Impingement Syndromes
Impingement is a word that gets used often in orthopedics indicating that a tissue has become compressed. Whether it be the shoulder, hip, ankle or spine, each region has its own form of impingement syndrome. Essentially, space has been exhausted and something like a tendon, nerve or other tissue has been sacrificed to create movement. The potential reality is that space affords the opportunity to move, without it, compensations may develop.
Impingement has been cited for many years as the cause for pain in a number of bodily regions. The shoulder is a very common place for this diagnosis. The theory is that one of the rotator cuff muscles, supraspinatus, gets caught between the acromion of the scapula and the head of the humerus during movement. This may in fact be the case, however the mechanism is complex. Traditional explanations describe weakness of the rotator cuff and compensatory activation of the upper trapezius as some of the causes for the issue. What if the trapezius is compensatory for the overactivity of its own middle and lower fibers, as well as other upper back musculature like rhomboids, lats, and even the rotator cuff? Maybe the inability to create an inward turn, like internal rotation of the humerus with respect to the scapula is part of the problem, and maybe that limitation is due to muscle activity behind the shoulder.
Typical rehabilitation programs focus on regaining some form of force production by the small rotator cuff muscles, as well as the other muscles of the upper back. The thinking being that improving the muscle mass in this area will allow it to handle greater forces, reduce pain and promote greater external rotation. The theory makes sense but could be improved upon. Most of our musculature is on our back side and it tends to have more leverage than muscles on our front side. If we use that leverage, joints begin to turn outward, limiting their inward turn and sacrificing range of motion in the process. Activities like reaching across your body, over head or behind your back become difficult because they all require some degree of internal rotation that is no longer accessible, and some tissue gets impinged in the process.
We may need to think deeper about the process of impingement. It may be a compensatory movement, however restoring motion of these regions via activities like box squats, concentration curls, or reverse sled drags could be potential solutions. Making space for the movement is key.
Austin Ulrich, Physical Therapist
