[Theories of intracranial aneurysm etiology].

The main theories of the origin of intracranial aneurysms as the most common vascular malformations are presented. Three main theories maintain that they are either the congenital, acquire or both of those defects. The presence of aneurysms in the bifurcations of the arteries with the loss of the muscle layer and the coexistence with other vascular malformations of the arteries and their rareness in children give the evidence of the acquire origin. The present theories join this two positions and take into consideration also the hemodynamic and inflammation as well as degeneration, atheromatosis, toxic and traumatic factors.