Many therapists, including myself, have been taught to look for patients shoulders shrugging on elevation of the arm and to consider this ‘abnormal’. We are then told to correct or prevent this from happening. The belief is that shrugging of the shoulder is an incorrect, bad, or even a harmful movement pattern and can be a sign that the humeral head is not being held onto the glenoid well due to rotator cuff issues.
The term ‘snugging not shrugging’ is often used by some shoulder gurus to remind us physios that we should focus our attention on reducing this abhorrent movement in our patients, and that the rotator cuff needs attention to snug the humeral head on the glenoid and stop the shrugging to occur. Now, this is a nice catchy phrase and I usually like catchy phrases, however, I think this one, is not a good one…
I actually don’t think there’s anything wrong with a shoulder shrugging on arm movement, especially when someone has shoulder pain and I see it happening a lot. The common assumption is that shrugging occurs due to over-active upper trapezius and weak lower trapezius. This may be possible, however, I think shrugging simply occurs due to global weakness of the whole shoulder girdle in general, or its a strategy to reduce pain on arm elevation.
I often find that when you ask someone with shoulder pain who is shrugging to stop they often feel more pain, so how is this helpful? In fact, when I don’t see a painful shoulder shrugging on elevation I may ask them to try it to try to see if it reduces their pain. If it does then I see nothing wrong with a shoulder shrugging to allow them to move it with less pain for a while..
What also concerns me about this ‘snugging not shrugging’ phrase is that it implies that the humeral head should always be ‘snugged’ and maintained on the centre of the glenoid and that we can assess when this is not happening.
Some physios think they can assess humeral head centring on the glenoid with some archaic clinical tests called the Dynamic Rotatory Stability Test (DRST) and the Dynamic Relocation Test (DRT) as described by Mary Margarey in her 2003 paper here. The tests are described and shown in the photos below from the same paper.
As you can see, during the DRST the examiner attempts to palpate the position of the humeral head in various arm positions to assess for excessive superior, anterior, or posterior movement of it. In the DRT the examiner is palpating to ascertain if the rotator cuff is co-contracting equally without any ‘over-activity’ of the superficial muscles during a humeral distraction and subsequent snugging manoeuvre.
I remember being taught these tests years ago as a keen and eager, but sceptical newly qualified physio, and I remember having the same frustrated and incredulous thoughts and feelings about these tests as I had with all the other motion palpation tests of the spine and SIJ, which I describe in one of my most popular blogs here.
I simply could NOT believe that anyone could actually feel anything close to what was expected. I couldn’t believe anyone could feel the humeral head moving an extra few millimetres under all the soft tissues of the shoulder, or more unbelievably if it was centred on the glenoid or not. Nor did I believe that anyone could feel if the rotator cuff was contracting equally, quickly, or strongly enough.
I persevered with these tests for a while, but like most other joint motion palpation tests elsewhere in the body, I stopped using them years ago, and if I’m being honest I forgot all about them, until recently when this ‘snugging not shrugging’ phrase kept popping up on my courses, with some delegates telling me they are being taught them despite no research on their efficacy, but more importantly their validity or reliability.
However, even without this research the premise of these tests to assess if the humeral head is staying centred on the glenoid during movement is flawed, as the humeral head actually moves around on the glenoid a lot during pain-free, normal movement. There are a number of studies here and here that show the humeral head moves off the anatomical centre of the glenoid usually in a superior-posterior direction in pain-free healthy individuals. In fact, some of these studies show some individuals have up to 12mm of humeral head displacement, which is nearly 25% of the total height of the glenoid.
And this review here on the biomechanics of the glenohumeral joint describes that the rotator cuff and other subacromial structures regularly come into contact with the acromial arch as the humeral head migrates superiorly during normal, healthy, pain-free movement.
So I hope you can see that trying to assess if the humeral head is perfectly centred on the glenoid, is a waste of time, improbable, and unlikely to be happening anyway, even in those without shoulder pain.
The shoulders that I do think have humeral head ‘centring’ issues are usually easy to identify without the need of ‘special’ tests as they often tell you they feel the shoulder is loose or unstable. I do accept that attempting to assess and identify those with more subtle shoulder instability, if this exists can be challenging, but I don’t think tests like these help.
If anything tests like these often make matters worse, confusing therapists and often over diagnosing and worrying patients unnecessarily. As with anything else, the best way to diagnose patients is with a good detailed history, a simple yet thorough examination, and if indicated appropriate imaging.
So, in summary, can we please stop worrying about and demonising the shoulder shrugging on elevation so much. Can we please recognise a shoulder shrug can be a positive adaption to help reduce pain and allow some to move their arm more comfortably, and there is no evidence that this is going to do them any harm. Finally, can we please abandon these ridiculous DRST and DRT motion and muscle palpation tests, as we are now in 2015, not 1995.
As always thanks for reading