The shoulder is a very common site of musculoskeletal pain. We hear terms like "bursitis" and "frozen shoulder" but what do they mean? And what exactly does cause shoulder pain?
This blog post will address some of the more common causes of shoulder pain.
Subacromial Pain Syndrome
The most common cause of shoulder pain, here the pain arises from the subacromial bursa being compressed and/or an injury to the rotator cuff muscles. In order to allow the shoulder its large range of movement in three planes while still remaining stable, there needs to be a fairly complicated coordination of movement involving a number of different muscles and joints within the shoulder complex. Imperfections in this coordination can potentially lead to the subacromial bursa and/or rotator cuff muscles being under too much load and then becoming inflamed and painful.
For more info on this very common condition you can read our earlier blog post on the topic here
Frozen shoulder (or "adhesive capsulitis") is a process where there is a chronic inflammatory process in the shoulder joint capsule due to an auto-immune response. That is to say, the immune system decides to attack the shoulder joint capsule. This happens most commonly following shoulder surgery, but can also occur after a shoulder injury, after being unwell, and sometimes it can even occur seemingly out of the blue.
The chronic inflammation in the shoulder joint capsule causes the shoulder to be painful and also to lose it's range of movement. The good news is that the process is self-limiting, meaning it does eventually stop itself, but usually not for six months or more. The other good news is that gentle manual therapy and range of movement exercises can help maintain a fairly functional range of movement while the process is occuring.
The shoulder is a common site of referred pain from either the lower segments of the neck, or the upper segments of the upper back.
Joints between the vertebrae (either facet joints or intervertebral discs) can be injured and become sore and inflamed, similar to spraining an ankle or any other joint. If a joint between C4 (in your neck) and T4 (in your upper back) is injured then you may get a somatic pain referral to the shoulder or upper arm. (Somatic pain referral is simply the brain misinterpreting pain from one site as coming from another site, and there are fairly clear patterns to this).
In the upper back there are also the costovertebral joints, where the ribs attach to the spine. These joints can also be sprained, and the top four costovertebral joints can potentially refer to the shoulder and upper arm.
Pain may or may not also be felt in the neck or upper back.
Nerves which supply the arm may also be irritated or compressed as they exit between the vertebra in the neck, or as they pas through the thoracic outlet (between the neck and the shoulder.). As a result you can also get neural pain referral to the shoulder and upper arm. Neural pain referral is often constant and of higher severity. It may also be accompanied by neural symptoms such as pins & needles, numbness or muscle weakness. Generally the nerves are getting irritated or compressed by inflammation, muscle tightness or other things treatable through physiotherapy. On some occasions, however, this condition may need to be treated with injections and/or surgery etc.
These are the more common causes of shoulder pain, but there are other potential causes as well. If you're suffering shoulder pain and want help finding what's causing it and getting it treated, come see our physiotherapist in Aubin Grove today!