Which arteries are typically used to obtain ankle systolic pressure for ABI?

• A. Dorsalis pedis or posterior tibial arteries
• B. Femoral or popliteal arteries
• C. Carotid or vertebral arteries
• D. Radial or ulnar arteries

Answer: (A)

Ankle pressures for the ABI come from arteries that actually supply the foot, because the test compares that distal pressure to the arm’s brachial pressure to assess leg perfusion. The typical sites are the dorsalis pedis artery on the top of the foot and the posterior tibial artery just behind the medial malleolus. These arteries are easy to access with a Doppler and give a reliable measure of the ankle systolic pressure. If one site isn’t detectable due to disease, the other can be used. Arteries higher up, like the femoral or popliteal, would measure proximal pressures and aren’t used for the standard ankle measurement. Carotid/vertebral and radial/ulnar arteries are in the neck or upper limb and not relevant for this ankle-focused test.