The space between the dura mater and arachnoid mater is called:

• A. Epidural
• B. Subarachnoid
• C. Intrathecal
• D. Subdural

Answer: (D)

Understand the arrangement of the meninges and the spaces between them. The dura mater is the outermost layer, followed by the arachnoid mater, then the pia mater. The space between the dura mater and the arachnoid mater is called the subdural space. It’s a potential space that can become real if something like bleeding or fluid accumulates, forming a subdural hematoma or effusion. This space is distinct from the subarachnoid space, which lies between the arachnoid and the pia and normally contains cerebrospinal fluid, and from the epidural space, which is between the dura and the skull or vertebral wall. Intrathecal refers to administration into the cerebrospinal fluid-containing space within the thecal sac, not to a specific meningeal space. So the space between the dura and arachnoid is subdural.