The shoulder is the one of the most mobile joints in the human body. It owes its mobility to the shallow socket of the glenohumeral joint (where the head of the humerus attaches to the glenoid of the scapula), the mobility of the scapula itself and the surrounding musculature. Due to this large range of motion and the complexity of the joint, the shoulder can have a high rate of injury and dysfunction.
One of the most common causes of shoulder pain is subacromial impingement. This occurs when there is mechanical compression of subacromial structures between the coraco-acromial arch and the humerus during active movement of the arm above shoulder height. Symptoms include pain with overhead activities, pain during activities of daily living e.g. hanging out washing, and pain at night when lying on the affected side. Common structures involved include; tendons of the rotator cuff (specifically the supraspinatus muscle), long head of biceps tendon, and the subacromial bursa.
Direct trauma from a fall, sporting injury or motor vehicle accident can result in altered shoulder biomechanics and lead to subacromial impingement. More common causes include; poor postures and ergonomic habits at work e.g. long hours sitting at a computer or desk with rounded shoulders, repetitive stress and movement patterns e.g. production line work, labouring or sports such as tennis with repeated strokes, rotator cuff tears or weakness which result in poor positioning of the head of humerus in the glenoid, abnormal muscle activation of surrounding structures and other anatomical variations.
Diagnosis of subacromial impingement can be given by a Physiotherapist based on patients subjective reporting of pain, clinical examination and testing, x-ray and/or MRI results. A variety of treatment options are available such as pain medications, rest and ice for pain management, however until the cause is determined and corrected, the problem will continue to reoccur.
Physiotherapy management should focus on correcting poor postures, movement patterns and work ergonomics, as well as changes to aggravating movements e.g. stroke correction in tennis or golf. Joint manipulation, soft tissue massage and trigger point release of tight or overactive structures pulling the shoulder into undesired positions. Electrophysical treatment modalities such as therapeutic ultrasound and TENS can be used for pain management and to aid in healing. Acupuncture or dry needling may also be an added treatment adjunct for overactive muscles. Finally specific and individualised strengthening and stretching program should be prescribed with the goal to help centre the humeral head in the joint and correct scapulohumeral rhythm.
After pain has decreased, full shoulder range of motion has returned and the patient is able to return to normal activities of daily living or return to sport, referral to an Exercise Physiologist should be given for a continued specific strength and conditioning program to maintain optimal shoulder positioning and biomechanics and ensure the problem does not reoccur.