STERNOCLAVICULAR JOINT

The sternoclavicular (SC) joint is a spheroidal joint between the medial end of the clavicle and both the manubrium and the first costal cartilage. An intraarticular fibrocartilaginous disk stabilizes the joint and prevents medial displacement of the clavicle. The joint capsule is reinforced by the anterior and posterior SC ligaments.

ACROMIOCLAVICULAR JOINT

The acromioclavicular (AC) joint is a spheroidal joint between the lateral end of the clavicle and the acromion process of the scapula (Figure 2-1). A small, intraarticular fibro cartilaginous disk divides the joint into two compartments. A subcutaneous, noncommunicating bursa may be present over the joint. The stability of the AC joint depends on the capsule and the superior and inferior AC ligaments. The coracoclavicular ligament (conoid and trapezoid parts) extends between the distal clavicle and the coracoid process of the scapula (Figure 2-2). It suspends the scapula, stabilizes both the clavicle and the scapula, and maintains a close relation between the two bones during shoulder movements, thus limiting scapular rotation around the AC joint. The AC and SC joints augment the range of shoulder movements, particularly abduction and rotation. The joints also allow slight axial rotation of the clavicle, as well as elevation/depression and forward/backward thrusting of the shoulder.

FIGURE 2-1 THE SHOULDER.

FIGURE 2-2 THE SHOULDER (SYNOVIAL MEMBRANE AND OUTPOUCHINGS).

GLENOHUMERAL JOINT

The glenohumeral (GH) joint, the main articulation of the shoulder complex, is a multiaxial, ball-and-socket synovial articulation between the glenoid fossa of the scapula and the humeral head (Figure 2-1). The lax articular capsule and the small area of contact between the shallow glenoid fossa and the spheroidal humeral head permit a wide range of motion. The stability of the joint depends on a number of static and dynamic stabilizers. Static stabilizers include negative intraarticular pressure; GH bone geometry; the capsule; the glenoid labrum; the superior, middle, and inferior GH ligaments; and the coracohumeral ligament. The capsule, which fuses in part with the tendons of the rotator cuff, has two apertures: one for the long biceps tendon (origin from the supraglenoid tubercle) and one for the subscapularis bursa. The labrum, a ring of fibrocartilage that surrounds and deepens the glenoid cavity, contributes significantly to GH joint stability. Through a bumper effect, it functions as a “chock block” to prevent translational forces.

The inferior GH ligament complex is the primary ligamentous stabilizer of the abducted GH joint and serves to prevent anteroinferior shoulder dislocation. The middle GH ligament is tensioned at 45° of abduction, and the superior GH ligament is tight in adduction.

Dynamic stabilizers play an important role in the stability of the shoulder. They include two musculotendinous layers: 1) an inner stratum, made of the rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) and the long biceps tendon (origin from supraglenoid tubercle from glenoid fossa), and 2) an outer stratum, composed of the deltoid, teres major, pectoralis major, latissimus dorsi, and trapezius muscles.

The muscles of the inner stratum stabilize and retain the humeral head in the glenoid cavity during shoulder movements (cavity-compression mechanism), while simultaneously providing abduction (supraspinatus—origin from the supraspinatus fossa of scapula and insertion into the superior part of the greater tuberosity), external rotation (infraspinatus and teres minor—origin from the infraspinatus fossa and axillary border of the scapula, respectively, and insertion into the posterior aspect of the greater tuberosity), and internal rotation (subscapularis—origin from the subscapularis fossa and insertion into the lesser tuberosity). At the initiation of shoulder abduction, both the rotator cuff and the long biceps tendon depress and stabilize the humeral head against the glenoid cavity to counteract the upward pull of the more powerful deltoid muscle. The mechanism whereby these two groups of muscles combine to produce abduction, the one (deltoid muscle) elevating and the other (rotator cuff and biceps tendons) stabilizing the humeral head, is termed force-coupling. The muscles of the outer stratum are the prime movers of the shoulder. These provide abduction, flexion, extension, adduction, and some degree of rotation.

