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.
What causes a pulmonary embolism? Blood clots can form for a variety of reasons. Pulmonary embolisms are most often caused by deep vein thrombosis, a condition in which blood clots form in veins deep in the body. The blood clots that most often cause pulmonary embolisms begin in the legs or pelvis.