In assessing ankle pressures, which vessel's pressure is used to calculate the ankle/brachial index when multiple pressures are taken?

When calculating the ankle/brachial index (ABI), the pressure in the dorsalis pedis artery is typically used along with the brachial artery pressure. The ABI is a significant vascular diagnostic test that measures the ratio of the blood pressure in the ankle to the blood pressure in the arm, helping to assess peripheral artery disease.

The dorsalis pedis artery is one of the primary blood supply pathways to the foot and, when assessing for vascular health, provides a reliable measure of blood flow. It's often preferred due to its accessibility and consistency in being palpable in the general population.

While other arteries like the posterior tibial artery can also be used, the dorsalis pedis is most frequently chosen in ABI calculations because it can provide accurate readings of perfusion in the anterior and lateral aspects of the foot. This helps clinicians in diagnosing potential issues related to blood supply to the lower limbs. Other choices, such as the peroneal artery, anterior tibial artery, or sural artery, are less commonly involved in the standard ABI calculation, making the dorsalis pedis artery the critical vessel in this context.