The superficial palmar arch is formed predominantly by the ulnar artery, with a contribution from the superficial palmar branch of the radial artery. However, in some individuals the contribution from the radial artery might be absent, and instead anastomoses with either the princeps pollicis artery, the radialis indicis artery, or the median artery, the former two of which are branches from the radial artery. Alternative names for this arterial arch are: superficial volar arch, superficial ulnar arch, arcus palmaris superficialis, or arcus volaris superficialis. The arch passes across the palm in a curve (Boeckel's line) with its convexity downward, With the thumb fully extended, the superficial palmar arch would lie approximately 1 cm from a line drawn between the first web space to the hook of hamate (Kaplan's cardinal line)...