In the central nervous system, there are three different layers that cover the spinal cord and brain. These are called themeninges,and their three levels consist of the:pia, arachnoid, and dura mater. Bone is situated above these layers, followed by periosteum (a fibrous membrane that covers bone) and skin. The dura mater is the top layer of the meninges, lying beneath the bone tissue.
This material at times opens into sinus cavities (spaces) located around the skull. This is particularly notable with the dural venous sinuses. Here, liquids, like blood and cerebrospinal fluid, drain and collect into the internal jugular vein. Cerebrospinal fluid is a clear liquid that cushions the brain and spinal cord while also transporting nutrients, chemicals, and waste. Dura mater is also the home to meningeal veins.
Many types of medical conditions involve the dura mater. The most common come in the form of hematomas. Arterial bleeding can result in anepidural hematoma, which is when blood collects between the dura mater and the skull. If blood collects between the dura and arachnoid mater, asubdural hematomaresults. Also, there are some instances where the dura plays a major role in certain types of headaches.