Normal compressibility of the lower limb veins:

The above 2 Doppler images show the normal superficial femoral vein (Left) and the Normal popliteal vein (Right). Compression of the veins by the Doppler probe causes the normal veins to collapse COMPLETELY (compressibility). Presence of thrombus would cause poor or absent compression of the vessels. Note that the arterial flow is not hampered by the probe pressure. However, the veins disappear in the right half of each image.

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