Structure
The cranial dura mater is the most superficial of the three meningeal layers and covers the entire brain down to the foramen magnum, where it is continuous with the spinal dura mater. The cranial dura mater is a tough, fibrous, two-layer structure with the outer or periosteal dura forming the periosteum of the cranial bones and the inner of meningeal dura laying against the underlying arachnoid mater. For the most part these two dural layers are adhered, but they can be visualized at some dural sinuses where the venous cavity separates the periosteal and meningeal dural layers. The dura is pierced by bridging veins, which carry blood from the brain; emissary veins, which bring blood from the overlying bone; and arachnoid granulations, which bring cerebrospinal fluid to venous sinuses.
Related parts of the anatomy
Anatomical Relations
The meningeal cranial dura mater is closely applied to the surface of the brain. Additionally, it provides sheaths for each of the cranial nerves as they exit through their cranial foramina. The sheaths fuse with the epineurium of the nerve as it exits the skull. The dural sheath of the optic nerve is continuous with the sclera of the eyeball. The meningeal cranial dura also fuses with the outer adventitia of the major vessels, e.g. the internal carotid artery, when it enters the cranial cavity.
Since the meningeal cranial dura mater is in close contact with the brain, it reflects inwards at certain points known as dural folds. The first is the falx cerebri in which the meningeal dura runs down in the longitudinal fissure separating the two cerebral hemispheres. Second is the tentorium cerebelli, a dural fold that separates the cerebellum below from the cerebrum above. A third fold, the falx cerebelli, runs perpendicular to the tentorium cerebelli and separates the two cerebellar hemispheres. Lastly, the diaphragma sellae surrounds the pituitary stalk.
List of Clinical Correlates
- Epidural hematoma
- Subdural hematoma
- Headache
