What is Causing Your Shoulder Pain?
Our shoulders are one of the most complex joints in our entire bodies. They are designed to perform an incredible variety of movements and functions; even though those functions are more suited to the outdoor life our distant ancestors lived more so than the relatively sedentary lives we all lead today.
As a result of this imbalance, shoulder pain is one of the most common complaints we hear about from our patients. We have discussed the specific anatomy of the shoulder in previous articles and why it is predisposed to a variety of pain and injury, but today we are going to take a closer look at one of the most common diagnosis in one of the most commonly painful joints – shoulder impingement.
As frequently happens with many musculoskeletal diagnoses that are all too common, despite the real and actual prevalence of shoulder impingement, it gets over diagnosed and is used to describe almost anyone with shoulder pain that doesn’t have an obvious fracture or tear of the rotator cuff or labrum.
So what is shoulder impingement? Generally, it is defined as a pinching or impinging of the rotator cuff tendons/muscles (which are some of the prime movers of the shoulder). The tendons can be caught between the head of the humerus (the upper arm bone) and the acromium process of the scapula (part of the shoulder blade). Unfortunately, even though this is where most diagnosis of shoulder pain stops, this is not specific enough as there are two different ways that impingement can be happening of the same muscles between the same structures, but that require notably different treatments.
The primary distinction between those two types of impingement is whether those muscles are being impinged outside of the capsule of the shoulder or inside the capsule. Internal impingement is the more specific diagnosis when the tendons are being compressed or impinged intra-articularly. External impingement, or sub-acromial impingement, is when the tendons are being compressed extra-articularly.
This significance of this seemingly minor distinction is that successful treatment requires different approaches. So how can you tell if you shoulder pain is being caused by internal versus external impingement? First, consider the location of your pain; Internal impingement pain is usually felt just behind the shoulder whereas external impingement is usually felt on top of the shoulder or on the outside of the arm.
Second, recognize that internal impingement occurs in younger athletes that perform a lot of overhead activity like throwing or swimming, whereas external impingement generally occurs later in life and may be more associated with general overuse or general deconditioning.
Your physical therapist will be able to further diagnose the difference with a variety of special tests, but knowing the difference and being specific about your symptoms will help ensure that you are properly diagnosed and treated.
