This is an arterial arcade that lies superficial to everything in the palmar compartment, i.e. in contact with the deep surface of the palmar aponeurosis. It is formed by the direct continuation of the ulnar artery beyond the flexor retinaculum but it is badly named, for in two-thirds of hands it has a hockey-stick shape and is not a complete arch. If it is complete it becomes continuous with the superficial palmar branch of the radial artery. This branch may pass superficial to or through the thenar muscles. The arch lies across the center of the palm, level with the distal border of the outstretched thumb web. From its convexity a palmar digital artery passes to the ulnar side of the little finger, and three common palmar digital arteries run distally to the webs between the fingers where each vessel divides into proper palmar digital arteries that supply adjacent fingers. The thumb side of the index finger and the thumb itself are not supplied from the superficial arch since they receive branches from the radial artery.