Fig. 2.

Showing a connection of the flexor digitorum superficialis (FDS) between the little and ring fingers of the right hand by the expanded and our new tests. (A) Examination by the expanded test shows slight flexion at the proximal interphalangeal (PIP) joint, unless (B) releasing of the ring finger allows PIP joint of the little finger flexion. (C) Our new examination test shows when the two ring fingers keep straight and maintain closely touched, difficulty in flexing the PIP joint of the little finger to touch the target. (D) Mild flexion of the PIP joint of the adjacent ring finger was recorded as the loose FDS connection between the little and ring fingers in our new test.