[Carpo-metacarpal flexion of the thumb in healthy adults].

Metacarpophalangeal flexion of the thumb is known to be highly variable. To obtain normative values, active metacarpophalangeal flexion of the thumb was measured bilaterally in healthy Caucasian adults (female n = 403; male n = 366) in a standardized manner. Independent of gender, inter-individual variation was high, ranging between 16 degrees and 90 degrees and showing a continuous decrease with increasing age. Women showed a bigger range of motion than men but in both range of motion was higher on the left thumb (mean 1.4 degrees in women and mean 1.1 degrees in men). No influence of hand dominance was observed. Thus, the healthy contralateral side should be used as parameter of comparison.