Maximum Palmar Abduction Angle of the Trapeziometacarpal Joint in Healthy Subjects Can Be Evaluated Accurately Using a Radiograph-Based Measurement Technique.

In carpal tunnel syndrome, the abductor pollicis brevis, which is the primary muscle for the palmar abduction of the thumb, is almost inevitably impaired. The active palmar abduction of the thumb may be a better indicator of thumb disability. The authors aimed to establish a simple and accurate method to measure the angle of active palmar abduction of the thumb and to determine the maximum angle values in healthy women.