arachnoid mater


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Related to arachnoid mater: pia mater

a·rach·noid mat·er

[TA]
a delicate fibrous membrane forming the middle of the three coverings of the central nervous system. In life, the arachnoid (specifically the arachnoid barrier cell layer) is tenuously attached to the externally adjacent dura mater (specifically the dural border cell layer), and no natural space occurs at the dura-arachnoid interface. Thus, in a spinal puncture, dura mater and arachnoid are penetrated simultaneously as if a single layer. Separation of the arachnoid mater from the dura mater (usually through the dural-border cell layer) may result from traumatic or pathologic processes creating what is commonly, but incorrectly, called a subdural hematoma. The arachnoid mater is named for the delicate, spiderweblike filaments that extend from its deep surface, through the cerebrospinal fluid of the subarachnoid space, to the pia mater. See: cranial arachnoid mater, spinal arachnoid mater.
See also: leptomeninx.

arachnoid membrane

The increasingly preferred term for the weblike membrane covering the brain that lies between the outer (and much thicker) dura mater and the deeper pia mater, from which it is separated by the subarachnoid space through which CSF flows and is absorbed by the arachnoid granulations.

a·rach·noid mat·er

(ă-rak'noyd mā'tĕr) [TA]
A delicate fibrous membrane forming the middle of the three coverings of the central nervous system. In life the arachnoid (specifically the arachnoid barrier cell layer) is tenuously attached to the externally adjacent dura mater (specifically the dural border cells) and there is no naturally occurring space at the dura-arachnoid interface. Thus, in a spinal puncture, dura mater and arachnoid are penetrated simultaneously as if a single layer. Separation of the arachnoid mater from the dura mater (usually through the dural border cell layer) may result from traumatic or pathologic processes creating what is commonly, but quite incorrectly, called a subdural hematoma. The arachnoid mater is named for the delicate, spiderweblike filaments that extend from its deep surface, through the cerebrospinal fluid of the subarachnoid space, to the pia mater.
Synonym(s): arachnoidea mater [TA] , arachnoid membrane, arachnoidea, arachnoides.
[G. arachnē, spider, cobweb, + eidos, resemblance]

arachnoid mater

See ARACHNOID.

Arachnoid mater

One of three membranes that encase the brain and spinal cord. The arachnoid mater is the middle membrane.

Patient discussion about arachnoid mater

Q. What is the treatment for an arachnoid cyst? My 15 year old son has just been diagnosed with an arachnoid cyst. What is the treatment? Is an operation necessary?

A. An operation is not always necessary, it depends on the size and location of the cyst. I suggest you take your son to a neurologist or a neurosurgeon for further consult.

Q. info on arachnoid cyst in the right posterior fossa

A. Basically it's like a small sac filled with fluid. The problem is that the skull is a rigid closed space, which means that if there's something other than the brain, it'll occupy space, usually on expense of the brains' space. These kinds of problems are often referred to as "space occupying lesion".

It's usually congenital (i.e. develops during pregnancy), and even when it cause symptoms they develop slowly.

YOu can read more here (http://en.wikipedia.org/wiki/Arachnoid_cyst)

Q. Is there any problem, if an arachnoid cyst ,2cmx1.5cm size, rostral to cerebellar region left untreated? symptoms: repeated headaches, twitching of muscles, tiredness

A. An arachnoid cyst that leads to symptoms usually needs treatment. Mild symptoms as you suggested are ok to left untreated however gradual onset of new symptoms may arise such as seizures, paralysis and other complications, therefore once symptoms occur one should consider treatment.

More discussions about arachnoid mater
References in periodicals archive ?
At this point the dura and arachnoid mater are separately attached to the ganglia.
Hardy, in his study performed on postmortem dura and arachnoid mater, demonstrated an inability of soft epidural catheters to penetrate dura mater (42).
The onset of the block is somewhat intermediate between that of a subarachnoid and epidural block, because the nerves in the subdural space are covered with pia and arachnoid maters, as compared to the subarachnoid space where the nerves are sheathed by pia mater only and the epidural space where arachnoid, pia and dura mater envelop the nerves.