Question

multiple choice 2 points

epidural anesthesia is introduced to the epidural space between the ________ to block pain signals during pregnancy.

dural sheath and vertebral bones
dura mater and arachnoid mater
dural sheath and dura mater
arachnoid mater and pia mater
dura mater and pia mater

Explanation:

Identify the anatomical location of the epidural space

The question asks for the anatomical boundaries of the epidural space where epidural anesthesia is introduced. By definition, the prefix "epi-" means "upon" or "outside." Therefore, the epidural space is the space located outside the outermost meningeal layer, which is the dura mater (or dural sheath in the spinal cord).

Analyze the surrounding structures

Using the Meningeal Layers knowledge point, we recall that the spinal cord is protected by three meningeal layers: the dura mater (outermost), the arachnoid mater (middle), and the pia mater (innermost). The dural sheath is surrounded externally by the bony vertebral canal. The space between the dural sheath and the vertebral bones contains adipose tissue, connective tissue, and blood vessels. This region is the epidural space.

Evaluate the given multiple-choice options

• dural sheath and vertebral bones: This correctly describes the epidural space, which lies outside the dural sheath and inside the vertebral canal.
• dura mater and arachnoid mater: This describes the subdural space (a potential space).
• dural sheath and dura mater: These terms refer to the same protective layer in this context, so there is no space between them.
• arachnoid mater and pia mater: This describes the subarachnoid space, which contains cerebrospinal fluid (CSF).
• dura mater and pia mater: This spans multiple layers and is not a single anatomical space.

Thus, the correct boundary is between the dural sheath and the vertebral bones.

Answer:

• (A) dural sheath and vertebral bones (Correct answer)
• (B) dura mater and arachnoid mater
• (C) dural sheath and dura mater
• (D) arachnoid mater and pia mater
• (E) dura mater and pia mater