Abstract
1) In 800 autopsy cases, 9 aneurysms of the cerebral arteries and a case of arteriovenous aneurysm were found. 8 cases were males and 2 cases females.
2) A case of arterio-venous aneurysm was 5 years old. In 9 aneurysms of the cerebral arteries, a case was in the 2nd decade, 3 cases were in the 3rd decade, 2 cases in the 4th decade, a case in the 5th decade and a case was in the 6th decade.
3) Localization: 3 cases were found at the a. communicans anterior, 3 cases at the a. carotis interna, a case at the a, cerebri media and 2 cases at the a. basilaris. A case of the arterio-venous aneurysm was found at the a. cerebri media. A case of aneurysms at the a. cerebri media, two aneurysms were found in both sides.
4) In histological examination, the walls of the aneurysms were observed thin and fibrous, but in some areas there were localized thickening of the walls. In most cases the lamina elastica interna were not seen, but in some cases the fragments of the lamina elastica interna were found. Sudden disappearance of the lamina elastics interna at the transitional region between the aneurysm and the normal arteries were found in most cases, but in some cases disappeared gradually. In 9 aneurysms, 8 cases were regarded as congenital in origin, a case was as arteriosclerotic in origin.
