Cerebral aqueduct

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Cerebral aqueduct
Cn3nucleus-en.svg
Section through superior colliculus showing path of oculomotor nerve.
Gray736.png
Drawing of a cast of the ventricular cavities, viewed from the side.
Details
Part of Ventricular system
Identifiers
Latin aqueductus mesencephali (cerebri)
aqueductus Sylvii
MeSH D002535
NeuroNames 509
NeuroLex ID birnlex_1261
TA98 A14.1.06.501
TA2 5910
FMA 78467
Anatomical terms of neuroanatomy

The cerebral aqueduct (aqueduct of the midbrain, aqueduct of Sylvius, Sylvian aqueduct, mesencephalic duct) is a small, narrow tube connecting the third and fourth ventricles of the brain. [1] [2] The cerebral aqueduct is a midline structure that passes through the midbrain. It extends rostrocaudally through the entirety of the more posterior part of the midbrain. It is surrounded by the periaqueductal gray (central gray), a layer of gray matter. [3]

Contents

Congenital stenosis of the cerebral aqueduct is a cause of congenital hydrocephalus. [3]

It is named for Franciscus Sylvius.

Anatomy

The cerebral aqueduct is roughly circular in transverse section, and measures 1-2 mm in diameter. [3] It is 15 mm long and is commonly subdivided into a pars anterior antrum, and pars posterior. [2]

Relations

Rostrally, it is continuous with the third ventricle, commencing just inferior to the posterior commissure. [3]

Caudally, it is continuous with the fourth ventricle at the junction of the mesencephalon and pons. [3]

The midbrain tegmentum is situated anteriorly to the cerebral aqueduct. [3] The portion of the tegmentum posterior to the aqueduct is the tectum. [1] The superior and inferior colliculi that make up the corpora quadrigemina are situated posteriorly to it. [3]

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 that is present in the developing mesencephalon, hence the name "mesencephalic duct." [4]

Function

The cerebral aqueduct acts like a canal that passes through the midbrain. It connects the third ventricle with the fourth ventricle so that cerebrospinal fluid (CSF) moves between the cerebral ventricles and the canal connecting these ventricles. [5]

Clinical significance

Aqueductal stenosis, a narrowing of the cerebral aqueduct, obstructs the flow of CSF and has been associated with non-communicating hydrocephalus. Such narrowing can be congenital, arise via tumor compression (e.g. pinealoblastoma), or through cyclical gliosis secondary to an initial partial obstruction. [5]

History

The cerebral aqueduct was first named after Franciscus Sylvius. [6]

Additional images

See also

Related Research Articles

<span class="mw-page-title-main">Hydrocephalus</span> Abnormal increase in cerebrospinal fluid in the ventricles of the brain

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 incontinence, personality changes, or mental impairment. In babies, it may be seen as a rapid increase in head size. Other symptoms may include vomiting, sleepiness, seizures, and downward pointing of the eyes.

<span class="mw-page-title-main">Brainstem</span> Posterior part of the brain, adjoining and structurally continuous

The brainstem is the stalk-like part of the brain that connects the forebrain with the spinal cord. In the human brain, the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is continuous with the thalamus of the diencephalon through the tentorial notch.

<span class="mw-page-title-main">Ventricular system</span> Structures containing cerebrospinal fluid

In neuroanatomy, 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 continuous with the central canal of the spinal cord from the fourth ventricle, allowing for the flow of CSF to circulate.

<span class="mw-page-title-main">Third ventricle</span> Ventricle of the brain located between the two thalami

The third ventricle is one of the four connected cerebral 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 ventricles, and is filled with cerebrospinal fluid (CSF).

<span class="mw-page-title-main">Midbrain</span> Forward-most portion of the brainstem

The midbrain or mesencephalon is the rostral-most portion of the brainstem connecting the diencephalon and cerebrum with the pons. It consists of the cerebral peduncles, tegmentum, and tectum.

<span class="mw-page-title-main">Oculomotor nucleus</span>

The fibers of the oculomotor nerve arise from a nucleus in the midbrain, which lies in the gray substance of the floor of the cerebral aqueduct and extends in front of the aqueduct for a short distance into the floor of the third ventricle. From this nucleus the fibers pass forward through the tegmentum, the red nucleus, and the medial part of the substantia nigra, forming a series of curves with a lateral convexity, and emerge from the oculomotor sulcus on the medial side of the cerebral peduncle.

<span class="mw-page-title-main">Midbrain tegmentum</span>

The midbrain is anatomically delineated into the tectum (roof) and the tegmentum (floor). The midbrain tegmentum extends from the substantia nigra to the cerebral aqueduct in a horizontal section of the midbrain. It forms the floor of the midbrain that surrounds below the cerebral aqueduct as well as the floor of the fourth ventricle while the midbrain tectum forms the roof of the fourth ventricle. The tegmentum contains a collection of tracts and nuclei with movement-related, species-specific, and pain-perception functions. The general structures of midbrain tegmentum include red nucleus and the periaqueductal grey matter.

<span class="mw-page-title-main">Lateral sulcus</span> Crevice in the brain separating the frontal and parietal lobes from the temporal

In neuroanatomy, the lateral sulcus is one of the most prominent features of the human brain. The lateral sulcus is a deep fissure in each hemisphere that separates the frontal and parietal lobes from the temporal lobe. The insular cortex lies deep within the lateral sulcus.

<span class="mw-page-title-main">Fourth ventricle</span> One of four central brain cavities filled with cerebrospinal fluid

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. The fourth ventricle extends from the cerebral aqueduct to the obex, and is filled with cerebrospinal fluid (CSF).

