Opens in a new tab
Home › Body Atlas › Brain & Spinal Cord › Posterior Epidural Space
Brain Structure Spine

Posterior Epidural Space

spatium epidurale posterius

The posterior epidural space lies between the posterior dura mater and the ligamentum flavum and laminae, containing epidural fat, the posterior internal vertebral venous plexus, and radicular vessels. It is wider and more clinically accessible than the anterior epidural space, being the target for epidural steroid injections, spinal cord stimulator lead placement, and epidural catheter insertion.

Anatomical Data

Structure & Connections

LocationBack of the vertebral canal, between the dural sac and the ligamenta flava and laminae
Parts
  • Epidural fat (thickest in the lumbar region)
  • Posterior internal vertebral venous plexus
  • Radicular vessels
Connections
  • Anterior and lateral epidural space
  • Intervertebral foramina
Blood SupplySpinal branches of segmental arteries
Biomechanics

Function & Actions

The roomiest part of the epidural space and the one entered by an epidural needle after it passes the ligamentum flavum. Lead wires for spinal cord stimulators are placed here.

Clinical Relevance

Clinical Notes

The posterior epidural space is entered via the interlaminar or transforaminal route for epidural steroid injections in lumbar radiculopathy and spinal stenosis. Its fat content varies with BMI and age. Obese patients have proportionally larger posterior epidural fat pads. Loss of resistance technique identifies entry into this space. The space narrows in spinal stenosis as ligamentum flavum hypertrophy compresses it. Spinal cord stimulator leads are placed in this space for chronic pain management.

Pathology

Common Injuries & Conditions

Posterior Epidural Haematoma Expansion

Expanding haematoma in the posterior epidural space from coagulopathy or iatrogenic vessel injury producing progressive myelopathy, requiring urgent MRI and emergency surgical decompression.

This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.

Accept All Accept Required Only