It is a collection of blood that occurs between the dura and the skull. Because the dura also covers the spinal cord, an epidural bleed can also occur in the spine. Most are due to physical trauma and produces an increase in intracranial pressure and can even be reflected in deviation of the midline of the brain structures and can be fatal. It comes from a rupture of the middle meningeal artery, which runs outside the dura mater and is known to have a high association with temporal bone fractures. When blood pools rapidly, brain compression and transtentorial herniation occur. In other cases, the blood accumulates in a matter of hours producing drowsiness, coma, and death.
