What is a sub arachnoid haemorrhage and a subdural haemorrhage?

Described below: A subarachnoid hemorrhage is an arterial bleed usually from the rupture of a saccular aneurysm, though it can be traumatic. Blood accumulates over the surface of the brain and a fine covering called the pia-arachnoid. A subdural hemorrhage is a venous bleed from bridging veins . It occurs between the inner lining of the skull and the tough covering of the brain called dura. Both a dangerous.