The arteries have been filled with thorotrast. Two variations from the commonly described arrangement of the vessels are to be noted. (A) The a. volaris indicis radialis is absent. A branch of the first dorsal metacarpal artery (3, upper pointer) supplies the area normally reached by this vessel. (B)The superficial volar branch (7) of the radial artery does not enter into the formation of the superficial volar arch (16). This latter situation occurs frequently.