A subdural hematoma (American spelling) or subdural haematoma (British spelling), also known as a subdural haemorrhage (SDH), is a type of hematoma, usually associated with traumatic brain injury. Blood gathers between the dura mater, and the brain. Usually resulting from tears in bridging veins which cross the subdural space, subdural hemorrhages may cause an increase in intracranial pressure (ICP), which can cause compression of and damage to delicate brain tissue. Subdural hematomas are often life-threatening when acute. Chronic subdural hematomas, however, have a better prognosis if properly managed.