There are three meninges covering the brain: the dura mater, the arachnoid mater, and the pia mater.

• The dura mater is the thickest and strongest membrane, and is firmly attached to the inner surface of the cranial bone, especially along the sutures. It contains the meningeal arteries.

• The arachnoid mater is a thin membrane under the dura mater. Its inner surface has numerous thin trabeculae extending downward, into the subarachnoid space.

• The pia mater is a thin membrane that covers the surface of the brain, entering the grooves and fissures.

Due to the tight adhesion of the dura mater to the inner skull, significant force is required to separate them. In contrast, separation of the dura from the subarachnoid mater can occur with relatively little force.

The middle meningeal artery arises from the external carotid artery. It enters the foramen spinosum and branches into the anterior, middle, and posterior branches with various patterns. It is a common source of bleeding in acute epidural hematomas (EDHs).

The bridging veins connect the cortical superficial veins to the sagittal sinus in the dura. They are a common source of bleeding in acute subdural hematomas (SDHs).