Ventricular system

Last revised by Sajanakan Sriselvakumar on 3 Aug 2023

The ventricular system in the brain is a series of interconnecting spaces and channels within the brain composed of cerebrospinal fluid (CSF). CSF is produced by ependymal cells which line the ventricles. They are continuous with the central canal. Ventricles contain around 20% of the total average adult CSF volume, around 20-25 mL.

The ventricular system consists of:

The interconnections between the ventricles occur through the following:

Both the cisterna magna and the cerebellopontine cistern are in the subarachnoid space. This space is continuous with the subarachnoid space around the cord down to the level of the cauda equina.

Major CSF production comes from choroid plexus found in the lateral, third and fourth ventricles of the brain which are highly vascularized epithelial tissue masses 3. Notably, choroid plexus is not found in the frontal or occipital horns of lateral ventricles, nor in the cerebral aqueduct.


A single cavity, or hollow of the neural tube, serves as the foundation for the ventricular system. Around the fourth week of gestation, the neural tube begins to develop. The neural cavity and amniotic cavity are then separable after the spinal neurocele closes.

From the cephalic to the caudal end, three dilatations are formed: the prosencephalon (forebrain), mesencephalon (midbrain), and rhombencephalon (hindbrain). 

  • lateral ventricles develop from the telencephalic cavity.

  • third ventricle develops from the diencephalic cavity.

  • cerebral aqueduct develops from the restricted mesencephalic cavity, while the fourth ventricle is formed from the rhombencephalic cavity.

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Cases and figures

  • Figure 1
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  • Figure 2: ventricles superimposed on brain
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  • Figure 3: coronal brain through 3rd ventricle
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  • Figure 4: brain (sagittal section)
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  • Figure 5: directional CSF flow
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