Mid-Week MOT: Shouldering the blame - Part One
Shoulder pain...........there are many causes, from tendonitis to dislocation. I will cover as many as I can over the next couple of weeks and hope to simplify this complicated joint and all its perculiarities!
Lets start with the muscles that hold the shoulder together, the rotator cuff muscles. The long arm bone, humerus, is held within the shallow socket of the shoulder blade/scapula by several strong ligaments to ensure good stability whilst still maintaining maximum mobility. The rotator cuff muscles, or four muskateers, which act on that joint are named as follows:
Supraspinatus, Infraspinatus, Teres minor and Subscapularis.
Subscapularis is the odd one out as it sits on the front of the scapula sandwiched against the ribs. It helps to turn the arm inwards, thumbs down. The others are all on the back and top of the scapula and are involved in lifting the arm and turning it out (thumbs up position). See the pic below to get an idea of the anatomy of this joint and the position of the rotator cuff (RC).
As you can see, sitting on top of the end of supraspinatus is a bursa or pad filled with cushioning fluid. You can imagine that if the bursa becomes unhappy (bursitis) how it could impinge on the muscle and cause pain during movements such as raising the arm. This can irritate the tendon of supraspinatus as it butts up against the bony acromion causing impingement and tendonitis.
If this does not resolve quickly enough then the body sends in calcium to strengthen the tendon and we have calcific tendonitis, which is much harder to treat.
The supraspinatus tendon is the most commonly injured of the RC due to its close proximity to the bony acromion process of the scapula and its dynamic action of lifting the arm through the first 60 degrees of elevation.
The RC muscles can also suffer from tears and over strain just like any other muscle. This can result in pain and stiffness and loss of full range of movement for a period of time.
As well as lifting the arm, and rotating it, the RC's primary function is to pull the head of the humerus into the socket (glenoid cavity), holding it down so that it does not rub on the scapula and collarbone/clavicle framework above during elevation movements.
Rotator cuff dysfunction can give you pain that goes from your neck all the way down to the elbow and is often misdiagnosed and under-treated. It is important to get a thorough assessment of your shoulder, ribs, neck, elbow and upper back if you have shoulder pain, to rule out problems with those structures that surround this joint. This examination should also rule out any pain coming from the heart or lungs.
As you can see in this diagram of the shoulder, it is made up of the main humerus and scapula joint (glenohumeral/GH) and also the acromioclavicular joint (AC) where the top of the scapula meets the clavicle.
The AC is a very small joint doing a very big job and often buckles under the strain of a poorly functioning shoulder.
This joint allows greater movement at the shoulder by engaging the clavicle and pivoting the arm to allow a "hike" so that you can reach up higher and climb to get out of danger - well thats if you are being chased by a bear!!!
The AC joint can be damaged by repeated movements such as heavy bench or military pressing and also by falls onto an outstretched hand or by landing on it directly. Pain can spread throughout the shoulder and up to the neck. Movements such as reaching across the body or rubbing the hands together are particularly painful. If the ligaments are sufficiently disrupted then you can feel a step at that joint where the clavicle has been allowed to rise up and stick out. The degree of 'steppage' is a good indicator of the level of damage to the joint. The problem generally resolves over time but can require surgical treatment. Bony growth called spurs, under the joint can snag on the supraspinatus tendon and require shaving down (surgical decompression).
Good manual therapy, thermal treatment from ice or heat, mobilisation and active rest are all required at various times during these injuries. Osteopathy can be very helpful in treating the shoulder and its surrounding structures.
Next time we will look at frozen shoulder and problems with the biceps tendon.
As always, for osteopathy in High Wycombe and beyond, call Lucy from OsteoFusion on 07833 321604 or email firstname.lastname@example.org
Thanks for reading.