The femoral veins are large blood vessels located in the thigh. They are responsible for carrying deoxygenated blood from the lower limbs back to the heart. The femoral veins run alongside the femoral arteries, which transport oxygen-rich blood to the legs. These veins begin at the knee and ascend through the thigh, eventually merging with other veins to form the external iliac vein. Proper functioning of the femoral veins is crucial for maintaining healthy circulation and preventing conditions like deep vein thrombosis (DVT), where blood clots can form in the veins.