- Literally, beneath the arachnoid, the middle of three membranes that cover the central nervous system. In practice, subarachnoid usually refers to the space between the arachnoid and the pia mater, the innermost membrane surrounding the central nervous system. The subarachnoid space is a potential space. It normally contains cerebrospinal fluid. A subarachnoid hemorrhage is a bleed into this space. The arachnoid is named for its delicate, spider-web-like filaments that extend from its undersurface through the cerebrospinal fluid in the subarachnoid space to the pia mater. "Arachnoid" comes from the Greek "arachne" meaning spider or cobweb + "eidos" meaning resemblance = spider-web-like.
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* * *sub·arach·noid .səb-ə-'rak-.nȯid also sub·arach·noid·al -rak-'nȯid-əl adj1) situated or occurring under the arachnoid membrane <\subarachnoid hemorrhage>2) of, relating to, or involving the subarachnoid space and the fluid within it <\subarachnoid meningitis>
* * *sub·arach·noid (sub″ə-rakґnoid) between the arachnoid and the pia mater.
Medical dictionary. 2011.
Look at other dictionaries:
subarachnoid — [sub΄ə rak′noid΄] adj. located in the space between the arachnoid and the pia mater membranes of the brain and spinal cord, that contains the cerebrospinal fluid [a subarachnoid hemorrhage] … English World dictionary
Subarachnoid — Sub a*rach noid, Subarachnoidal Sub*ar ach*noid al, a. (Anat.) Situated under the arachnoid membrane. [1913 Webster] … The Collaborative International Dictionary of English
subarachnoid — “+ adjective Etymology: International Scientific Vocabulary sub + arachnoid : of, relating to, or situated under the arachnoid membrane subarachnoid processes as a. : constituting the space between the arachnoid membrane and the pia mater b … Useful english dictionary
subarachnoid — also subarachnoidal adjective Date: 1843 of, relating to, occurring, or situated under the arachnoid membrane < subarachnoid hemorrhage > … New Collegiate Dictionary
subarachnoid — /sub euh rak noyd/, adj. Anat. of, pertaining to, or situated below the arachnoid membrane. [1830 40; SUB + ARACHNOID] * * * … Universalium
subarachnoid — adjective Located or occurring below the arachnoid mater, often specifically between the arachnoid membrane and the pia mater … Wiktionary
subarachnoid — adj. of or pertaining to the arachnoid membrane, located below the arachnoid membrane (Anatomy) … English contemporary dictionary
subarachnoid — adjective Anatomy denoting or occurring in the fluid filled space around the brain between the arachnoid membrane and the pia mater, through which major blood vessels pass … English new terms dictionary
subarachnoid — sub·arachnoid … English syllables
subarachnoid — sub a•rach′noid adj … From formal English to slang