Local anesthetic injected into the epidural space (area surrounding the spinal cord within the spinal canal) is referred to as:

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

Answer: (C)

Injecting a local anesthetic into the epidural space yields epidural anesthesia. The epidural space lies just outside the dura mater around the spinal cord, so the drug blocks the nerve roots as they exit the spinal cord, producing loss of sensation in the areas those nerves supply. This approach is commonly used for regional anesthesia in the lower body and for labor analgesia because it can be titrated and extended with a catheter.

If the anesthetic were injected into the subarachnoid space (intrathecal), it would enter the CSF and produce a more rapid and dense block. The subdural space is a potential space between the dura and arachnoid that’s not typically used for injections. Injecting into brain tissue would be intracerebral, which is not a route for spinal or regional anesthesia.