The mesencephalic duct, also known as the aqueductus mesencephali, aqueduct of Sylvius

Franciscus Sylvius

Franciscus Sylvius , born Franz de le Boë, was a Dutch physician and scientist who was an early champion of Descartes', Van Helmont's and William Harvey's work and theories...

or the cerebral aqueduct, contains cerebrospinal fluid

Cerebrospinal fluid

Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...

 (CSF), is within the mesencephalon

Mesencephalon

The midbrain or mesencephalon is a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal , and temperature regulation....

 (or midbrain) and connects the third ventricle

Third ventricle

The third ventricle is one of four connected fluid-filled cavities comprising the ventricular system within the human brain. It is a median cleft between the two thalami, and is filled with cerebrospinal fluid ....

 in the diencephalon

Diencephalon

The diencephalon is the region of the vertebrate neural tube which gives rise to posterior forebrain structures. In development, the forebrain develops from the prosencephalon, the most anterior vesicle of the neural tube which later forms both the diencephalon and the...

 to the fourth ventricle

Fourth ventricle

The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ventricle...

 in the mesencephalon

Mesencephalon

The midbrain or mesencephalon is a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal , and temperature regulation....

, which is between the pons

Pons

The pons is a structure located on the brain stem, named after the Latin word for "bridge" or the 16th-century Italian anatomist and surgeon Costanzo Varolio . It is superior to the medulla oblongata, inferior to the midbrain, and ventral to the cerebellum. In humans and other bipeds this means it...

 and cerebellum

Cerebellum

The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...

.

Development

The cerebral aqueduct, similarly to other parts of the ventricular system of the brain, develops from the central canal of the neural tube. Specifically, the duct originates from the portion of the neural tube that is present in the developing mesencephalon, hence the name "mesencephalic duct."