What is a DVT?
Deep vein thrombosis (DVT) is a blood clot that forms most commonly in the deep veins of the leg. Clinically significant DVTs are any clot in the popliteal vein (vein behind the knee) and higher up. Causes of DVT are trauma, prolonged stasis (immobility usually related to disease or injury) or a hypercoagulable (prone to forming clot) disorder. They are common after trauma especially with long bone fractures. Most commonly they will cause discomfort and acute leg swelling (in the involved leg only). They can also present with pulmonary embolus. With PE, the clot breaks off and migrates through the heart into the lungs blocking blood flow to certain portions of the lung. This can be a life threatening even fatal event depending on the size of the clot.
Below is an example of a DVT in the popliteal vein documented by US.