Abstract
[Purpose] The purpose of this study was to evaluate the characteristics of the range of shoulder rotation in humeral retroversion in a disabled throwing shoulder. [Subjects] The subjects were 38 male pitchers with disabled throwing shoulders. [Methods] Using ultrasound, we measured and compared the range of shoulder rotation, and the influence of humeral retroversion on the pitching and non-pitching sides. [Results] The pitching side average humeral retroversion was 11 degrees greater than that of the non-pitching side. The pitching side had an average external rotation angle that was 9 degrees greater than that of the non-pitching side, the inner rotation angle showed an average decrease of 18 degrees, and total arc showed an average decrease of 9 degrees. All the differences were significant. [Conclusion] These results suggest that range of shoulder rotation in a disabled throwing shoulder is influenced by the boniness of humeral retroversion, and the shoulder soft-parts organization nature.