The coracoacromial arch—made up of the coracoid process, coracoacromial ligament, and acromion—acts as a protective, secondary socket for the humeral head, under which the rotator cuff tendons and long biceps tendon glide, with the subacromial bursa lying in between. The arch prevents upward displacement of the humeral head and protects the head and rotator cuff from direct trauma. The undersurface of the acromion is commonly flat (type 1); less frequently, it is downwardly curved (type 2) or hooked (type 3), but these conditions are more commonly associated with subacromial impingement.

The synovium of the shoulder lines the inner surface of the capsule. It has two extracapsular outpouchings, the tenosynovial sheath of the long biceps tendon and the bursa beneath the subscapularis tendon (Figure 2-2). A communicating infraspinatus bursa is sometimes present. The subcoracoid bursa lies between the shoulder capsule and the coracoid process, but it rarely communicates with the joint.

SCAPULOTHORACIC MOVEMENTS

The so-called scapulothoracic articulation is not a true joint but functions as an integral part of the shoulder complex. The scapula, which is connected to the posterior aspect of the chest wall by the axioappendicular muscles, provides the origin for the rotator cuff muscles and deltoid, and the trapezius inserts into its superior aspect. Scapulothoracic movements that include rotation, elevation, depression, protrusion, retraction, and circumduction are important for the normal functioning of the shoulder. The scapulothoracic bursa is located between the serratus anterior and the chest wall, just medial to the inferior angle of the scapula.

NERVE SUPPLY TO THE SHOULDER JOINT

The shoulder joint derives its nerve supply from three branches of the brachial plexus: suprascapular, axillary, and lateral pectoral nerves (C5/C6). The axillary nerve and the posterior circumflex humeral artery pass through the quadrilateral or quadrangular space, which lies inferoposterior to the GH joint, bounded by the teres minor superiorly, the teres major inferiorly, the long head of triceps medially, and the shaft of the humerus laterally (Figure 2-3).

FIGURE 2-3 ARRANGEMENT OF THE BRACHIAL PLEXUS AND ITS TRUNKS, CORDS, AND TERMINAL BRANCHES.

(From Rockwood CA, Matsen FA, Wirth MA, et al., eds.:The Shoulder, 4th ed. Philadelphia: Saunders, 2009.)

SHOULDER PAIN AND HISTORY TAKING

Shoulder pain is a common symptom of diverse causes (Table 2-1). The pain may originate in the GH or AC joint or in periarticular structures, or it may be referred from the cervical spine, brachial plexus, thoracic outlet, or infradiaphragmatic structures. Important points in the history include age, hand dominance, occupational and sport activities involving heavy lifting or overhead repetitive movements, history of trauma, onset, location, character, duration, radiation of the shoulder pain, aggravating and relieving factors, presence of night pain, and the effect on shoulder function. Associated symptoms—shoulder stiffness, restriction of movement, grinding, clicking, instability, or weakness—may also provide useful diagnostic clues.

TABLE 2-1 DIFFERENTIAL DIAGNOSIS OF SHOULDER PAIN

AC, acromioclavicular; GH, glenohumeral; OA, osteoarthritis; PsA, psoriatic arthritis; RA, rheumatoid arthritis

It is also important to determine whether the shoulder pain is isolated or associated with other stiff, painful, or swollen joints. Shoulder pain may be a feature of a more systemic arthritis. Other joint history, and a history of systemic features, may need to be taken into consideration.

ROTATOR CUFF PATHOLOGY

The spectrum of rotator cuff pathology ranges from mild rotator cuff tendinopathy to partial and complete rotator cuff tears. If the tear increases in size, a massive rotator cuff tear (< 5 cm) may develop. This can lead to the proximal migration of the humeral head and secondary GH osteoarthritis (cuff tear arthropathy).

Causative factors include repetitive low-grade trauma or unaccustomed activities, excessive overhead use in sport or work, lack of conditioning, aging, and compromise of the rotator cuff space by osteophytes on the undersurface of the AC joint, type 2 or 3 acromion, or an os acromiale (unfused acromial epiphysis). Abnormal tensile stresses that exceed the elastic limits of tendons can lead to cumulative microfailure of the molecular links between tendon fibrils, called fibrillar creep. With aging, tendons become less flexible and less elastic, making them more susceptible to injury and tears. A short-ended musculotendinous unit, from lack of regular stretching exercises, is also prone to injury.

