Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Deep Vein Thrombosis ?
    ### Response:
    Espaol
                
Deep vein thrombosis (throm-BO-sis), or DVT, is a blood clot that forms in a vein deep in the body. Blood clots occur when blood thickens and clumps together.
                
Most deep vein blood clots occur in the lower leg or thigh.
    