Extradural haematoma. Coloured computed tomography (CT) scan of a section through the skull of a 57 year old with an extradural haematoma (orange, bottom), a solid mass of blood between the dura mater, the outer membrane of the brain, and the skull. It is due to a haemorrhage caused by a trauma to the head. The haematoma increases pressure within the skull, causing headache, drowsiness, vomiting, paralysis and in some cases death. Treatment is with surgical drainage of the haematoma and sealing of the bleeding blood vessel.