:
The correct answer is False.
Cerebrospinal fluid (CSF) does not directly travel from the third ventricle to the subarachnoid space. After being produced in the choroid plexus of the ventricles, CSF flows through a series of pathways. Here’s the sequence of events:
- From the Third Ventricle to the Aqueduct of Sylvius (Cerebral Aqueduct): After CSF is produced in the lateral ventricles, it flows into the third ventricle. From the third ventricle, CSF travels through the aqueduct of Sylvius (also called the cerebral aqueduct) to reach the fourth ventricle.
- From the Fourth Ventricle to the Subarachnoid Space: From the fourth ventricle, CSF enters the subarachnoid space of the brain and spinal cord through three openings:
- Median aperture (foramen of Magendie): This opening allows CSF to enter the subarachnoid space around the brain.
- Lateral apertures (foramina of Luschka): These openings allow CSF to flow into the subarachnoid space around the brain and spinal cord.
- Circulation in the Subarachnoid Space: Once in the subarachnoid space, CSF circulates around the brain and spinal cord, providing cushioning, nutrient delivery, and waste removal.
- Absorption of CSF: Finally, CSF is absorbed into the venous blood through structures called arachnoid villi, which are located in the dural sinuses.
Therefore, the CSF travels from the third ventricle to the fourth ventricle and then enters the subarachnoid space, not directly from the third ventricle to the subarachnoid space.