The dural sheath is a protective covering that surrounds the spinal cord and the roots of spinal nerves. It is made of tough, fibrous tissue, which helps to shield these vital structures from injury and infection. The sheath is part of the larger protective system that includes the dura mater, one of the three layers of membranes known as the meninges. In addition to providing protection, the dural sheath also plays a role in the flow of cerebrospinal fluid (CSF), which nourishes and cushions the spinal cord. This fluid circulates within the subarachnoid space, located between the dural sheath and the spinal cord, helping to maintain a stable environment for the nervous system.