The specimen is a brain sectioned in the horizontal plane. Examination of the Circle of Willis
shows a small aneurysm of the right middle cerebral artery, situated immediately proximal to its
bifurcation. There is a subarachnoid haemorrhage arising from the aneurysm, this extends into
the right sylvian fissure and over the right temporal lobe. Foci of haemorrhage are also seen on
the lateral aspect of both lobes of the cerebellum. The brain is oedematous in the vicinity of the
subarachnoid haemorrhage and there is pronounced midline shift to the left. Herniation of the
cerebellar tonsils provides evidence of raised intracranial pressure.
This 56 year old woman was admitted to hospital, after a sudden collapse. Subarachnoid
haemorrhage was diagnosed. She regained consciousness but deteriorated following a further
subarachnoid haemorrhage some two weeks later. Death was due to bronchopneumonia.