The specimen is an adult brain sectioned in the mid-saggital and horizontal planes. There is a
blood filled aneurysm situated at the bifurcation of the basilar artery. The third ventricle is dilated
and the lateral ventricles and fourth ventricle contain copious amounts of blood. There is
haemorrhage into the subarachnoid space over the lobe of the cerebellum and the inferior
surface of the pons. The features are those of subarachnoid and interventricular haemorrhage
arising from a ruptured aneurysm situated at the bifurcation of the basilar artery.