Aneurysm
Aneurysm is a bulge or sac formed by the ballooning of the wall of an artery or a vein . An aneurysm may pose a threat to health. It may become the site of a blood clot that breaks away and lodges in the tissues of such vital organs as the heart and the brain , causing serious, even mortal, heart failure or brain damage. A ruptured aneurysm may lead to a fatal loss of blood from the circulatory system into body cavities. Most aneurysms occur in blood vessel walls that have been weakened by a combination of arteriosclerosis, thickening and hardening of the arteries, and hypertension, abnormally high blood pressure. However, even normal blood pressure may cause an aneurysm in a vessel wall that has been weak from birth. Other causes of aneurysms include traumatic injury, such as that experienced in an automobile accident, and infection from diseases, such as syphilis. Aneurysms may develop in any blood vessel, but they frequently form in the major vessels, especially in the aorta, whic