<span class="mw-page-title-main">Inferior colliculus</span> Midbrain structure involved in the auditory pathway

The inferior colliculus (IC) is the principal midbrain nucleus of the auditory pathway and receives input from several peripheral brainstem nuclei in the auditory pathway, as well as inputs from the auditory cortex. The inferior colliculus has three subdivisions: the central nucleus, a dorsal cortex by which it is surrounded, and an external cortex which is located laterally. Its bimodal neurons are implicated in auditory-somatosensory interaction, receiving projections from somatosensory nuclei. This multisensory integration may underlie a filtering of self-effected sounds from vocalization, chewing, or respiration activities.

<span class="mw-page-title-main">Median aperture</span>

The median aperture is an opening of the fourth ventricle at the caudal portion of the roof of the fourth ventricle. It allows flow of cerebrospinal fluid (CSF) from the fourth ventricle into the cisterna magna. The other two openings of the fourth ventricle are the lateral apertures - one on either side. Nonetheless, the median aperture accounts for most of the outflow of CSF out of the fourth ventricle. The median aperture varies in size.

<span class="mw-page-title-main">Periaqueductal gray</span> Nucleus surrounding the cerebral aqueduct

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 descending pain modulation. It has enkephalin-producing cells that suppress pain.

<span class="mw-page-title-main">Corpora quadrigemina</span> Part of the brain

In the brain, the corpora quadrigemina are the four colliculi—two inferior, two superior—located on the tectum of the dorsal aspect of the midbrain. They are respectively named the inferior and superior colliculus.

<span class="mw-page-title-main">Dandy–Walker malformation</span> Congenital malformation of the cerebellar vermis

Dandy–Walker malformation (DWM), also known as Dandy–Walker syndrome (DWS), is a rare congenital brain malformation in which the part joining the two hemispheres of the cerebellum does not fully form, and the fourth ventricle and space behind the cerebellum are enlarged with cerebrospinal fluid. Most of those affected develop hydrocephalus within the first year of life, which can present as increasing head size, vomiting, excessive sleepiness, irritability, downward deviation of the eyes and seizures. Other, less common symptoms are generally associated with comorbid genetic conditions and can include congenital heart defects, eye abnormalities, intellectual disability, congenital tumours, other brain defects such as agenesis of the corpus callosum, skeletal abnormalities, an occipital encephalocele or underdeveloped genitalia or kidneys. It is sometimes discovered in adolescents or adults due to mental health problems.

<span class="mw-page-title-main">Trochlear nucleus</span> Motor nucleus of cranial nerve IV

The nucleus of the trochlear nerve is a motor nucleus in the medial midbrain giving rise to the trochlear nerve.

<span class="mw-page-title-main">Superior cerebellar peduncle</span>

In the human brain, the superior cerebellar peduncle is a paired structure of white matter that connects the cerebellum to the midbrain. It consists mainly of efferent fibers, the cerebellothalamic tract that runs from a cerebellar hemisphere to the contralateral thalamus, and the cerebellorubral tract that runs from a cerebellar hemisphere to the red nucleus. It also contains afferent tracts, most prominent of which is the ventral spinocerebellar tract. Other afferent tracts are the trigeminothalamic fibers, tectocerebellar fibers, and noradrenergic fibers from the locus coeruleus. The superior peduncle emerges from the upper and medial parts of the white matter of each hemisphere and is placed under cover of the upper part of the cerebellum.

<span class="mw-page-title-main">Superior medullary velum</span> Thin layer between the superior cerebellar peduncles

The superior medullary velum is a thin, transparent lamina of white matter which - together with the inferior medullary velum - forms the roof of the fourth ventricle. It extends between the two superior cerebellar peduncles. The lingula of cerebellum covers - and adheres to - its dorsal surface.

<span class="mw-page-title-main">Posteromedial central arteries</span>

The posteromedial central arteries or paramedian arteries (also are branches of the posterior cerebral artery, and posterior communicating artery. They entering the substance of the brain through the posterior perforated substance. They supply a large portion of the diencephalon as well as some subcortical telencephalic structures.

<span class="mw-page-title-main">Aqueductal stenosis</span> Narrowing of the aqueduct of Sylvius

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 obstructive hydrocephalus.

References

  1. 1 2 Sinnatamby, Chummy S. (2011). Last's Anatomy (12th ed.). p. 476. ISBN   978-0-7295-3752-0.
  2. 1 2 Rubino, Jessica M.; Hogg, Jeffery P. (2024), "Neuroanatomy, Cerebral Aqueduct (Sylvian)", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID   31082032 , retrieved 2024-07-02
  3. 1 2 3 4 5 6 7 Standring, Susan (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42th ed.). New York: Elsevier. p. 409. ISBN   978-0-7020-7707-4. OCLC   1201341621.
  4. Le, Tao; Bhushan, Vikas; Vasan, Neil (2010). First Aid for the USMLE Step 1: 2010 20th Anniversary Edition. USA: The McGraw-Hill Companies, Inc. pp.  126. ISBN   978-0-07-163340-6.
  5. 1 2 Rubino, Jessica; Hogg, Jeffery (31 July 2020). Neuroanatomy, cerebral aqueduct (Sylvian). Treasure Island, FL: StatPearls Publishing.
  6. Kompanje, Erwin J. O. (1 January 2005). "An historical homage from Denmark: the aqueduct of Sylvius". Neurosurgical Review. 28 (1): 77–78. doi:10.1007/s10143-004-0361-6. ISSN   1437-2320.