By Dan Summerkamp, D.O.
The ins and outs of non-traumatic rotator cuff injuries
The most common cause of shoulder pain can be traced back to the rotator cuff in some way shape or form. In the previous installment, John did an excellent job of explaining what the rotator cuff is and why it is important so I will just give you the highlights. Most frequently when someone says, “I injured my rotator cuff” they are talking about the supraspinatus muscle that sits on the top of the shoulder joint. The cuff is completed by the infraspinatus and teres major supporting the back side of the shoulder, and the subscapularis in the front. Together their job is to provide stability for the shoulder joint while simultaneously helping to produce the large range of motion that we take advantage of performing a variety of activities.
As a clinician who sees a variety of muscle and joint related injuries, shoulder problems can be some of the more challenging. I say this because quite often there is not a single, clear cut event that caused the painful symptoms to start. No falls, just a “Doc, I woke up with it the other day but didn’t do anything to it.” When I hear that I know instantly that this injury has been a long time coming. Most rotator cuff tendinopathies are the result of repeated microtraumas over a lifetime. These microtraumas cause repeated inflammation in the tendons of the rotator cuff, ultimately resulting in the formation of pain sensitive scar tissue.
A hopefully short point of clarification: Many people have heard the term “tendinitis” (inflammation). However, the term tendinosis(chronic degeneration) would be more accurate due to the histological (cellular) changes that occur with repeated injuries to tendons. The manner in which these two distinct pathologies are treated is completely different. I used the term tendinopathy because it covers both the “itis” and “osis” for the sake of simplicity.
As with all recurring and chronic injuries, rotator cuff tendinopathy requires a thorough examination to define why the repeated injuries happened in the first place. As John had mentioned in his article, the shoulder is an inherently unstable joint. When this stability is lost we then get injured. The base of support for the shoulder joint is the scapula a.k.a. the shoulder blade. Before we move our arm, the brain should automatically contract the muscles connecting the scapula to the rib cage and spine, thereby creating stability while still allowing use to move our arm. There is an intricate balance between opposing muscles that can easily be disrupted. Surprise, surprise, when the balance is lost the mechanics change and the rotator cuff gets injured.
Notice in the picture below how the gentleman’s right shoulder shrugs up towards his ear when be raised his arms up to his side. This is a classic example of abnormal motion in the shoulder complex. Essentially every time he brings his arm up his supraspinatus tendon is being crushed between the tip of his shoulder blade and his upper arm. It is pretty obvious how this will result in injury.
Taking the step of assessing how the shoulder and scapula move in relation to one another is of the utmost importance for those undergoing surgery because if the mechanism causing the injury is not addressed, the cuff will be injuries all over again after the surgery. In the same breath, having a chiropractor of physical therapist that understands this relationship is vital if you are to avoid surgery or are recovering from surgery.
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