Median aperture | |
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Details | |
Identifiers | |
Latin | apertura mediana |
NeuroNames | 641 |
TA98 | A14.1.05.722 |
TA2 | 5970 |
FMA | 75015 |
Anatomical terms of neuroanatomy |
The median aperture (median aperture of fourth ventricle or foramen of Magendie) is an opening at the caudal portion of the roof of the fourth ventricle.[1] It allows the flow of cerebrospinal fluid (CSF) from the fourth ventricle into the cisterna magna.[2][3] The other openings of the fourth ventricle are the lateral apertures - one on either side.[4] The median aperture varies in size but accounts for most of the outflow of CSF from the fourth ventricle. [1]
The choroid plexuses are highly vascular structures that project into each of the ventricles and continuously produce cerebrospinal fluid by active secretion from the blood. CSF escapes from the fourth ventricle (to the subarachnoid space) via three openings: the single median aperture and the two lateral apertures. It is ultimately reabsorbed into the venous system via the arachnoid granulations which run along the superior aspect of the cerebral hemispheres ... correspond to the arachnoid villi, finger-like projections into a large venous channel called the superior sagittal sinus.
CSF is produced by the choroid plexuses of the lateral, third, and fourth ventricle. The production of CSF is not pressure regulated, and it continues to be produced even if the reabsorption mechanisms are obstructed. The circulation of CSF is as follows: Lateral ventricle → interventricular foramen of Monroe → third ventricle → aqueduct of sylvius → fourth ventricle → foramen of Magendie (median aperture)/foramen of Luschka (lateral aperture) → subarachnoid space.
Ciolkowski
was invoked but never defined (see the help page).