How are types of aneurysms?

• True aneurysm involves all three layers of the vessel. - A fusiform aneurysm affects the entire circumference of segment of the vessel resulting in a diffusely dilated lesion. - A saccular aneurysm involves only a portion of the circumference resulting in an outpouching of the vessel wall. • False aneurysms involve the inner layers of the aorta. It is a partial rupture of the aorta, contained by the adventitia