Question

spinal meninges and spaces
concerning the spinal cord, where is the epidural space?
between the arachnoid and dura maters
between the arachnoid and pia maters
external to the dura mater
between the two layers of the dura

Explanation:

The epidural space is a potential space that lies external to the dura mater. It contains fat, venous plexuses, and connective tissue. The space between the arachnoid and dura maters is the subdural space (potential). The space between the arachnoid and pia maters is the subarachnoid space (contains cerebrospinal fluid). There is no significant space between the two layers of the dura in the spinal cord (unlike in the brain where the dural venous sinuses are present between meningeal and periosteal dura).

Answer:

External to the dura mater.