In young persons, rotator cuff tendinopathy is often caused by a sport-related injury; for example, from use of the arm in an overhead position in baseball, racquetball, tennis, or swimming. In older individuals, an antecedent history of repetitive movements above the shoulder level or of strenuous or unaccustomed arm activity is common. Symptoms include aching pain in the shoulder, lateral aspect of the upper arm, and deltoid insertion; pain with movement, particularly abduction and internal rotation; night pain when rolling onto the affected side; restriction of shoulder movements; and sometimes weakness caused by a rotator cuff tear. The patient typically experiences shoulder pain on active abduction, especially between 60° and 120°, and difficulty with overhead work, lifting, or reaching behind the back when dressing. Clinical findings include a painful arc between 60° to 120° of abduction, limitation of active movement by pain, and tenderness localized to the rotator cuff and greater tuberosity. The supraspinatus test, Neer impingement test, Neer impingement sign, and Hawkins impingement sign (see Special Tests of Shoulder, p. 13) are often positive.

Rotator cuff tears can be partial or complete, acute or chronic, small or massive. In young adults, acute tears often result from direct trauma or a sport-related injury. In older patients, minor trauma, superimposed on cuff tendon that is already frayed from chronic impingement and age-related attritional changes, can lead to tears.

Clinical features include shoulder pain on abduction, night pain, varying degrees of weakness of abduction and external rotation, local tenderness, wasting of the supraspinatus and/or infraspinatus muscles, and loss of range of motion with difficulty elevating the arm to greater than 90° without shrugging the shoulder (positive shrug sign). The supraspinatus test, Neer impingement sign, and Hawkins impingement sign are usually positive. Rupture of the long biceps tendon may also be present. In complete tears, the drop-arm sign is positive. The diagnosis of rotator cuff tears can be confirmed by ultrasonography, magnetic resonance imaging (MRI), or arthroscopy.

BICIPITAL TENDINITIS

Bicipital tendinitis often results from chronic subacromial impingement occurring in association with rotator cuff tendinitis and rotator cuff tears. Primary isolated bicipital tendinitis is rare and develops as an overuse injury resulting from repetitive stresses applied to the tendon in certain sports, such as weight lifting and ball throwing. Anterior shoulder pain that is increased by overhead activities, shoulder extension, and elbow flexion is the main symptom. There is localized tenderness over the tendon in the bicipital groove, the Yergeson sign (see Tests for Biceps Tendon, p. 16) is present, and the speed test is often positive. Passive extension of the shoulder or resisted flexion of the elbow may also reproduce the pain. Signs of chronic impingement and GH instability are often present. Rupture of the long biceps tendon is associated with a positive Popeye sign.

Subluxation of the bicipital tendon is caused by traumatic rupture of the intertubercular (transverse humeral) ligament. It is associated with anterior shoulder pain, a clicking sensation of the shoulder as it “goes out and pops back in,” tenderness in the bicipital groove, and a positive transverse humeral ligament test.

ADHESIVE CAPSULITIS

Adhesive capsulitis, also known as frozen shoulder, is characterized by progressive global restriction of shoulder movements and is associated with pain and functional disability. A period of immobility of the shoulder is the most common predisposing factor. The capsulitis may be secondary to shoulder trauma, rotator cuff tendinitis or tears, bicipital tendinitis, or GH arthritis, or it may coexist with diabetes mellitus, hypothyroidism, or cerebrovascular events. An initial synovitis phase is followed by fibrous thickening and contracture of the capsular folds, axillary recess, rotator cuff interval, and coracohumeral ligament. The shortening of the coracohumeral ligament and rotator cuff interval acts as a tight checkrein, limiting external rotation. Capsular adhesions are rare.

The clinical course can be divided into four overlapping stages. In stage I, there is painful limitation of active and passive shoulder movements with diffuse synovitis on both arthroscopy and biopsy. Stage II is a painful “freezing” phase; shoulder pain, tenderness, and progressive, painful, global restriction of movements are present, as well as characteristic limitation of external rotation in the absence of GH arthritis. Synovial inflammation and a tight, thickened capsule are observed on both arthroscopy and biopsy. In stage III, an adhesive or “frozen” phase, there is minimal pain; movements are markedly restricted, and the patient is unable to elevate the arm to 90° without shrugging the shoulder (positive shrug sign). Disuse atrophy of the deltoid and scapular muscles is common. A thickened, contracted capsule and fibrotic synovitis are observed on both arthroscopy and biopsy. In stage IV, a resolution or “thawing” phase, pain is minimal with an increasing range of motion.

