Dynamic Scapular Stability

By Meggie Morley, DPT Student

A solid foundation of scapular stability is not only important for optimizing shoulder mechanics, but also the motions of the elbow, wrist, and hand. There are traditional methods of assessing and treating scapular stability, but several articles and studies are exploring new ideas and approaches. In an article by McQuade et al, scapular stability was defined as “’normal’ scapula movement on the thorax during upper extremity motions.”

One of the core principles of scapular motion is the concept of scapulohumeral rhythm. The idea is that for every two degrees of humeral elevation there is a corresponding one degree of motion of the scapula. For example, 180 degrees of shoulder abduction is comprised of 120 degrees of arm elevation and 60 degrees of scapular upward rotation. However, recent studies have shown that scapulohumeral rhythm can actually vary from anywhere between a 1:1 to a 6:1 ratio. Several factors such as external load, speed, fatigue, pain, and plain of elevation of the arm where all shown to affect scapulohumeral rhythm.

Traditional treatment methods have also tended to focus on identifying postural “abnormalities” in the scapula and correcting them through strengthening and stretching. However, a systematic review by Ratcliffe et al. studied patterns in subacromial impingement, and found that no ideal scapula position exists and deviations in scapula motion do not cause or contribute to subacromial impingement. They found that there was evidence for scapula kinematic alterations in people with impingement, but the type and prevalence of those alterations were inconsistent. In other words, one person could present with the same kind of movement pattern and static scapular posture as the next person, but one could have impingement and the other could show no symptoms at all.

After taking these new studies into account there are several ways to optimize scapular mobility and stability for each individual patient. Regardless of the individual’s scapular posture or movement patterns, it is critical that the scapular stabilizers and upward rotators are properly firing before moving the upper extremity, specifically the trapezius and serratus anterior muscles. Warming up the scapular stabilizers before a shoulder workout is important in order to ensure that the scapula will be optimally supporting the upper extremity. Single Arm Plank variations are activities that require the scapular muscles of the stabilizing arm to activate in order to keep the rest of the body steady.

It is also important to train the muscles in the range of motion that is weak or required for certain sports and activities. This is demonstrated in the Isometric Band Hold + Rhythmic Stabilization drill. Demand is put on the stabilizing muscles of the scapula and core by holding the band steady as the practitioner attempts to move the arm out of position.

The concept of dynamic scapular stability is continuing to evolve as more studies are published. A focus on optimal scapular stability and mobility with an attention to each patient’s individuals needs is one way to incorporate both new and traditional treatment methods in order to achieve the patient’s goals.

FullSizeRender 9 Blog Post written by Meggie Morley, DPT Student at Columbia University. Meggie is currently in her final Clinical Rotation with me at Catz Physical Therapy Institute.