Which of the following is NOT considered an etiology of arterial aneurysms?

The correct answer indicates that "saccular" is not considered an etiology of arterial aneurysms, but rather a specific type of aneurysm. Aneurysms can be classified into various shapes, and a saccular aneurysm refers to a type characterized by a localized outpouching on one side of the artery wall.

In contrast, the other options, such as congenital weakness, atherosclerosis, and trauma, are all recognized causes or risk factors for developing arterial aneurysms. Congenital weaknesses in the arterial wall can predispose individuals to the formation of an aneurysm. Atherosclerosis, which involves the buildup of plaque inside the arteries, can weaken the vessel wall over time, leading to aneurysm formation. Trauma can also result in vascular damage that may contribute to the development of an aneurysm.

Thus, while the term “saccular” describes a type of aneurysm, it does not categorize the underlying causes that lead to the formation of the aneurysm itself.