The etiology of aneurysms is multifactorial and includes changes in the elastin and collagen makeup of the arterial walls causing degeneration, atherosclerosis, trauma, infection (rarely, syphilis) inflammatory processes, (e.g., Takayasu’s arteritis), and genetic and connective tissue disorders (e.g., Ehlers-Danlos type IV, Marfan’s syndrome, Loewi’s-Dietz syndrome).