Deep vein thrombosis
Most deep vein blood clots occur in the lower leg or thigh, but can also occur in other parts of the body.
A blood clot in a deep vein can break off and travel through the bloodstream. The loose clot is called an embolus. When the clot travels to the lungs and blocks blood flow, the condition is called pulmonary embolism (PULL-mun-ary EM-bo-lizm), or PE.
Blood clots in the thigh are more likely to break off and cause a pulmonary embolism than blood clots in the lower leg or other parts of the body.
Blood clots also can form in the veins closer to the skin's surface, but are less serious because these will not break off and cause a pulmonary embolism.
- Blood clots occur when blood thickens and clumps together.