Bilateral Congenitally Absent Trapezius Musculature and Anomalous Scapuloclavicular Accessory Muscle: A Case Report.

CASE: An otherwise healthy 10-year-old boy presented with severe bilateral shoulder dysfunction because of lateral scapular winging. He underwent bilateral modified Eden-Lange tendon transfers, resulting in near-normal restoration of shoulder range of motion at the 1-year follow-up. Intraoperatively, he was found to have bilateral absent trapezial muscles and an anomalous scapuloclavicular muscle spanning from the superomedial scapula to the posterolateral clavicle.

CONCLUSION

This case represents the only known report of bilateral absent trapezius muscles without involvement of other trunk musculature or congenital abnormalities. In addition, the patient exhibited a previously unidentified anomalous muscle.