Ventricular system

The ventricular system is a set of structures containing cerebrospinal fluid in the brain. It is continuous with the central canal of the spinal cord. The system comprises four ventricles:

• right and left lateral ventricles
• third ventricle
• fourth ventricle

This is shown in the diagram below [source Wikipedia].

Three-dimensional representation of the ventricular system of the human brain. The lateral ventricles in red, the third and fourth ventricle are the upper and lower blue mass respectively.

The structures of the ventricular system are embryologically derived from the centre of the neural tube (the neural canal). As the part of the primitive neural tube that will become the brain stem develops, the neural canal expands dorsally and laterally, creating the fourth ventricle, whereas the neural canal that does not expand and remains the same at the level of the midbrain superior to the fourth ventricle forms the cerebral aqueduct. Likewise, the neural canal in the spinal cord that does not change forms the central canal.