A local anesthetic injected into the space outside the dura mater but within the spinal canal is placed into which space?

A local anesthetic injected into the space outside the dura mater but within the spinal canal is placed into which space?

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

Answer: (C)

The space outside the dura mater but inside the spinal canal is the epidural space. Injecting a local anesthetic there surrounds the exiting nerve roots in the epidural space, producing a regional (epidural) block without entering the cerebrospinal fluid. The subarachnoid space lies deeper, contains CSF, and injections into it are intrathecal. The subdural space is a potential gap between dura and arachnoid and is not a typical site for these injections, and intrathecal refers specifically to delivering into the subarachnoid space within the thecal sac. So, the space described is the epidural space.

The space outside the dura mater but inside the spinal canal is the epidural space. Injecting a local anesthetic there surrounds the exiting nerve roots in the epidural space, producing a regional (epidural) block without entering the cerebrospinal fluid. The subarachnoid space lies deeper, contains CSF, and injections into it are intrathecal. The subdural space is a potential gap between dura and arachnoid and is not a typical site for these injections, and intrathecal refers specifically to delivering into the subarachnoid space within the thecal sac. So, the space described is the epidural space.