Caption:
Medical illustration of two types of brain injuries, a subarachnoid haemorrhage (left) and a subdural hematoma (right). Subarachnoid haemorrhage (SAH) is bleeding into the subarachnoid space, the area between the arachnoid membrane and the pia mater surrounding the brain. A subdural hematoma, also known as a subdural haemorrhage (SDH), is a type of hematoma, usually associated with traumatic brain injury. Blood gathers between the inner layer of the dura mater and the arachnoid mater.