Final answer:
A fusiform aneurysm affects the entire circumference of the aorta, which is the largest artery in the body originating from the left ventricle, descending to the abdominal region, and splitting into the common iliac arteries.
Step-by-step explanation:
A fusiform aneurysm is a type of aneurysm that involves the entire circumference of the aorta. Unlike saccular aneurysms, which have a pouch-like shape with a narrow neck, fusiform aneurysms affect a longer segment of the artery and have a spindle-like shape encompassing the entire arterial wall. The aorta, being the largest artery in the body, originates from the left ventricle and descends to the abdominal region, bifurcating into the common iliac arteries at the level of the fourth lumbar vertebra.
It is important to understand that the aorta comprises different regions: the ascending aorta, the aortic arch, and the descending aorta. The descending aorta is further divided into the thoracic and abdominal aorta based on whether it is above or below the diaphragm. Arteries branching from the aorta distribute blood throughout the entire body, making any aneurysm in the aorta a potentially serious condition that requires prompt medical attention.