Fig. 1.

Independent flexor digitorum superficialis function, examined by both the expanded and our new tests. (A) Bilateral palms and corresponding fingers are held facing each other in our new method. (B) The little fingers can touch the dorsal sides of both hands, with the proximal interphalangeal (PIP) joints flexed and the distal interphalangeal (DIP) joints extended in our new method. No gap between the ring fingers is seen. (C) The little fingers flex the PIP joint without DIP flexion by the expanded test.