Corpus: Epidural space

The epidural space, also known clinically as the peridural space, is an anatomical cleft space that occurs in the area of the spinal cord membranes or the spinal canal. It lies between the dural sac and the periosteal-lined wall of the spinal canal.

The dura mater spinalis envelops the spinal cord as an elongated dural sac in the entire area of the spinal column. In contrast to the cranial dura mater, it is not connected to the periosteum of the vertebral bodies, so that the dural sac is surrounded by the epidural space. This is filled with loose connective tissue and fatty tissue and contains the internal vertebral venous plexus. The epidural space ends approximately at the level of the 2nd sacral vertebral body (SWK 2), slightly lower in newborns (SWK 4), where the dural sac merges into the pars duralis of the filum terminale.

Nomenclature[Bearbeiten]

In some textbooks, the periosteum of the vertebral bodies is referred to as the outer layer of the dura mater (endorhachis), while the dural sac is formed by the inner layer ("stratum mengeale"). According to this view, the epidural space is located between the inner and outer layer of the dura, but would then be more of an "intradural space".

The epidural space is not physiologically present in the area of the brain, as the stratum fibrosum of the dura simultaneously forms the periosteum of the cranial cavity. However, a so-called epidural haemorrhage can occur after a traumatic brain injury, for example. It is localised between the dura mater and the bone. The meningeal artery is often the source of the haemorrhage, as it runs directly along the inner wall of the cranial vault. Epidural haemorrhage in the area of the spinal column is rare.

By puncturing the epidural space and applying a local anaesthetic, anaesthesia of the exiting nerves can be achieved (epidural anaesthesia). In spinal anaesthesia, on the other hand, the local anaesthetic is applied to the subarachnoid space.