(See also Aortic Branch Aneurysms Aortic Branch Aneurysms Aortic branch aneurysms are bulges (dilations) in the wall of the major arteries that come directly off of the aorta. (See also Overview of Aortic Aneurysms and Aortic Dissection.) The aorta... read more and Brain Aneurysms Brain Aneurysms An aneurysm is a bulge (dilation) in the wall of an artery. Aneurysms that occur in the arteries of the brain (cerebral arteries) are called cerebral aneurysms. Aneurysms may occur in any artery... read more .)
Aneurysms may occur in any artery. Aneurysms are most common in the aorta Overview of Aortic Aneurysms and Aortic Dissection The aorta, which is about 1 inch (2.5 centimeters) in diameter, is the largest artery of the body. It receives oxygen-rich blood from the left ventricle of the heart and distributes it to all... read more , which is the main artery that carries blood from the heart to the body. The aorta is located in the torso. Aneurysms may also occur in arteries outside the torso, including those in the
Legs (femoral arteries in the thighs, popliteal arteries behind the knees)
Heart (coronary arteries)
Neck (carotid arteries)
Aneurysms of the carotid arteries are rare. Older people are more likely to have aneurysms than are younger people.
Causes
Many aneurysms result from a weakness in the artery wall that is present at birth (congenital) or from atherosclerosis Atherosclerosis Atherosclerosis is a condition in which patchy deposits of fatty material (atheromas or atherosclerotic plaques) develop in the walls of medium-sized and large arteries, leading to reduced or... read more 
(buildup of plaque or fatty material in the wall of blood vessels). Others result from injuries caused by stab or gunshot wounds or from bacterial or fungal infections in the wall of the artery that develop after recreational use of intravenous drugs such as heroin. Such infections usually start elsewhere in the body, typically in a heart valve Infective Endocarditis Infective endocarditis is an infection of the lining of the heart (endocardium) and usually also of the heart valves. Infective endocarditis occurs when bacteria enter the bloodstream and travel... read more 
, before spreading to the wall of the artery.
Symptoms
Most popliteal and femoral aneurysms do not cause symptoms. However, blood clots can form within the aneurysm. If these blood clots break loose, they are called emboli. Emboli can move with the blood flow until they block an artery in the lower leg or foot Occlusive Peripheral Arterial Disease Occlusive peripheral arterial disease is blockage or narrowing of an artery in the legs (or rarely the arms), usually due to atherosclerosis and resulting in decreased blood flow. Symptoms depend... read more 
, causing sudden onset of severe pain, numbness, and coolness of the foot, which may also appear pale.
Emboli from carotid aneurysms can block an artery in the brain and cause a stroke Overview of Stroke A stroke occurs when an artery to the brain becomes blocked or ruptures, resulting in death of an area of brain tissue due to loss of its blood supply (cerebral infarction) and symptoms that... read more .
Emboli from aneurysms in the arteries of the heart (coronary arteries) can result in symptoms of a heart attack Acute Coronary Syndromes (Heart Attack; Myocardial Infarction; Unstable Angina) Acute coronary syndromes result from a sudden blockage in a coronary artery. This blockage causes unstable angina or a heart attack (myocardial infarction), depending on the location and amount... read more 
(such as chest pain and shortness of breath).
Unlike aneurysms in the aorta or cerebral arteries, aneurysms in the popliteal, femoral, coronary, and carotid arteries rarely rupture.
Diagnosis
Imaging
Doctors may diagnose aneurysms in the legs or arms by feeling a pulsating mass in the affected artery. Ultrasonography or computed tomography (CT) can confirm the diagnosis. Aneurysms of arteries in the heart require other imaging studies, such as conventional angiography Angiography In angiography, x-rays are used to produce detailed images of blood vessels. It is sometimes called conventional angiography to distinguish it from computed tomography (CT) angiography and magnetic... read more , CT angiography CT angiography In computed tomography (CT), which used to be called computed axial tomography (CAT), an x-ray source and x-ray detector rotate around a person. In modern scanners, the x-ray detector usually... read more 
, or magnetic resonance angiography Magnetic resonance angiography (MRA) In magnetic resonance imaging (MRI), a strong magnetic field and very high frequency radio waves are used to produce highly detailed images. MRI does not use x-rays and is usually very safe... read more 
.
Treatment
Surgery or stent-graft repair
Doctors repair aneurysms in the lower part of the body when the aneurysm is twice the size of the normal blood vessel or when the person develops symptoms. Aneurysms in the arms are usually repaired right away even if the person has no symptoms because there is a higher chance that a blood clot will form in these blood vessels.
For popliteal aneurysms larger than 1 inch (2.5 centimeters) in diameter, open surgery or placement of a stent-graft within the aneurysm is usually done. A stent-graft is a hollow tube of synthetic material with a springy mesh in its wall. The mesh wall, like a collapsible straw, allows the stent to be compressed small enough to be inserted into an artery over a long thin wire. Doctors pass the stent through the artery to the aneurysm. Then the stent-graft is opened, forming a stable channel for blood flow. Stent-grafts can also be used for coronary aneurysms, although these sometimes require coronary artery bypass surgery Percutaneous Coronary Intervention Coronary artery disease is a condition in which the blood supply to the heart muscle is partially or completely blocked. The heart muscle needs a constant supply of oxygen-rich blood. The coronary... read more 
. Usually, femoral and carotid aneurysms are surgically repaired.
Infected aneurysms typically require treatment with antibiotics or antifungal drugs and may require surgery, depending on where the aneurysm is located, how big it is, and how much it has been damaged by the infection.
