Cerebral Ventricles

Background

• Embryology: the cavity of the neural tube persists as the cerebral ventricles
• Lined by a single epithelial layer: ependyma
• The ependyma form the choroidal plexus along with the pia mater
• Choroidal plexus: 70% of CSF production (the other 30% from other brain capillaries)
• Normal CSF volume is 130ml
• Normal ICP is 5-15 mmHg (about 10-20 cm of water)

• Normal CSF production is 550ml/day: note that this means the CSF turns over approximately 4 times per day

Lateral ventricles

• These are the largest chambers of the ventricular system
• Lie within each cerebral hemisphere
• C-shaped
• The caudate nucleus sits in the concavity of the lateral ventricle
• Communicate with the third ventricle via the foramina of Munro

Third ventricle

• Within the diencephalon
• The thalamus lies next to the lateral wall of the third ventricle
• The floor of the third ventricle if formed by the hypothalamus
• Communicates with the fourth ventricle via the cerebral aqueduct

Fourth ventricle

• Lies within the pons and upper medulla
• The floor of the fourth ventricle is close to various cranial nerve nuclei
• Communicates with the cerebellomedullary cistern via the foreman of Magendie
• Communicates with the pontine cistern via the lateral foramina of Luschka