DVT most commonly affects the veins in the lower extremities, producing venous insufficiency. DVT is often divided into two types –Below-the-knee DVT, the more common type, begins in the deep veins of the calf –Ileofemoral DVT, the less common type, is associated with direct venous wall injury, usually as a result of hip or knee surgery or induced by a central venous catheter - Although far less common, upper extremity DVT does occur, most often following central venous catheter placement