Criteria for diagnosis of adhesive capsulitis include an insidious onset, true shoulder pain lasting longer than 3 months, night pain, painful restriction of all active and passive movements with external rotation reduced to less than 50% of normal, and a normal radiologic appearance. Although 90% of patients recover some use of the extremity within 12 to 18 months, about 40% develop more prolonged pain, restriction of movement, and functional disability.

GLENOHUMERAL INSTABILITY

TRAUMATIC LESIONS OF THE ACROMIOCLAVICULAR JOINT

Trauma to the AC joint can lead to disruption of the capsule, ligaments, and fibrocartilaginous disk. Local pain, tenderness, swelling, and a painful arc from 90° of abduction upward are the main findings. Pain at the AC joint can be reproduced by passive adduction of the extended shoulder behind the back (adduction stress test) and by abducting the shoulder 90° and then adducting it across the chest at shoulder height, compressing the AC joint (cross-arm AC-loading adduction test).

ARTHRITIS OF THE SHOULDER

Both inflammatory arthritis, such as rheumatoid arthritis, and degenerative arthritis, such as osteoarthritis, can affect the shoulder joints. Inflammatory arthritis may involve the AC, GH, or SC joint, and the patient may experience swelling and tenderness of the affected joints. The shoulder is painful with range of motion in all directions, and range may be limited. Other synovial joints in the body are often affected, and treatment is generally directed toward the systemic condition.

Primary osteoarthritis is common in the AC joint and less common in the GH joint. In some cases it may occur at the GH joint secondary to an inflammatory process. In osteoarthritis the shoulder is generally painful with activity and may get progressively worse over time. It is painful throughout the range of motion, which is often limited. Crepitus is classically felt over the affected joint.

NEUROLOGIC LESIONS ABOUT THE SHOULDER

Thoracic outlet syndrome is often caused by compression of the lower brachial plexus and subclavian artery between the scalene muscles or by a cervical rib. It is associated with shoulder pain, which often radiates distally along the ulnar border of the forearm and hand. Pallor, coldness, and numbness, commonly of the ring and little fingers, may occur. The Adson maneuver is often positive: the ipsilateral radial pulse disappears when the patient abducts, extends, and externally rotates the shoulder while taking a deep breath with the head rotated maximally toward the affected side. Neurologic findings are subtle and affect both interosseous and hypothenar muscles, as well as cutaneous sensation of the little and ring fingers and the ulnar aspect of the forearm. Compression of the subclavian artery can be demonstrated by MRI-angiography.

Acute brachial plexus neuritis (acute brachial plexitis or brachial neuralgic amyotrophy) is an uncommon disorder characterized by a rapid onset of burning pain in the shoulder and upper arm, followed a few days later by profound upper-arm weakness affecting multiple muscles supplied by the upper brachial plexus: supraspinatus, infraspinatus, deltoid, and sometimes biceps. Diagnostic studies include electromyography (EMG) and MRI. The course of the neuritis is usually one of gradual recovery in 3 to 4 months.

Quadrilateral space syndrome is a rare disorder that results from compression of the axillary nerve and posterior circumflex humeral artery in the quadrilateral space. It is caused by athletic activities, GH dislocation, or shoulder surgery. Nondermatomal pain and paresthesia of the shoulder and upper posterior arm, exacerbated by abduction and external rotation, are the main symptoms. Tenderness over the quadrilateral space, aggravation of symptoms by external rotation, variable atrophy and weakness of the deltoid and teres minor muscles, and sometimes sensory loss over the anterolateral aspect of the shoulder and upper arm are the principal findings. The diagnosis can be confirmed by EMG, MRI, or MRI-angiography.

