See also: List of states and territories of the United States. This table includes abbreviations for three independent nations related to the United States through Compacts of Free Association, and other comparable postal abbreviations, including those now obsolete. Codes and abbreviations for U.S. states, territories and other regions.
Pulmonary embolism is the sudden blockage of a major blood vessel (artery) in the lung, usually by a blood clot . In most cases, the clots are small and are not deadly, but they can damage the lung. But if the clot is large and stops blood flow to the lung, it can be deadly.
Pulmonary embolism is caused by a blocked artery in the lungs. The most common cause of such a blockage is a blood clot that forms in a deep vein in the leg and travels to the lungs, where it becomes lodged in a smaller lung artery. Almost all blood clots that cause pulmonary embolism are formed in the deep leg veins.Clots also can form in the deep veins of the arms or pelvis.f a large blood clot blocks the artery in the lung, blood flow may be completely stopped, causing sudden death. A smaller clot reduces the blood flow and may cause damage to lung tissue. But if the clot dissolves on its own, it may not cause any major problems. Symptoms of pulmonary embolism usually begin suddenly.