Distribution of subbranches of palmar cutaneous branches of median (PCBm) and ulnar (PCBu) nerves. Du, Distance from origin of palmar cutaneous branch of ulnar nerve to thenar crease (mean 23 mm); Dm, distance from terminal end of most ulnar subbranch of palmar cutaneous branch of median nerve to thenar crease (mean 12 mm); Dr, distance from terminal end of most radial subbranch of palmar cutaneous branch of median nerve to thenar crease (mean 5 mm).