- Arachnoid mater
Infobox Brain
Name = PAGENAME
Latin =
GraySubject = 193
GrayPage = 876
Caption = Themedulla spinalis and its membranes.
Caption2 = Diagrammatic representation of a section across the top of theskull , showing the membranes of the brain, etc.
IsPartOf =Meninges
Components =
Artery =
Vein =
BrainInfoType = ancil
BrainInfoNumber = 561
MeshName = Arachnoid
MeshNumber = A08.186.566.166
DorlandsPre = a_56
DorlandsSuf = 12149123
The arachnoid mater is one of the threemeninges , the membranes that cover thebrain andspinal cord . It is interposed between the two other meninges, the more superficialdura mater and the deeperpia mater , and is separated from the pia mater by thesubarachnoid space .The delicate, spiderweb-like (therefore the name) arachnoid layer, attached to the inside of the dura, surrounds the brain and spinal cord but does not line the brain down into its sulci (folds).
Cerebrospinal fluid flows under this membrane in the subarachnoid space, which is full of the delicate fibres of the arachnoid extending down to attach to the pia mater.The portions covering the
brain andspinal cord are called "arachnoidea encephali" and "arachnoidea spinalis", respectively.The arachnoid and pia mater are sometimes considered as a single structure, the "leptomeninx", or the plural version, "leptomeninges". (Lepto- from the root meaning "thin" in Greek). Similarly, the dura in this situation is called the "pachymeninx".
Etymology
"Arachnoid" is from a Greek root, and means "cob web like". The "mater" designation (meaning "mother" in Latin) is borrowed from the "dura mater" and "pia mater", which were Latin translations of Arabic terms. While "mater" does not technically belong with the arachnoid layer, it has nevertheless been adopted by it for uniformity with the other meninges, and "arachnoid mater" is currently the
Terminologia Anatomica international standard.
=AdditionalReferences
* Orlando Regional Healthcare, Education and Development. 2004. [http://www.orlandoregional.org/pdf%20folder/overview%20adult%20brain%20injury.pdf "Overview of Adult Traumatic Brain Injuries."] Retrieved on
2008-01-16 .External links
*
* [http://www.upei.ca/histology/assets/images/w-spinal-2.jpgSlide]ee also
*
Arachnoid cyst
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