duramater

Dura mater, also known as the duramater, is the tough outermost layer of the meninges that surround the brain and spinal cord. In the cranium it consists of two layered sheets: the periosteal layer, which is attached to the inner surface of the skull, and the inner meningeal layer. In the spinal canal, the dura mater is a single layer that forms the dural sac enveloping the spinal cord.

The inner surface of the dura folds inward to create partitions such as the falx cerebri, the falx cerebelli, the tentorium cerebelli, and the diaphragma sellae, which compartmentalize the brain. Between the periosteal and meningeal layers in the skull lies the dural venous sinuses, a network of channels that drain venous blood from the brain toward the internal jugular veins. A potential epidural space exists between the skull and the dura; in the spine there is a real epidural space that contains fat and valves. The dura is supplied by meningeal arteries and innervated by meningeal nerves, making it sensitive to pain.

Functionally, the dura provides protective support and helps form a rigid framework that stabilizes the brain within the skull. It also contributes to the compartmental organization of the cranial cavity and serves as part of the barrier between the nervous system and the systemic circulation.

Clinical relevance includes epidural hematoma, typically from rupture of the middle meningeal artery after trauma, between skull and dura; and subdural hematoma, from tearing of bridging veins between dura and arachnoid. Dural puncture can cause intracranial hypotension and postdural puncture headaches; the dura is also involved in various inflammatory processes and is a consideration in spinal or cranial procedures.