Cranial dura

The cranial dura mater is the dura mater inside the cranial cavity of the skull and envelops the brain. It has two sublayers: the outer periosteal/endosteal layer that covers the inner aspect of the skull, and the inner meningeal layer that surrounds the brain. From the foramen magnum downwards, the inner layer of the cranial dura mater continues as the spinal dura mater.

In certain areas, the inner layer of the cranial dura mater separates from the outer layer and extends into the brain, attaching to specific areas of the skull. This creates partitions or folds that divide different regions of the brain and provide support for its structure. You can find more information about these dural partitions here: falx cerebri, falx cerebelli, tentorium cerebelli, and diaphragma sellae.

The cranial dura mater contains a network of venous sinuses between its two layers. These sinuses carry venous blood and also allow cerebrospinal fluid (CSF) to drain into them through the subarachnoid villi/granulations. Here you can find more details on venous sinuses.

Understanding the important spaces associated with the dura mater is crucial. These spaces include the epidural and subdural spaces. The epidural space is between the periosteal dural layer and the skull bone, and arterial hemorrhages can occur there. The subdural space, found between the dura and arachnoid mater, is where venous subdural hemorrhages can occur. In terms of innervation, the dura mater receives nerves from the trigeminal, vagus, and the first three cervical spinal nerves. When the dura mater below the tentorium cerebellum is pulled or stretched, it can cause headaches in the back of the scalp and neck regions. Similarly, pulling or stretching the dura mater above the tentorium cerebellum can cause headaches in the head region.