Within the spinal canal, the spinal cord is surrounded by the EPIDURAL SPACE. This space is filled with fatty tissue, veins, and arteries. The fatty tissue acts as a shock absorber and keeps the spinal cord from contacting the bony tissue of the vertebrae.
The brain and spinal cord are covered by three layers of material, called Meninges. The main function of these layers is to protect and feed the delicate neurological structures.
The DURA MATER is the outermost meningeal layer and is made up of strong connective tissue. Also called the DURA, it is gray in color and generally easy to identify within the spinal canal. The dura extends around each nerve root and becomes contiguous with the EPINEURUM, a membrane covering the spinal nerves
The SUBDURAL SPACE is a very small space between the dura and the next meningeal layer, the ARACHNOID. The arachnoid layer is highly vascularized with a web of arteries and veins that give the impression of a spider wed. It is thinner than the dura and is subject to injury.
Below the arachnoid is the SUBARACHNOID SPACE, which is filled with CEREBROSPINAL FLUID (CSF). The CSF helps to protect the nerve structures by acting as a shock absorber. It also contains various electrolytes, protect, and glucose. A spinal tap can be inserted into the subarachnoid space to retrieve CSF for various chemical analyses.
The innermost lining of the meninges is called the PIA MATER. It is closely adhered to the spinal cord and the individual nerve roots. It is highly vascular and supplies blood to the neuro-logical structures.
Reference: http://www.back.com/
The information provided aims to provide educational purpose, if you have the described conditions as above, please consult your neurosurgeon.