Shoulder injuries are a regular complaint in our practice, and account for the most common extremity disorder that we see. The shoulder itself is by far the most mobile joint in the body, with up to 180 degrees of motion in multiple planes. However, with the benefits of great motion comes the negative of also being a very unstable joint. Due to this instability, the surrounding soft tissues become damaged easily, and could result in pain, discomfort, and loss of motion.
Step 1: Scapular Dyskinesis
While shoulder injuries can occur from traumatic events, such as a fall or rapid hyperextension, it is much more likely that the problem gradually builds up over time before resulting in symptoms. In the majority of shoulder injury cases, the problem starts with bad mechanics of the shoulder blade, or scapula. This condition is called “scapular dyskinesis.” Scapular dyskinesis is caused mostly by posture-related muscle imbalances, particularly tightness in the pectorals and biceps combined with weakness in the lower trapezius and serratus anterior. Without turning this into an anatomy lesson, basically these muscle imbalances cause improper mobility of the shoulder blade during any motion of the upper arm, which may lead to pain and further shoulder complications.
Step 2: Impingement
If left uncorrected, scapular dyskinesis can lead to shoulder impingement. While many ailments of the shoulder can be lumped into the umbrella term as “impingement,” true shoulder impingement occurs when the top of the humerus jams into the upper-outermost part of the shoulder blade known as the acromion process. When these two come together, the shoulder bursa and/or rotator cuff tendons might get pinched, or impinged, between the two bones. Shoulder impingement classically presents with sharp pain while reaching overhead or behind the back, as these motions will push the humerus into the acromion. Pain at night is also common, and is often severe enough to prevent sleep.
Step 3: Rotator Cuff Disorder
Scapular dyskinesis leads to impingement, and impingement finally leads to rotator cuff disorders. Because the rotator cuff tendon is affected by the physical stress of the impingement, the most common pathology at this phase of progression is rotator cuff tendonitis. Tendonitis occurs
when inflammation pools up where the muscle inserts on bone. The impingement plus the tendonitis often leads to a damaged tendon tissue that is very difficult to heal. As this tissue becomes more and more compromised, the likelihood of a rotator cuff tear increases. Once again, a tear can happen from an acute event, but is much more likely to occur in the elderly population as the final stage of this continuum that has lasted for many years. Rotator cuff injuries commonly present with muscle weakness, shoulder pain (particularly at night), and limited range of motion.
The good news about shoulder problems is they can often be identified and
corrected before they develop into impingement or worse. Conservative treatment to mobilize the shoulder and scapula, combined with exercises to strengthen weak muscles and lengthen tight muscles are usually a great place to start. Ask how we can help!
Yours in Health, Dr. Alex