Which of the following is TRUE regarding the level of the superficial palmar arch?

The convexity of the superficial palmar arch is approximately at the level of a line drawn across the hand from the distal border of the extended thumb. The superficial palmar arch, which is the main termination of the ulnar aery, is completed on the radial side in a variable manner, e.g., by the radialis indicis.The arch lies on the flexor tendons and the branches of the median nerve, under cover of the palmar aponeurosis. It gives off several palmar digital aeries.