The shoulder is arguably the most mobile joint in the body so it’s no wonder why it’s often injured. The shoulder can be broken down into five joints; The glenohumeral joint, acromioclavicular joint, sternoclavicular joint, scapulothoracic junction, and suprahumeral junction. These joints work together to aid mobility and stability of the shoulder. When an imbalance occurs between these joints, impingement syndromes can occur.
There are several causes of impingement syndrome. The first being macrotrauma or microtrauma. This occurs during repeated motions that create stress on the tendons of the rotator cuff. Next is glenohumeral internal rotation deficiency (GIRD). Dr. Burkhart theorized that the loss of internal rotation, caused by tightness of the posterior capsule, is the primary lesion in the overhead shoulder. When this occurs, the superior portion of the rotator cuff is pressed against the coracoacromial arch, resulting in subacromial impingement. Third, muscular imbalances can occur. For example, the subscapularis can become tight and hypertonic. When this occurs the infraspinatus and teres minor become inhibited. Let me explain it a different way. If you just contract your bicep, your triceps muscles have to relax to allow the bicep contraction. Now just think if your bicep was always slightly contracted, your triceps muscles would be slightly relaxed and inhibited. Now back to the subscapularis, if this muscle is tight, it will cause the humeral head may shift anteriorly and impinge the anterior labrum. Finally, there can be weakness of the rotator cuff and scapular stabilizers. The role of the rotator cuff is to compress and depress the humeral head into the glenoid fossa. This means that decreased compression creates abnormal upward excursion of the humeral head which can lead to an impingement of the subacromial space. Weakness of the scapulothoracic muscles reduces scapular stabilization, allowing abnormal upward excursion of the humeral head which leads to impingement of the subacromial space. It’s important to evaluate the posture of the glenohumeral region to identify weak or inhibited muscles.
Now what? As you can see there can be a variety of conditions going on to cause shoulder discomfort. As a sports chiropractor I evaluate all causes of shoulder pain based on what our patient’s health history is, mechanism of injury, a previous injury to the shoulder, and palliative and provocative factors. From there I build a custom treatment and rehabilitation program that will address the underlying issues. Shoulder injuries, in my opinion, take longer to resolve because we just simply use our shoulders a lot every day. Simple movements like typing, driving, and writing require our shoulder muscles to work together to allow us to do these movements. Not to mention the other dozens of daily activities that we do that require our shoulders. If you have a shoulder injury, be patient and trust the process. You will get better.
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