duremère

The dura mater is the outermost of the three meninges, the membranes that enclose the brain and spinal cord. It is a tough, fibrous, and inelastic layer. The name dura mater is derived from Latin, meaning "tough mother." It is composed of two layers, an outer periosteal layer that adheres to the inner surface of the cranial bones, and an inner meningeal layer. In the skull, these two layers are tightly fused, except where they separate to form venous sinuses, which collect deoxygenated blood from the brain.

The dura mater plays a crucial role in protecting the central nervous system. Its toughness provides a strong barrier against physical trauma. It also helps to support the brain and spinal cord within their respective cavities. The dura mater is innervated by sensory nerves, which can contribute to headache when it is stretched or inflamed.

Within the cranial cavity, the dura mater forms several septa or folds that divide the space and support the brain. The falx cerebri separates the two cerebral hemispheres, the tentorium cerebelli separates the cerebrum from the cerebellum, and the diaphragma sellae covers the pituitary gland. In the vertebral canal, the dura mater is separated from the vertebrae by the epidural space, which contains fat and blood vessels. The dura mater is continuous with the epineurium of the cranial and spinal nerves.