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Mets injury analysis of Steven Matz’s shoulder impingement

The lefty has a shoulder impingement, which sounds worse than it is.

Arizona Diamondbacks v New York Mets Photo by Rich Schultz/Getty Images

Steven Matz, who is scheduled to begin throwing again today, has been diagnosed with shoulder impingement. What does that mean and what is the recovery like?

What is shoulder impingement?

The shoulder complex consists of three bones: the clavicle (collarbone), humerus (arm bone) and scapula (shoulder blade). These bones work in conjunction to move the arm; as you move the humerus, the scapula moves accordingly while the clavicle is there for stability. Muscles attached to different areas of these bones allow movement of the arm. In between all of these bones and muscles is called a bursa, a sac filled with fluid to act as a cushion so the bones and muscles do not rub against each other.

Shoulder impingement occurs when the bursa and/or muscles in between these bones gets pinched causing pain and inflammation. Among the muscles in the area are the four muscles that compose the rotator cuff. Before Matz was diagnosed with shoulder impingement, he was sidelined for rotator cuff irritation; now a cause has been identified for the irritation.

Impingement could be a result of several mechanisms: poor posture, muscular imbalance between the upper trap/mid-back muscles or rotator cuff/deltoids, overuse of the shoulder leading to “wear and tear”, etc. While this may sound serious, it is rather an everyday diagnosis in physical therapy clinics and a common diagnosis for non-traumatic shoulder injuries.

What does rehabilitation look like?

A lot of the rehabilitation is strengthening the muscles around the scapula and being less reliant on the upper traps. The upper traps is a very big muscle and the muscles around the scapula are small in comparison; it is very easy for people to have their upper trap dominate the smaller muscles causing them to be weak and underutilized. To strengthen these smaller muscles requires fixing one’s posture. Exercises will obviously strengthen the smaller weak muscles, however the patient will have to be conscious of his posture to cause a meaningful change.

Other exercises will strengthen the rotator cuff as the injury has resulted in weakness, while physical therapists will use manual techniques in attempt to create more space in between the bones to facilitate more pain-free movement. In the end, the goal is the make sure four joints that make up the shoulder complex have full range of motion and move well together without inciting any pain or inflammation.

It is tough to say when Matz will be back but this is not an injury that requires extensive rehab or prolonged absence from the rotation. Like everyone, he just has to make sure that he works on his posture and strengthens the smaller mid-back muscles that surround the scapula.