In order to test the opposition and the counter-opposition (reposition) of the thumb, the method proposed here does not require the measuring of angles; rather, the hand itself is used as the system of reference. The opposition test consists of touching the four long fingers with the tip of the thumb: the score is 1 for the lateral side of the second phalanx of the index finger, 2 for the lateral side of the third phalanx, 3 for the tip of the index finger, 4 for the tip of the middle finger, 5 for the ring finger and 6 for the little finger. Then, moving the thumb proximally along the volar aspect of the little finger, the score is 7 when it touches the DIP crease, 8 on the PIP crease, 9 on the proximal crease of the little finger and 10 when it reaches the distal volar crease of the hand. This test is valid only if the first stages are possible: a crawling thumb in the palm is not an opposition motion. The counter-opposition test (or reposition test) needs the other hand as a reference system. The hand to be tested is set upon the table palm-down while; the other hand is laid on the table on its medial side, close to the tip of the first hand thumb; now this thumb is actively drawn up as high as possible.(ABSTRACT TRUNCATED AT 250 WORDS)