[Fascicular arrangement of the intrinsic muscles of the thumb].

The authors had realised the dissections of 30 thenar eminens with the help of optical magnifying. Its intrinsic muscles of the thumb involves several fascicles with a special insertion and innervation which their confer an accurate function. They are divided in two levels. The dorsal fascicles act on the dorsi flexion of the thumb, the palmar fascicles on the palmar flexion. The fascicles of a muscle run side by side, but the ones of the dorsal level of the adductor are intersected.