Medical Musings, Health Hypotheses & Therapeutic Thoughts
Shoulder pain is pretty common, with only the back and the knee giving more of us grief (1,2). It can also be stubborn. According to the British Medical Journal and the British Journal of General Practice, only about 50% of new episodes of shoulder pain presenting to medical doctors show a complete recovery after six months (3,4), After a year, that figure has only risen to 60% (5)!
So why is it that the shoulder causes so many - and seemingly such persistent - issues?
Largely, it is because the shoulder itself is a very complex bit of kit, with a lot of interactions with the structures around it.
The "shoulder joint" is actually a constellation of several joints (see figure below):
(1) the scapulothoracic joint , which is not a true joint at all, but rather the interface, or articulation, between the shoulder blade and the rest of the thoracic cage (mid back and ribs).
(2) the glenohumeral joint , which is the shoulder joint proper (the ball-and-socket, although it's more like a ball-and-tiny-saucer).
(3) the acromioclavicular joint between the bony bit at the end of your shoulder and your collarbone,
(4) the sternoclavicular joint, between the collarbone and breastbone. This is the only bony connection point between the arm and the rest of the skeleton - everything else is controlled by muscles!
In order for your shoulder to do its job, all of these must be working well - and together. The shoulder is incredibly mobile, but to get as much movement as it has, there has to be a trade-off - stability. Because it is unstable, the shoulder relies on a complex balance of muscles around it to function (in an upcoming blog I will talking about a particularly important group of these, the rotator cuff).
The diagram below is culled from some of my old student notes, and should give some idea of the complexity of the muscles that act on and around the shoulder, as well as further down the arm.
On that note, it is also important to remember that the shoulder does not exist in isolation, but is the attachment point to the rest of the body for your arm, elbow, forearm, wrist and hand.
As an (ex-)anthropologist, I could wax lyrical on the majesty and intricacy of all the thingummybobs and anatomical wonders that make your arms - and most importantly, hands - the marvels of nature that they are. Opposable thumbs, baby, they're what make us unique. But I digress...*
So the presence of the rest of the upper limb complicates things a bit. The body is a master at compensation, and, if things are going wrong down at the coalface (for example, the hand and wrist), it will quite happily sacrifice anything up the chain to maintain that wonderful hand and wrist mobility.
So, hand, wrist and elbow problems can also cause shoulder issues.
Likewise, as we touched on briefly in the last shoulder blog) other common contributors to shoulder pain include the neck, thoracic spine (mid-back) and ribs.
The viscera (internal organs; heart, lungs, liver, stomach etc.) or neurological issues (such as stroke etc.) can also give rise to pain in the shoulder. This is why it is important to have your shoulder pain checked out by a trained professional.
So, in short, there is a lot going on. All the different forces from the arm, your trunk and ribs (including breathing) as well as head and neck are meeting in this area and interacting, so it is no surprise that so many shoulder issues remain unresolved.
If you just look at the shoulder in isolation, instead of also looking at these related areas in the rest of the body, you can often miss these crucial predisposing and maintaining factors (vulnerabilities that helped your problem develop, and issues that are preventing your recovery).
Your osteopath is trained to examine and assess each of these components and how they relate to each other, and will treat as many of them as possible. In this way, even if some underlying damage is present, the body’s ability to compensate and cope will allow normal function.
Specific shoulder issues are presented in our next blog on the rotator cuff. Also stay tuned for further upcoming blogs on other shoulder issues e.g., bursitis, frozen shoulder.
*if you are interested in this sort of thing, start with Evolution of the human hand: the role of throwing and clubbing, and follow the references from there....!
4, Picavet HS, Schouten JS. Musculoskeletal pain in the Netherlands: prevalences, consequences and risk groups, the DMC(3)-study. Pain 2003;102:167–78
5. Urwin M, Symmons D, Allison T, Brammah T, Busby H, Roxby M, Simmons A, Williams G. Estimating the burden of musculoskeletal disorders in the community: the comparative prevalence of symptoms at different anatomical sites, and the relation to social deprivation. Ann Rheum Dis 1998;57:649–55.
1. P. Croft, D. Pope, A. Silman, The clinical course of shoulder pain: prospective cohort study in primary carePrimary Care Rheumatology Society Shoulder Study Group. Br Med J 19963136012
2. D. A. Van der Windt, B. W. Koes, A. J. Boeke, W. Deville, BA Bouter. L. M. De Jong, Shoulder disorders in general practice: prognostic indicators of outcome. Br J Gen Pract 19964651923
3. D. A. Van der Windt, B. W. Koes, A. J. Boeke, W. Deville, BA Bouter. L. M. De Jong, Shoulder disorders in general practice: prognostic indicators of outcome. Br J Gen Pract 19964651923