Assertion: arachnoid | /r/CapableOf | envelop the brain and medulla spinalis
Facets:
Source sentences:
text: The arachnoid is a delicate membrane enveloping the brain and medulla spinalis and lying between the pia mater internally and the dura mater externally; it is separated from the pia mater by the subarachnoid cavity, which is filled with cerebrospinal fluid.