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Potential space between the arachnoid and dura maters
The subdural space (or subdural cavity) is a potential space that can be opened by the separation of the arachnoid mater from the dura mater as the result of trauma, pathologic process, or the absence of cerebrospinal fluid as seen in a cadaver. In the cadaver, due to the absence of cerebrospinal fluid in the subarachnoid space, the arachnoid mater falls away from the dura mater. It may also be the site of trauma, such as a subdural hematoma, causing abnormal separation of dura and arachnoid mater. Hence, the subdural space is referred to as "potential" or "artificial" space.
Diagrammatic representation of a section across the top of the skull, showing the membranes of the brain, etc. ("Subdural cavity" visible at left.)
Diagrammatic transverse section of the medulla spinalis and its membranes. (Subdural cavity is colored green, labeled at bottom and top right.)
This article incorporates text in the public domain from page 875 of the 20th edition of Gray's Anatomy (1918)
