Shoulder Pain

Andrew D. Pearle

Russell F. Warren

KEY POINTS

The prevalence of shoulder pathologies varies with age, with instability and superior labral anterior posterior (SLAP) lesion common in the younger population, and impingement and rotator cuff disease more common in the older population.
A trial of conservative management including physical therapy, nonsteroidal anti-inflammatory drugs (NSAIDs), and subacromial injection are usually the initial management for shoulder impingement.
Rotator cuff tears are often associated with impingement syndrome and should be evaluated with careful examination as well as advanced imaging such as magnetic resonance imaging (MRI) or ultrasonography.
Adhesive capsulitis is characterized by stages that have distinct clinical manifestations and treatment strategies.
Acromioclavicular (AC) joint pain is diagnosed by physical examination, with attention to localized tenderness to palpation directly over the joint; radiographic findings support but do not establish the diagnosis.
Shoulder instability should be properly classified by its degree, frequency, etiology, and direction. Recurrent shoulder instability is more common in the younger, athletic population (>25 years old).

The diagnosis and treatment of problems of the shoulder region require an understanding of the anatomy and function of this joint.

The three joints of the shoulder are the acromioclavicular (AC), sternoclavicular, and glenohumeral articulations, and the gliding planes consist of the scapulothoracic surface and the subacromial space. Elevation of the arm is produced by the combined rotation of the glenohumeral joint and of the scapula on the chest wall.
The rotator cuff consists of four muscles, the supraspinatus, the infraspinatus, the teres minor, and the subscapularis. In addition to assisting in internal and external rotation, these muscles act to depress or “center” the humeral head during shoulder elevation. This centering action of the rotator cuff provides a fulcrum that allows the deltoid to elevate the arm rather than simply shrug the shoulder.
The glenohumeral joint has the most mobile articulation in the body and is the most commonly dislocated diarthrodial joint. Static shoulder restraints consist of the glenoid labrum, the articular anatomy, negative intra-articular pressure, joint fluid adhesion, and the capsuloligamentous structures. Dynamic shoulder stabilizers include the rotator cuff muscles, the biceps, and the periscapular muscles.

CLINICAL MANIFESTATIONS AND PHYSICAL EXAMINATION

Examination of the shoulder region includes observation, palpation, range of motion, strength testing, and special tests for specific pathologies. In addition, extrinsic sources of shoulder pain should always be considered, and evaluation of the cervical spine, entire upper extremity, and chest wall must be part of any shoulder examination.

I. OBSERVATION

The position of the shoulder relative to the contralateral side should be noted. Asymmetry in the form of an elevated or depressed position of the shoulder may be related to scoliosis, congenital spinal or shoulder deformities, or simply athletic activity.
Swelling about the shoulder may be secondary to inflammation of the joint, a bursa, or associated with rotator cuff tears.
Shoulder range of motion should be assessed; it is essential to visualize shoulder motion from behind the patient to note the scapulohumeral rhythm.
Specific muscle atrophy may indicate either rotator cuff tears or neurologic involvement.

II. PALPATION

The supraclavicular fossa should be carefully palpated for masses as well as for tenderness of the brachial plexus, which is seen in the thoracic outlet syndrome.
Local tender spots indicative of trigger points should be sought along the interscapular region and overlying musculature of the shoulder. If pressure is applied to these spots, radiation of pain into the upper arm may be observed.
Specific sites of tenderness that should be carefully palpated include the biceps tendon, the subdeltoid bursa, the rotator cuff, the AC joint, and the sternoclavicular joints.

III. MOTION

In examining the shoulder, one should observe the full range of active and passive motion, noting any discrepancy that may reflect a rotator cuff tear. Active elevation in the plane of the scapula may demonstrate altered scapulothoracic rhythm with a “shrug sign” if a rotator cuff tear is present.
Range of motion examination should include abduction in the plane of the scapula, and forward flexion. External rotation of the humerus is noted with the arm at the side as well as with 90 degrees of abduction. Internal rotation is recorded by placing the hand behind the back and noting which spinous process the thumb will reach. It is also tested at 90 degrees of abduction.

IV. STRENGTH TESTING

Strength testing includes evaluation of the shoulder flexion (anterior deltoid), abduction (middle deltoid), adduction (pectoralis major and latissimus dorsi), and extension(latissimus dorsi and posterior deltoid).
Rotator cuff strength must be evaluated with every shoulder examination. The supraspinatus muscle is evaluated by applying downward pressure to the arm when it is abducted to 90 degrees in the scapular plane and in maximal internal rotation. Weakness of external rotation with the arm at the side is present with large rotator cuff tears involving the infraspinatus or with C5-6 nerve root problems. The lift-off test for subscapularis tears is performed by placing the back of the hand over L5 and pushing away from the back. Loss of strength is associated with subscapularis tears.

V. SPECIAL TESTS

The impingement sign is positive in patients with rotator cuff inflammation or tears, and is noted by flexing the arm forward to the full overhead position. Pain is
present during the last 10 degrees of passive elevation. Passive abduction to the 90-degree position with internal rotation will similarly produce pain.
The impingement test is positive if a positive impingement sign is relieved with a subacromial lidocaine injection. A positive impingement test is indicative of impingement syndrome or a rotator cuff tear.
The cross-body adduction test consists of fully adducting the humerus across the chest. This test stresses the AC joint and will cause pain if degeneration of the AC joint is present.
The active compression test is performed with the arm straight and maximally pronated (thumb facing down) and the shoulder flexed to 90 degrees and adducted 15 degrees. Downward pressure is applied to the arm which places compression on the intra-articular portion of the long head of the biceps. Deep anterior pain and weakness with this test, which is relieved by performing the maneuver with the arm in supination is indicative of a superior labral anterior posterior (SLAP) lesion.
Instability of the glenohumeral joint is assessed by placing the patient in the supine position with maximal muscle relaxation. To evaluate anterior instability, the shoulder is placed in the abducted, externally rotated position and gentle pressure is applied in an anterior direction behind the humeral head. Instability is assessed by noting the degree of anterior humeral head translation. In addition, apprehension due to fear of dislocation with this maneuver is characteristic of anterior instability (apprehension test). Posterior instability is assessed with the shoulder adducted and internally rotated with pressure placed in the posterior direction; a click or a clear subluxation may be noted during this maneuver. In some patients, inferior instability is demonstrated by distracting the arms inferiorly to see if a sulcus forms (sulcus sign) distal to the acromion. This sign is frequently present in multidirectional instability.

VI. NEUROVASCULAR EXAMINATION

A complete neurologic examination should be performed. Weakness may be the result of intrinsic shoulder lesions, as in a cuff tear, or of nerve lesions of the brachial plexus or cervical roots.
The circulation of the arm and the hand must be carefully evaluated. Several tests are used for assessment of thoracic outlet syndrome.
- The Adson’s test consists of palpating the radial pulse while the patient’s head is turned to the involved side and a Valsalva maneuver is performed. A decrease in the pulse is suggestive, but not diagnostic, of thoracic outlet syndrome. A reduced radial pulse on testing should be compared with the pulse on the contralateral side.
- The modified Adson’s or Wright’s test is performed with the arm abducted and externally rotated, noting any decrease in the pulse.
- The Roo’s test is performed with the patient’s shoulders abducted and externally rotated; the patient is instructed to open and close the hands for 1 to 2 minutes in an attempt to reproduce the symptoms of thoracic outlet syndrome.