A leg aneurysm is a weak, bulging area located in the wall of a blood vessel found in the thigh, knee or calf. It is the result of an anomalous expansion to greater than 150 percent of the normal width of the blood vessel. Although there are several known symptoms, more often there are no symptoms to alert an individual a leg aneurysm exists. Treatment includes making lifestyle changes, medication and surgery.

There are two types of leg aneurysms. An aneurysm located in the femoral artery in the thigh is called a femoral aneurysm. The second type of leg aneurysm is found in the popliteal artery, which supplies blood for the knee, thigh and calf. The popliteal artery can burst, causing bleeding that is life-threatening. A popliteal aneurysm also can cause a blood clot, which could require amputation of the leg.

A person with a leg aneurysm will not always experience symptoms, making it nearly impossible to know that there is any need for concern. Symptoms that are experienced depend on the type of leg aneurysm. The most common sign of a femoral aneurysm is a pulsing sensation of the femoral artery in the groin. Common symptoms of a popliteal aneurysm include pulsing of the popliteal artery in the back of the knee, watery fluid in the lower leg, foot pain and skin ulcers on the foot that will not heal.

Femoral and popliteal aneurysms do not have known causes, but there are several factors that can come into play. Atherosclerosis is the buildup of fatty substances and plaque, which harden the artery and play a role in causing an aneurysm. Trauma to an artery is another contributing factor. Congenital disorders also can play a part in the formation of a leg aneurysm.

The diagnosis for a leg aneurysm is made by a physician using one or more of several procedures. Detailed images of the aortic artery are seen using a computed axial tomography (CT or CAT) scan. A magnetic resonance imaging (MRI) test might be performed to construct an image of the location where the aneurysm might be. Another method used for diagnosis is an angiography. A catheter is used to insert dye into the artery in order to track the blood flow, and it produces three-dimensional images of the aneurysm.

After the diagnosis is made, the doctor will choose a treatment program. Modifying certain risk factors such as smoking, controlling blood sugar levels, weight loss and controlling dietary fat intake can reduce the risk of an aneurysm. Certain medications are used to control elevated levels of fat in the blood and to control high blood pressure. Surgery to replace the artery with a graft from other arteries or veins in the body could be required. A bypass surgery can be performed instead to bypass the area where the aneurysm is located.