blood accumulation that separates the dura from the inner side of the skull is known as an epidural hematoma (blood swelling). The same process occurrence between the dura and arachnoid layers is a subdural hematoma

A Subdural Hematoma occurs when a severe acceleration to deceleration occurs leading to the veins in the subdural space tearing. An Epidural Hematoma occurs from direct trauma to the brain leading to bleeding in the meningeal artery.

Trauma is a common cause of spinal epidural hematoma. Non-trauma causes include anticoagulant therapy, hemophilia, liver disease, aspirin use, systemic lupus erythematosus.

Epidural hematoma

An epidural hematoma is a pocket of blood that forms immediately outside the dura mater. The dura mater is the fibrous outermost sheath or membrane that encloses the brain and spinal cord.