Key Point

• Identifying the variations of scapular dyskinesis can lead to the right treatment for shoulder impairment or pain.

Shoulder disorders are diverse and a primary reason why clients might seek soft-tissue therapy. Movement at the shoulder is complex, so when this movement is impaired, it can cause clients significant pain. One such condition is scapular dyskinesis or dyskinesia (SD), which is essentially the faulty movement and position of the scapula. There are several causes of this movement dysfunction.

Let’s look at the anatomy and function of the shoulder and how intricate movement patterns are related to pain complaints in the shoulder region. 

Anatomical and Biomechanical Review

Several shoulder structures play a role in SD. First are the three major bones of the shoulder complex: the scapula, humerus, and clavicle. The ribs are also involved in shoulder movement, but their role is indirect in this condition because they have little movement. However, they anchor the serratus anterior muscle, which we will explore below. 

Close to 20 muscles are attached to the scapula, so the muscle can get pulled simultaneously from multiple directions. Of these numerous muscles, the most important concerning SD are the upper trapezius, rhomboids, and serratus anterior (Image 1). They produce the most significant forces for upward scapular rotation. We’ll see more about how they work together in the biomechanics section. 

The glenohumeral joint capsule is critically important in guiding and limiting movement at the glenohumeral joint. Restrictions or adhesions in the joint capsule can significantly impact scapular mechanics and often contribute to SD. Other internal injuries can also alter proper scapular mechanics, such as glenoid labrum injuries, adhesive capsulitis, ligament sprains, subacromial impingement, and biceps tendon disorder. 

The primary shoulder joint is the glenohumeral, which has the greatest range of motion of any joint in our body. However, four joints make up the entire shoulder complex: the glenohumeral (between the scapula and humerus), acromioclavicular (between the scapula and clavicle), sternoclavicular (between the sternum and clavicle), and scapulothoracic (between the scapula and the rib cage). The scapulothoracic articulation is not a true joint because it doesn’t have a joint capsule or other features of synovial joints, but it plays a crucial role in SD. 

The most significant motion problems in SD are flexion and abduction of the shoulder. A look at shoulder abduction illustrates the critical importance of scapular mechanics and the primary issues arising from SD. When you lift your arm into full abduction, most of that motion occurs at the glenohumeral joint. However, the scapula also moves upward and tilts that glenoid fossa up so the humerus can fully abduct. 

A biomechanical principle called force couple helps create this upward rotation of the scapula. It is a coordinated movement pattern between the upper trapezius and the serratus anterior muscles (Image 2). The upper trapezius pulls the distal and upper margin of the scapula superiorly, while the serratus anterior hooks the scapula from the lower and medial side to pull it into upward rotation. 

During shoulder abduction, another coordinated motion pattern, the scapulohumeral rhythm, also involves the scapulothoracic articulation and glenohumeral joint. There is roughly a 2:1 ratio of glenohumeral to scapulothoracic movement—for every three degrees of shoulder abduction, two happen at the glenohumeral joint and one at the scapulothoracic articulation (Image 3). An altered scapulohumeral rhythm is often the root of many SD issues. But first, let’s more clearly define the categories of scapular dyskinesis and look at some of the main contributing factors. 

Variations of Scapular Dyskinesia

Scapular dyskinesis is divided into three categories. The first is shoulder-related and includes altered scapular movements that result from shoulder pathology. Common examples include acromioclavicular joint injury, rotator cuff injury, and subacromial impingement, labral injuries, nerve injury, and clavicular fracture. 

The second category is neck related. Most neck pain from SD is considered mechanical because it usually results from excess compression or tension on structures in the neck or shoulder region. An example would be altered neck and shoulder movement that adversely affects facet joints. Ligament injury or referred pain from myofascial trigger points are other examples of mechanical neck pain that may result from altered shoulder movement. 

Posture-related issues, the third category, include conditions such as upper thoracic kyphosis or excessive cervical lordosis, which impair shoulder mechanics. For example, in an upper thoracic kyphosis, the scapula is more protracted (sliding around the rib cage anteriorly) as the upper thoracic region slumps forward. This altered position increases the likelihood of dysfunctional mechanics in shoulder movements. 

Let’s look at how some of these problems cause altered scapular mechanics and what else may result from those impaired movement patterns. 

Several potential shoulder and neck problems can contribute to SD. Rotator cuff pathology, glenohumeral instability, acromioclavicular joint injury (known more commonly as a shoulder separation), and labral tears impact tissues of the shoulder region and can prevent the shoulder from operating with its optimal and necessary mechanics. With many of these conditions, pain avoidance causes the person to compensate and use altered movement patterns (one category of SD). Using these altered movement patterns can lead to further shoulder pain and disability. 

Nerve compression or tension injuries are key issues in many SD conditions. Several nerves of the shoulder region play a significant role in these problems. The dorsal scapular nerve innervates the rhomboid muscles, and when it is injured or dysfunctional, the rhomboids cannot play their critical role in scapular mechanics. Earlier, I mentioned the importance of the force couple between the upper trapezius and the serratus anterior. The rhomboids also play a role in that force couple, but their contribution is not as significant based on their angle of pull. 

Other nerve involvement in SD includes the spinal accessory nerve that innervates the upper trapezius and the long thoracic nerve that innervates the serratus anterior muscle. These two nerves are the most important when evaluating impaired motor patterns of SD. The long thoracic nerve plays a more significant role in SD, so let’s observe its function. 

