In anatomy, the epidural space is the potential space between the dura mater and vertebrae (spine).
The anatomy term "epidural space" has its origin in the Ancient Greek language; , "on, upon" + dura mater also known as "epidural cavity", "extradural space" or "peridural space". In humans the epidural space contains lymphatics, spinal nerve roots, loose connective tissue, adipose tissue, small arteries, dural venous sinuses and a network of internal vertebral venous plexuses.
Cranial epidural space
In the skull, the periosteal layer of the dura mater adheres to the inner surface of the skull bones while the meningeal layer lays over the arachnoid mater. Between them is the epidural space. The two layers of the dura mater separate at several places, with the meningeal layer projecting deeper into the brain parenchyma forming fibrous septa that compartmentalize the brain tissue. At these sites, the epidural space is wide enough to house the epidural venous sinuses.
There are four fibrous septa:
Epidural space is the smallest at the cervical region, measuring 1 to 2 mm. At L2 to L3, enlarges until 5 to 6 mm. It then enlarges progressively until lower lumbar and sacral region. However, some authors stated that it decreases in size after mid-lumbar region until 2 mm at S1 level.
See also
- Subarachnoid space
- Subdural space
- Meninges