After months of shoulder pain, our 17-year old son was finally diagnosed with something called scapular dyskinesia. We think this may keep him from having surgery as it looks like exercise and sports taping will do the trick. So, can you explain just exactly what is scapular dyskinesia? I know the scapula is the shoulder blade and that about the full extent of my understanding.

Abnormal motion of the scapula is called scapular dyskinesia. You have a good start in your knowledge because the anatomy and relationship of bones and muscles in the shoulder complex is the key to understanding scapular dyskinesia.

The scapula (your shoulder blade) moves in a rhythm with the shoulder joint. As the arm raises overhead, the scapula slides and rotates in a 2:1 ratio with the shoulder. For every two degrees of motion in the shoulder joint, the scapula moves one degree. This is called the scapulohumeral rhythm.

Scapular dyskinesia can be observed visually. As the athlete moves his or her arm out to the side and up overhead, the scapula doesn’t glide and tilt smoothly like it should. Since most of the shoulder muscles attach to the scapula and the shoulder socket is part of the scapula, that means scapular dyskinesia affects shoulder motion as well.

Athletes (especially throwing athletes) report pain, stiffness, and impingement during shoulder movement. Impingement refers to the soft tissue around the shoulder getting pinched during certain movements. Anyone can develop scapular dyskinesia (not just throwing athletes) but the reasons for this are not always clear. Usually overuse (repetitive motions) or injury of the shoulder results in muscular imbalance that contributes to the problem.