[Computer tomography determination of the torsion angle of the humerus]

A simple and easy method of CT-measurement of humeral torsion is proposed. This requires a transverse section of the proximal and distal epiphyses. The optimal site of cross-sectioning with reliable construction of the joint axis was determined in ten humeral bones. The variability of the angle was 2 to 3 degrees. Comparing CT-measurements in 50 humeri with anthropometry showed excellent correlation. Varation in humeral torsion on either side was approx. 50 degrees with the same mean value in right and left humeri of our specimens. Deviations in bone positioning within the gantry of up to 15 degrees in two different planes had little effect on the measurements. Habitual dislocation of the shoulder as well as assessment of postfractural malrotation of the humerus might be indications for measurement of humeral torsion.