Which disorder primarily involves the arteries?

The correct choice focuses on aneurysms, which are localized dilations or bulges in the wall of an artery caused by weakness in the arterial wall. This disorder primarily affects arteries as it occurs when there is a weakening of the vessel wall, leading to an abnormal enlargement that can rupture or lead to serious complications.

Aneurysms can occur in any artery but are most commonly found in the aorta. The conditions can be indicative of underlying issues such as high blood pressure or atherosclerosis, which further highlights their connection to arterial health. Understanding the direct relationship between aneurysms and the arteries allows professionals to not only diagnose but also manage potential risks associated with this disorder effectively.

The other disorders listed, while important, do not primarily involve arteries. Infarction refers to tissue death due to insufficient blood supply, which may involve arteries indirectly, but is more about the end tissues affected. Fibrosarcoma is a type of cancer that affects connective tissues, and endocarditis is an infection of the inner lining of the heart, specifically the heart valves. These conditions involve different systems in the body and thus do not align with the arterial focus of aneurysms.