The dura mater also forms several vein-like sinuses that carry blood which has already given its supply of oxygen and nutrients to the brain back toward the heart. The superior sagittal sinus runs across the top of the brain in an anterior-posterior direction. Other sinuses include the straight sinus, the inferior sinus, and the transverse sinus. The epidural space is a potential space that may exist between the dura mater and the skull. If there is hemorrhaging in the brain, blood may collect here.
Adults tend to bleed here as a result of closed head injury.
The subdural space is another potential space that may exist between the dura mater and the medial layer of the meninges, the arachnoid mater. When bleeding occurs in the cranium, blood may collect here and push down on the lower layers of the meninges. If bleeding continues, brain damage will result from this pressure. Children are especially likely to have bleeding in the subdural space in cases of head injury. The arachnoid or arachnoid mater is the middle layer of the meninges.