Subdural space

Last revised by Craig Hacking on 4 Oct 2020

The subdural space (epiarachnoid space) is a potential space that exists between the meningeal layer of the dura mater and the inner arachnoid mater of the leptomeninges which are adherent to each other 1.

Gross anatomy

The meningeal layer of dura mater is usually adherent to the underlying arachnoid mater via a series of tight junctions. The subdural space does not exist under normal circumstances and is appreciable only when there is underlying pathology 2.

Bridging veins drain from the underlying brain to the dura mater and the superior sagittal sinus. They have a relatively straight course and do not allow for much movement of the underlying brain tissue. Thus, they are easily placed under high tension. This is particularly important in the elderly where the underlying atrophic brain places these vessels under higher than normal tension 3.

Bleeding from bridging veins may strip the dura from the arachnoid mater. This collection of blood is known as a subdural hematoma.

Related pathology

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Cases and figures

  • Figure 1
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