Deep vein thrombosis is the formation of a clot in which location?

• A. The superficial veins of the leg
• B. The deep veins of an extremity
• C. The heart chambers
• D. The capillaries in the lungs

Answer: (B)

Deep vein thrombosis involves a clot forming in the deep venous system, most often in the legs. The deep veins, like the femoral, popliteal, tibial, and iliac veins, run within the muscles and are the usual site for DVT. This differs from clots that occur in superficial veins (which is a separate condition) or from clots in heart chambers or in the lungs themselves. A clot in the lungs would be a pulmonary embolism, typically arising from a DVT that has traveled from a deep vein to the pulmonary arteries, not from a site in the lungs themselves. So the defining location for DVT is the deep veins of an extremity.