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.
Major Causes. Pulmonary embolism (PE) usually begins as a blood clot in a deep vein of the leg. This condition is called deep vein thrombosis. The clot can break free, travel through the bloodstream to the lungs, and block an artery. The animation below shows how a blood clot from a deep vein in the leg can travel to the lungs, causing pulmonary embolism.