The cerebral aqueduct (aqueductus mesencephali, mesencephalic duct, sylvian aqueduct or aqueduct of Sylvius) is a conduit for

cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the ...

(CSF) that connects the

third ventricle The third ventricle is one of the four connected ventricles of the ventricular system within the mammalian brain. It is a slit-like cavity formed in the diencephalon between the two thalami, in the midline between the right and left lateral ...

to the

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 ve ...

of the

ventricular system The ventricular system is a set of four interconnected cavities known as cerebral ventricles in the brain. Within each ventricle is a region of choroid plexus which produces the circulating cerebrospinal fluid (CSF). The ventricular system is co ...

of the brain. It is located in the

midbrain The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal (alertness), and temperature regulation. The name comes from the Greek ''mesos'', " ...

dorsal to the

pons The pons (from Latin , "bridge") is part of the brainstem that in humans and other bipeds lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum. The pons is also called the pons Varolii ("bridge of Va ...

and ventral to the cerebellum. The cerebral aqueduct is surrounded by an enclosing area of

gray matter Grey matter is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil (dendrites and unmyelinated axons), glial cells (astrocytes and oligodendrocytes), synapses, and capillaries. Grey matter is distingui ...

called the

periaqueductal gray The periaqueductal gray (PAG, also known as the central gray) is a brain region that plays a critical role in autonomic function, motivated behavior and behavioural responses to threatening stimuli. PAG is also the primary control center for d ...

, or central gray. It was first named after

Franciscus Sylvius Franciscus Sylvius (15 March 1614 – 19 November 1672), born Franz de le Boë, was a Dutch physician and scientist (chemist, physiologist and anatomist) who was an early champion of Descartes', Van Helmont's and William Harvey's work and ...

Structure

Development

The cerebral aqueduct, as other parts of the ventricular system of the brain, develops from the central canal of the neural tube, and it originates from the portion of the

neural tube In the developing chordate (including vertebrates), the neural tube is the embryonic precursor to the central nervous system, which is made up of the brain and spinal cord. The neural groove gradually deepens as the neural fold become elevated, ...

that is present in the developing mesencephalon, hence the name "mesencephalic duct."

Function

The cerebral aqueduct acts like a canal that passes through the

. It connects the

with the

so that

(CSF) moves between the cerebral ventricles and the canal connecting these ventricles.

Clinical significance

Aqueductal stenosis Aqueductal stenosis is a narrowing of the aqueduct of Sylvius which blocks the flow of cerebrospinal fluid (CSF) in the ventricular system. Blockage of the aqueduct can lead to hydrocephalus, specifically as a common cause of congenital and/or ob ...

, a narrowing of the cerebral aqueduct, obstructs the flow of CSF and has been associated with

non-communicating hydrocephalus Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. This typically causes increased pressure inside the skull. Older people may have headaches, double vision, poor balance, urinary inco ...

. Such narrowing can be congenital, arise via

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

compression (e.g.

pinealoblastoma Pineoblastoma is a malignant tumor of the pineal gland. A pineoblastoma is a supratentorial midline primitive neuroectodermal tumor. Pineoblastoma can present at any age, but is most common in young children. They account for 0.001% of all primary ...

), or through cyclical

gliosis Gliosis is a nonspecific reactive change of glial cells in response to damage to the central nervous system (CNS). In most cases, gliosis involves the proliferation or hypertrophy of several different types of glial cells, including astrocytes, ...

secondary to an initial partial obstruction.

History

The cerebral aqueduct was first named after

Additional images

File:Gray710.png, Transverse section through

mid-brain The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal (alertness), and temperature regulation. The name comes from the Greek ''mesos'', "m ...

; number 2 indicates the cerebral aqueduct. File:Gray711.png, Transverse section of mid-brain at level of inferior colliculi. File:Gray712.png, Transverse section of mid-brain at level of superior colliculi. File:Periaqueductal_MRI.PNG, MRI section of mid-brain. File:Gray720.png, Median sagittal section of brain. File:Gray734.png, Scheme showing relations of the ventricles to the surface of the brain. File:Slide1qq.JPG, Cerebral aqueduct File:Slide7qq.JPG, Cerebral aqueduct File:Slide2HOM.JPG, Cerebral peduncle, optic chasm, cerebral aqueduct. Inferior view. Deep dissection. File:Slide3HOM.JPG, Cerebral peduncle, optic chasm, cerebral aqueduct. Inferior view. Deep dissection. File:Slide2ERV.JPG, Cerebrum. Inferior view.Deep dissection

References

External links

* {{Authority control Ventricular system