19 May What’s wrong with my shoulder?
Shoulder pain is very common – it is the third most common musculoskeletal complaint presenting to primary care and about one in seven patients will still require ongoing treatment after 3 years. The shoulder is one of the most complex and most mobile joints in the body.
There are many causes of pain that are felt in the shoulder region including both local shoulder injuries as well as pains that are referred from other parts of the body. Pain that spreads to another area is called referred pain. Common sites of pain spreading to the shoulder include the neck and less commonly from irritation of the diaphragm such as gall bladder pain. This phenomenon of referred pain comes about because nerves from the same spinal segments that supply the shoulder also have branches that innervate other structures. Our brains are not so good at differentiating pains arising from deep in the body.
This diagram shows the common patterns of referred pain arising from some of the facet joints in the neck. Pains felt over the top of the shoulder or over the back of the shoulder blade are not usually due to shoulder pathology – they more commonly are spread or referred from the deeper joints or muscles in the neck.
Clues as to the cause of the pain may be found in description of how the pain started – was it a single traumatic event such as a fall onto the shoulder, or did it just come on slowly? Does it hurt to sleep on that side in bed? Or does it hurt only when raising the arm overhead? Where is the pain? The following diagram shows the locations of the more common local causes of local shoulder pain.
Some pains are very localised such as the Acromio-clavicular Joint pain ( A-C joint = joining the collar bone to the shoulder blade). Sprains of that joint are common in sport after a side bump to the shoulder and in older people osteoarthritis may develop, causing pain and clicking in the joint. Other pains are often felt more deeply and over a wider area such as a frozen shoulder where the shoulder slowly stiffens over a long period of weeks or months. Probably the most common complaint is impingement. Pain is felt laterally (over the outer side) of the shoulder – typically a catching type pain on raising the arm overhead or when throwing a ball. The supraspinatus tendon may be partially torn or swollen and rubs or catches under the acromion on lifting the arm up. The pain sometimes occurs as a result of overuse such as long distance swimming, but may also occur due to muscle imbalance in the shoulder.
For the most part a detailed description of how the pain started, what type of pain it is (sharp/ catching/ tingling, throbbing / dull ache) the location of the pain, things that ease the pain and what activities aggravate all help to narrow down what may be wrong. A careful examination is essential. X-ray and scans are not usually needed on the first instance unless there has been significant trauma and a fracture or major tendon tear is suspected. Most patients over the age of 50 will have some minor tear or arthritis on scans that might not necessarily be the cause of pain, like wrinkles – wear and tear changes are common as we age. Making the correct diagnosis ensures quicker recovery through the right exercises and therapy.