Many of us therapists may remember the days in school when we were first exposed to the scapular dyskinesis test, where we were told to observe for winging or dysrhythmia during arm elevation. We may have been told that the presence of winging or dysrhythmia was related to shoulder pain, but is this really true? Can the mere observation of someone’s scapular movement really give us a clear insight into how that shoulder complex behaves during real-world movement? Does it guide any kind of specific intervention? In the research paper attached, it appears scapular dyskinesis is NOT more prevalent in those with shoulder pain, and may represent normal variability.
At IKN, we view the scapula within the context of a larger network of coordinated segments that offers us a wider insight into the interaction between the upper limb and the midline. From distal to proximal, these segments progress as follows:
Hand → forearm → upper arm → scapular → thorax
A distributed and coordinated coupling should exist between these segments, and this allows the human arm to move in many ways to achieve a wide variety of goals in a diverse range of environments. We’ve also spoken in prior insights about the importance of the hand as the main driver of arm movement, when we consider the control strategies from both a neural and anatomical perspective. It’s easy to step back and say the proximal shoulder complex possesses the greatest amount of musculature compared to the distal arm structures, but this is a purely mechanical way of thinking. Humans are complex systems, and the interaction of neurology and anatomy can never be separated.
Are we saying that observing scapular movement is useless? Absolutely not. It just doesn’t help us paint the full picture. We need to recognize that each “part” or segment of this coordinated linkage has different roles, and working towards gaining a greater appreciation as to what these roles are based on the neurological-muscular-kinematic layout of the arm may help us facilitate much more robust assessments and treatments.
Think of your upper limb like your house. In your house, you have many rooms with different purposes to help you function efficiently. You have your bedroom where you sleep, your bathroom where you wash, your kitchen where you eat etc. Can you imagine if every room was a bathroom? How functional would your home be? Not very. We should possess the same thought process when recognizing the function of specific body regions. There’s a reason your proximal structures like your shoulder have more muscle mass, and why your distal tissues express less. It’s well known that before we move our limb, there will be increased muscle activity of the shoulder tissues to help prepare for movement. This predictive increase in activity helps us manage potential disturbances on our system, and it’s made possible by the presence of extra muscle tissue. Can you imagine if every muscle throughout the limb did the same thing? That wouldn’t be a very adaptable arm.
With this in mind, we should always have a wider focus when assessing individuals with shoulder pain. How might past injuries at the hand or forearm influence the function of the shoulder? Is the individual moving their arm in a way that updates the nervous system about the capabilities of the arm to manage stress well? Are we potentially seeing increased muscular activity at the shoulder because the nervous system doesn’t trust the coordinative capacity of the arm from distal to proximal? These are “big picture” questions of course. To us, these are crucial. Too many therapists narrow their focus on the shoulder, without appreciating its role within the context of other segments. In real world movement, our nervous system takes on a “big picture” role in how it controls our body, so maybe we as therapists should take on this role early in the treatment process too.