Scapular Dyskinesis in Athletes

The scapula plays multiple key roles in producing normal shoulder and arm function in the overhead throwing motion. Its positions and motions are created and controlled by coordinated patterns of muscle activations and synchronised trunk and arm motions, and are also controlled and constrained by key skeletal components (the clavicle, acromioclavicular and sternoclavicular joints). This creates a stable base for muscle activation, precise glenohumeral concavity/compression ball and socket kinematics throughout the arm motion, optimal force and energy transfer from the core to the hand, and efficient work through the system of the shoulder, arm, and hand. However, dysfunction of the scapula can negatively affect scapular stability, glenohumeral joint stability, and the ability to transfer energy. Scapular dysfunction occurs as the result of anatomic injury, suboptimal physiology, and/or altered biomechanics. This chapter provides current concepts of clinical understanding of scapular function and dysfunction in athletes and discusses preferred methods of evaluation and management of the dysfunction.