The epidural space is the region located between the dura mater (the outermost membrane covering the spinal cord and brain) and the osteoligamentous structures lining the vertebral canal (the bony and ligamentous walls of the spinal canal).
Detailed Explanation
The epidural space essentially surrounds the dural sac and contains:
- Fat: Provides cushioning and support.
- Blood vessels: Including the internal vertebral venous plexus (Batson's plexus).
- Nerve roots: As they exit the dural sac and travel towards their respective foramina.
- Connective tissue: Provides structural support.
Location and Extent
The epidural space extends from the foramen magnum (the opening at the base of the skull) down to the sacral hiatus (an opening in the sacrum). It terminates roughly at the S4 and S5 vertebral levels. While a continuous space, it can be conceptually divided into anterior and posterior compartments.
Clinical Significance
The epidural space is clinically significant as the target location for epidural anesthesia and analgesia. Medications injected into this space can block nerve transmission, providing pain relief or anesthesia for procedures such as childbirth or surgery.
