There are many layers of tissue in all joints of the body: skin, fat, muscle, nerve, bone, ligaments, tendons, blood vessels, fascia and other connective tissue. The shoulder joint, as you can see above, is a particularly complex area. This picture is not comprehensive, and only a sample of the anatomical structures that compose the shoulder. There are even more that communicate between both the shoulder and cervical spine.
Historically, in cases of shoulder pain a singular structure has been identified as the source of the patient's ailment: rotator cuff tendonitis/tear, bicep tendonitis, bursitis, labral tear, etc...
However, focusing on singular structures is a bit dubious, due to the poor specificity of special tests, and the level of false-positive results from both physical examination and imaging (MRI, X-Ray). Despite showing structural abnormality, symptoms often reduce and resolve with appropriately prescribed movements. It is only when conservative measures fail to resolve symptoms, that structural or anatomical intervention should be considered.
Musculoskeletal diagnoses are now more often generalized to the region of the pain: shoulder, elbow, wrist, neck, etc. This allows for an unbiased, independent evaluation and examination to be performed by your physical therapist.
In cases of shoulder pain, one of the most important (and often missed) hypotheses to rule in or out is the possibility of cervical radicular pain. Radiculopathy can sound scary, but the severity has considerable variability and in many cases it is treatable with conservative measures. Take a look at this picture:
These are some common referral patterns of a neck dysfunction. As you can see, the shoulder is involved in many of them. And as you can imagine, or may have even experienced, treating a referred pain as if it a shoulder problem will not be very successful.
Here's some evidence for the problem from the literature:
In a sample of 332 industrial workers, a team of researchers investigated the prevalence of cervical contribution to shoulder pain. This is what they found:
220 individuals reported pain in the arm.
64 reported primarily shoulder pain, 44% of which also presented with cervical joint dysfunction.
43 reported primarily elbow pain, 65% of which also presented with cervical dysfunction
74 reported primarily hand symptoms, 55% of which also presented with cervical dysfunction
Some important takeaways from this study: The sample size is relatively small, and from a specialized group of workers. So the specific numbers aren't necessarily directly generalizable to the public. However, this investigation does highlight the potential for a relatively high incidence of cervical dysfunction with upper extremity pain.
When correctly classified, cervical dysfunction referring to the upper extremity can have an excellent prognosis.
So if you have been treated for shoulder pain (unsuccessfully), with interventions aimed solely at the shoulder, it is possible that you would benefit from a second opinion which evaluates the relationship of your symptoms to your cervical spine.
Thanks for reading,
Dr. Piotr