A pulmonary embolism is a blood clot that travels
to the lungs. Often, the clot forms in another part of the body, usually in
the veins of the legs. Large clots can be fatal. The January 11, 2006, issue
of JAMA includes an article about diagnosing pulmonary
embolism. This Patient Page is based on one previously published in the December
3, 2003, issue of JAMA.