Through the continuation of the radial artery into the hand as the deep palmar arch and the ulnar artery as the superficial palmar arch, circulation to the hand is usually sufficient to allow the digits to remain viable despite most disease and injury. The superficial arch is complete in almost 80% of hands and incomplete in about 20%. The deep arch is complete in about 98% of hands. The radial artery usually provides most of the flow to three or more digits in 57% of hands, whereas the ulnar artery provides flow to three or more digits in almost 22%. Flow provided from both arteries equally is provided in almost 22%.
