This is a view of the cerebral hemispheres after brainstem and cerebellum have been removed at the level of the midbrain. There is circular marked atherosclerosis of the left posterior cerebral artery. The left occipital lobe (right side of the photograph) shows a collapsed cystic and pigmented area in the distribution of the posterior cerebral artery. Diagnosis #1. Atherosclerosis of the left posterior cerebral artery. #2. Old infarction, posterior cerebral artery distribution.