Fig. 11-15. Testing finger movements. Upper, If the metacarpophalangeal and proximal interphalangeal joints are stabilized as shown, flexion at the distal interphalangeal joint (flexor profundus) can be tested. Lower, If the metacarpophalangeal joint is stabilized as shown, flexion at the proximal interphalangeal joint (flexor superficialis) can be tested. Click for high resolution image.