Glossary term:

Dura

This is the outer, most prominent and the toughest of the three different membranes that invest the brain and spinal cord. It also forms the lining of the cranial cavity and the spinal canal. Looked at as a whole, the dura can be envisaged as a balloon with a long sausage skin hanging below it. Within the dura the brain and spinal cord are bathed in cerebrospinal fluid.