Ventricular System Overview:
The ventricles of the brain consist of the following: two lateral ventricles, a third ventricle, and a fourth ventricle.
Lateral Ventricles:
- Structure: Paired, C-shaped chambers located in each cerebral hemisphere.
- Location: Just below the corpus callosum.
Third Ventricle:
- Structure: A narrow, midline space between the left and right diencephalon.
- Connection: Communicates with the lateral ventricles through the interventricular foramen (foramen of Monro).
Cerebral Aqueduct:
- Other Names: Mesencephalic aqueduct or aqueduct of Sylvius.
- Location: Runs through the midbrain, connecting the third ventricle to the fourth ventricle.
Fourth Ventricle:
- Location: Between the pons and medulla anteriorly and the cerebellum posteriorly.
- Function: Communicates with the subarachnoid space through the median aperture (foramen of Magendie) and two lateral apertures (foramina of Luschka).
Cerebrospinal Fluid (CSF):
- Production: Produced by the choroid plexus located in each ventricle.
- Flow Path:
- From the lateral ventricles through the interventricular foramen into the third ventricle.
- Through the cerebral aqueduct into the fourth ventricle.
- From the fourth ventricle through the median and lateral apertures into the subarachnoid space, surrounding the brain and spinal cord.
- Drainage: CSF is reabsorbed into the bloodstream through arachnoid granulations, which drain into the superior sagittal sinus.
Functions of CSF:
- Buoyancy: Reduces the effective weight of the brain by 97-98%, allowing it to float within the skull.
- Cushioning: Protects the brain and spinal cord from trauma.
- Volume and Replacement: The total volume of CSF in adults is about 150 milliliters (less than half a can of soda), with a complete turnover approximately every eight hours, producing around 500 milliliters of CSF daily.
References
- Carpenter, M. B., & Sutin, J. (1983). Human Neuroanatomy. Williams & Wilkins.
- Haines, D. E. (2018). Fundamental Neuroscience for Basic and Clinical Applications (5th ed.). Elsevier.
- Hyman, B. T., & Tanzi, R. E. (2017). Cerebrospinal fluid. In G. W. Kreisel (Ed.), The Human Nervous System (3rd ed., pp. 565-578). Academic Press.
- Squire, L. R., Berg, D., Bloom, F. E., du Lac, S., Ghosh, A., & Spitzer, N. C. (2012). Fundamental Neuroscience (4th ed.). Elsevier.