What Structures Cause Pain In The Shoulder?

There are several structures in the shoulder that can cause pain if they are injured. It is common to think that shoulder pain is always from a rotator cuff injury. This is not the case and determining what structure is the primary source of your pain is important to know how to treat the problem effectively. This article addresses some common ways that the various pain generators fo the shoulder are diagnosed from the perspective of an experienced Physical Therapist.

Three common pain generators of the shoulder are the rotator cuff muscles and tendons, the bursa and the shoulder capsule. The purpose of the rotator cuff muscles and tendons is to move our shoulder in a rotating fashion (hence their name) and to help up elevate our arms over our head. The purpose of the bursa or bursal sac is to protect the muscle from scraping on the edge of the bone. So the bursa sits between the muscle and the bone and acts like a cushion. Without it the rotator cuff muscles would repeatedly scrape on the edge of the bone and become easily irritated. The shoulder capsule offers added stability to the shoulder joint. Any one of these structures can become a pain generator if they are inflamed or injured. Often times they will be inflamed in conjunction with each other.

It can sometimes be tricky to diagnose the exact pain generator because the symptoms that are experienced by people with these pathologies are typically very similar to each other. More often than not these pathologies will cause symptoms of pain, weakness, and loss of motion. The pain is typically felt in the shoulder region and is often felt in the upper arm above the elbow. People with shoulder pain will commonly feel an increase in pain when they are trying to raise their arm overhead or out to the side. So if these pathologies are so similar in nature how can we tell them apart?

Well, in physical therapy there are some simple tests that can be performed that will help distinguish between the different pathologies described above. I will describe them here briefly.

1. Rotator cuff tendonitis: if one or more of the rotator cuff muscles is inflamed this is termed tendonitis. This is diagnosed by simple manual muscle testing where the physical therapist will resist specific motions of the shoulder that the rotator cuff is responsible for. If the patient experiences pain during a manual muscle test this is indicative of a tendonitis.

2. Bursitis: this can pose a challenge for the therapist to diagnose but if they are well trained they can more easily identify this as a problem. The tests start with manual muscle testing as described above. A painful manual muscle test should be followed by a Pull Test. This is a specific test that is specific to the bursa. If it is positive then it is likely that the person has a bursitis of the shoulder.

3. Adhesive capsulitis: this is also commonly known as frozen shoulder. The diagnosis of adhesive capsulitis is made with specific testing called passive motions. Limited range of motion of the shoulder is a common finding in any of the pathologies discussed in this article. Adhesive capsulitis presents with a very specific limitation in motion that will likely differ from the limited motion seen in tendonitis and bursitis.

If the symptoms of these pathologies can be so similar then why do we need to be so specific in the diagnosis? The reason is that although symptoms are similar the treatments for these conditions can vary slightly from each other. Treatment that I apply for a shoulder bursitis I may not apply for a shoulder tendonitis or adhesive capsulitis. When a specific diagnosis is made the Physical Therapist can design a specific treatment plan that will help alleviate shoulder pain. The more thorough the treatment plan the more likely the outcomes will be positive.