Shoulder Impingement Syndrome
Shoulder impingement syndrome involves compression of non-neural soft tissues between the head of the humerus and the underside of the coracoacromial arch. Impingement can lead to tissue degeneration and is subsequently associated with a number of other shoulder disorders, such as tendinosis, rotator cuff tears, calcific tendinitis, bone spurs, and subacromial bursitis.
Characteristics of soft-tissue impingements occur in the shoulder as tissues are compressed underneath the coracoacromial arch. Impingement can result purely from the structure of the coracoacromial arch, but can also occur from repetitive motions, especially from flexion and internal rotation of the humerus. In some cases bone spurs or osteophytes develop on the underside of the acromion process and serve to further compress the room for the nerve and impinge tissues in the area. Myofascial trigger points or hypertonic muscles in the shoulder region can also cause dysfunctional biomechanical issues and lead to impingement problems in the shoulder.
There are no clear observable signs that someone may have shoulder impingement syndrome. There however, may be inflammation, visible indicators may be absent. When conducting movement active range of motion testing clear signs to smoothness in motion or the lack of smoothness in movement can take place during an evaluation. There also may be clear visible apprehension when attempting to perform abduction or flexion of the shoulder.
Compensating for movement can cause irregular patterns of motion which are evident as the client attempts to avoid actions that clearly provide pain in movement. Postural distortions such as upper thoracic kyphosis and medially rotated glenohumeral joint should be noted as they change glenohumeral actions which lead to impingement.
Patients that usually would see this type of syndrome come from two different sides of the spectrum in age the younger crowd, and an older crowd. The causes in the two age groups are usually different. The younger crowds usually see this syndrome from repetitive motion while doing abduction of the shoulder for long periods of time such as people working in factory or athletics. The older crowd would see this syndrome from a completely different set of circumstances. The older crowd may develop impingement with less activity due to hooked acromion, bone spurs, osteophytes, or overall tissue degeneration.
If is difficult to produce the pain of the impingement because of its location under the acromion process. However, if the impingement affects the distal supraspinatus tendon or the subacromial bursa, tenderness is common inferior to the acromion process on the lateral shoulder. Excess edema or other palpable signs of inflammation such as heat are normally not identifiable because of the depth of the tissues involved. Palpating the anterior shoulder region, particularly if performed with the shoulder in flexion may cause pain in the shoulder.
Diagnosing the condition can be done through several testing methods suing Active Range of motion, Passive Range of motion and muscle resistive testing. Any of the testing will cause pain when the nerve is further compressed by the action of movement in the shoulder. The special tests that can be performed are the Hawkins-Kennedy Impingement Test, Empty Can Test, and Neer’s Impingement Test.
The Hawkins-Kennedy Impingement Test is performed while the patient is facing the therapist. The therapist brings the patient’s shoulder and elbow into 90 degrees of flexion. From this point the humerus is medially rotated by the therapist until the end range of motion is met. If this movement reproduces the client’s primary discomfort, there is a good chance that tissue is impinged under the coracoacromial arch. This does not completely rule out the exact tissues affected because numerous tissues can be compressed in the final position of the arm.
The second test that can be conducted is the Empty Can Test, which is normally performed bilaterally, even when one shoulder is symptomatic. The non-affected side is used for compression. If pain is reproduced at any of the points during the test, continuing the test is unnecessary because of the pain that will be produced by this motion. The client faces the therapist and brings the arms both at the same time to 45 degrees of horizontal adduction. While the position is held patient is asked about discomfort or pain that may be involved in holding the position. From this position the patient is asked to medially rotate the arms as if to pour the liquid out of the cans. At the end of the motion the therapist should ask about pain levels or discomfort. While the patient holds the final position while the therapist pushes down both arms with moderate effort. If pain is reproduced in this position the test is positive.
The third test that can be performed is the Neer Impingement Test, while the patient is facing the therapist. The therapist brings the arm into full forward flexion. The therapist needs to watch for signs of apprehension and ask about the pain levels or discomfort during the movement. Pain that is reproduced that is the same in the primary complaint indicates a positive test.
Suggested treatment involves soft tissue impingement in the coracoacromial arch to relieve the compression of the tissues is to reduce compression in the area. One can look for other trigger points that may be causing muscles to be hypertonic or have Myofascial trigger points. Massage and stretching should be used to address the situation. Treating the surrounding muscles may also be helpful in addressing the situation or complaint.