Conditions like thoracic outlet syndrome or cervical disc pathology can put adverse pressure on the long thoracic nerve or its roots and impair motor activity to the serratus anterior. Mechanical nerve compression may also occur from outside forces, such as wearing a heavy backpack or equipment bag carried over the shoulder. 

Compressed motor nerves cause weakness and atrophy. Evidence of weakness in the serratus anterior muscle from long thoracic nerve compression presents when our clients are prone on the treatment table. Serratus anterior weakness produces the postural alteration called winged scapula. In this postural distortion, the medial border of the scapula lifts off the rib cage and appears as if it is pulling away from the rib cage. It is the serratus anterior that holds the scapula close to the ribs. 

If you recall from our discussion about the scapulohumeral rhythm, the serratus anterior pulls the scapula into upward rotation during shoulder abduction. When the serratus anterior weakens, the scapula isn’t pulled into upward rotation as effectively. If the distal end of the scapula (near the acromion process) doesn’t get lifted during abduction, the humerus and other tissues underneath the acromion process of the scapula may get pinched under that bony shelf. Consequently, the dysfunctional movement caused by the nerve pathology (producing serratus anterior weakness) may create another problem, like shoulder impingement. 

Assessing Scapular Dyskinesis

The primary problems in SD are dysfunctional movement patterns. So, the usual assessment is a physical exam that looks at motion during the primary single-plane shoulder movements. The practitioner looks for any disturbance in smooth, even movement or limitations in range of motion. Pay particular attention to the scapulohumeral rhythm during active abduction and look for compensation or difficulties moving through the full range of motion. 

Comparing active and passive movements can be insightful in assessing movement problems that might be caused by SD. In active movements, the client performs the motion independently without the therapist’s assistance. Active movements often reveal difficulties due to impaired motor coordination. If the muscles are not coordinating properly, the movement may appear erratic, or the person may not be able to complete a full range of motion. These motion challenges are most evident in active abduction or flexion. 

The movement limitation may or may not be painful, so your observation of smooth and coordinated movement is essential. Additionally, evaluating the client in various positions, such as lying down versus standing, engages different muscle groups. This change in positioning can enable movements that might be difficult or impossible in the standard upright stance.

In contrast, passive movements are where the practitioner moves the client’s limbs without any participation by the client. Because there is no requirement for motor coordination in passive movement, a motion limitation or poor coordination that appeared in active movement will often not appear in the same movement when performed passively. 

Shoulder pain may come from damaged internal structures, such as the labrum or joint capsule. So, the lack of coordinated movement during shoulder motions may be more about pain avoidance than pathologies such as nerve compression. There may be movement or coordination problems that occur with or without pain.

The goal of palpation in the assessment is not so much to feel tightness or problems in a specific tissue but more about feeling the motion of the underlying bones during movement. The practitioner places their hand over the client’s scapula, then watches and feels for how well coordinated the scapular movement is, especially during flexion or abduction. It’s beneficial to compare the movement pattern with the opposite side, as long as there is no similar problem on the opposite side. 

Treatment Strategies for Scapular Dyskinesia

Treatment strategies for SD initially focus on structural factors that cause pain avoidance. If an internal joint structure is at fault, such as the labrum or joint capsule, tissue involvement should be addressed first. Then, attention can focus on restoring proper movement patterns and reestablishing proper coordination. An accurate evaluation by another health-care professional is recommended to identify any structural issues involved. 

In many cases, rehabilitative exercises with a physical therapist address the dysfunctional motor patterns. When exercise is a primary treatment strategy, ensure proper movement patterns are used in the strengthening exercises. Reinforcing dysfunctional movement patterns can cause further problems. Stretching and other flexibility exercises are also commonly a part of this strategy. 

Although there is little research on massage treatment in SD, massage therapy still has a role in treatment. As with stretching, massage can be quite helpful in reducing hypertonicity in affected muscles and helps restore proper biomechanical balance around affected joints. Massage also reduces general pain and increases comfort in the body. 

Massage and soft-tissue treatment strategies that employ neurological engagement during the treatment are beneficial. Modalities such as facilitated stretching, often called proprioceptive neuromuscular facilitation (PNF) or muscle energy technique (MET), use active muscle contraction and stretching or soft-tissue mobilization. 

Different techniques, including active engagement methods, involve contracting muscles actively while applying a soft-tissue treatment (Image 4). These approaches are especially effective in improving proprioception, directing the brain’s focus to the areas engaged in movement. Such active neurological methods are especially beneficial when issues stem from neurological coordination. Additionally, increasing the range of motion is an important aspect. Direct manipulation of soft tissues provides a wealth of sensory feedback to the central nervous system. This influx of sensory information plays a crucial role in reestablishing correct neuromuscular coordination in SD.

Conclusion

A comprehensive understanding of scapular movement and its potential issues will help you deliver precise and effective treatment to improve your client’s range of motion and help address SD. It’s essential to acknowledge that sometimes the most beneficial course of action may involve referring the client to another specialist. Recognizing dysfunctional scapular movement patterns enables you to offer the most suitable treatment or guide them to the right practitioner for optimal results. In both scenarios, you are fulfilling the client’s health-care needs, demonstrating your commitment to thoroughly assessing their condition, and providing valuable advice. Effective treatment options, such as the mentioned massage therapies, will help relieve your client’s pain and dysfunction.