Determining patency of palmar arches by retrograde radial pulsation

The patency of palmar arches must be ascertained before radial-artery cannulation is performed. A simple test in which digital pulsation is felt after proximal occlusion of the radial artery has been devised for that purpose. The method is reliable, does not require active patient cooperation, and can be carried out in all clinical situations where the radial artery can be felt.