Abstract
Dear Sir,
I read the paper by Shaaban et al. (2008) on the effect of elbow position on the range of supination and pronation of the forearm with interest. Establishing the normal range is certainly important when assessing pathology. It is well known that clinical measurement of forearm rotation is often inaccurate, a reasonable quick technique being to make measurements at 90 degrees of elbow flexion with the arm held against the trunk to eliminate shoulder rotation (Sibinski et al., 2007). The finding by Shaaban et al. (2008) of increasing supination with increasing flexion of the elbow fits with simple observation. However, the finding of more pronation in extension, with 110 degrees at full extension, does not.
I am concerned that the measurements do not appear to be referenced to fixed bony points, e.g. Epicondyles of the humerus. Although the upper arm was stabilised with a pneumatic cuff this may not completely eliminate shoulder rotation. The carrying angle of the elbow and range of external rotation of the shoulder is such that, when the elbow is fully extended, shoulder external rotation and hence more supination is unlikely. However, internal rotation and hence more pronation is likely and could explain the amount of pronation observed with the elbow extended. I would suggest that this is a potential limitation of the accuracy of the study.