Diseased calves with chronic venous disease have more PVs than do healthy calves. IPVs are commonly larger than competent PVs, with most IPVs located in the medial and posterior middle of the calf. Most importantly, the AP-sit method provides a convenient and effective approach for assessing the calf PVs, especially those located in the distal calf, as an alternative or complementary method to traditional manual compression, which is valuable in the daily practice of sonographers.