Suprascapular nerve entrapment syndrome is characterized by deep aching pain in the upper posterior aspect of the scapula, made worse by shoulder adduction, and by weakness of abduction and external rotation. It is caused by compression of the suprascapular nerve in the suprascapular notch, beneath the suprascapular or transverse scapular ligament, or by a ganglion or lipoma. It can also result from repetitive trauma due to excessive overhead movements. Local tenderness over the suprascapular notch and variable weakness and wasting of the supraspinatus and infraspinatus muscles are the main findings.

Cervical radiculopathy, caused by a cervical disk lesion, is associated with pain in the shoulder, radicular sensory symptoms, motor weakness, and reflex changes. Radicular pain and/or paresthesia may be reproduced by one of two tests. The Spurling test involves a combination of cervical spine extension and tilt toward the affected extremity with pressure applied downward on the patient’s head. In the upper extremity root extension test, the patient’s arm is extended, abducted, and externally rotated with the elbow and wrist extended, and the head is tilted to the opposite side. Diagnostic studies include cervical spine radiography, MRI, and nerve conduction studies.

INSPECTION

With the patient sitting or standing and disrobed to the waist, both shoulders are inspected for symmetry, abrasions, scars, erythema, swelling, deformity, or muscle wasting. Subluxation of the AC joint is associated with a step deformity, with the acromion lying inferior to the clavicle. Swelling and prominence of the SC or AC joint may indicate arthritis or subluxation. Inferior subluxation of the GH joint is characterized by a positive sulcus sign: presence of a hollow, or sulcus, just below the acromion, made prominent by downward traction on the arm. Flattening of the rounded lateral aspect of the shoulder may indicate anterior dislocation of the GH joint or deltoid paralysis. Posterior dislocation of the GH joint is associated with flattening of the rounded anterior aspect of the shoulder.

Rupture of the long biceps tendon is associated with bunching up of the belly of the biceps muscle distally, made prominent by resisted elbow flexion and forearm supination (Popeye sign or Popeye deformity). In contrast, in a distal biceps tendon rupture, there is retraction of the muscle belly proximally. In thoracic scoliosis, one shoulder often appears lower than the other. Sprengel deformity is characterized by a congenitally small, high-riding scapula, sometimes associated with underdeveloped ipsilateral scapular muscles and webbing of the neck. Winging of the scapula, in which the medial border of the scapula moves away from the posterior chest wall, indicates injury to the long thoracic nerve with serratus anterior paralysis or other causes, such as clavicular malunion. Winging of the scapula is made more prominent by performance of a modified push-up against the wall with hands outstretched. Wasting of the supraspinatus muscle suggests a tear of the supraspinatus tendon or a suprascapular nerve lesion. Atrophy of the infraspinatus muscle can result from a tear of the infraspinatus tendon or a suprascapular nerve injury.

PALPATION

Palpation should begin with assessment of all four shoulder articulations (sternoclavicular, acromioclavicular, glenohumeral, and scapulothoracic) for warmth, tenderness, swelling, crepitus, or masses. This will help localize the site of a patient’s complaint and narrow the potential differential diagnosis.

Arthritis of the SC and AC joints is associated with local tenderness, synovial swelling, effusion, and sometimes crepitus on shoulder shrugging. Arthritis of the GH joint is characterized by global tenderness felt through the overlying deltoid in the anterior, lateral, and posterior subacromial areas.

Bicipital tenosynovitis is associated with localized tenderness over the tendon in the bicipital groove as the patient externally rotates the shoulder. The groove normally faces anteriorly when the shoulder is internally rotated 10°.

Scapulothoracic bursitis is associated with posterior subscapular pain and “grinding” or crepitus with scapulothoracic movements. In the so-called snapping scapula syndrome, protraction and retraction of the scapula is associated with audible and palpable grating, best felt at the superomedial corner of the scapula. This is caused by rubbing of the scapula over the underlying ribs.

RANGE OF MOTION

Range-of-motion testing should include both active and passive assessments of shoulder forward flexion, extension, abduction, adduction, internal rotation, and external rotation. Limitations in active range of motion when passive range is maintained points to a deficit in the motor unit for that movement. This may be a problem with the motor nerve, muscle, or tendon responsible for the motion. Loss of passive range of motion is commonly associated with degenerative disorders, such as arthritis, or adhesive capsulitis.

Shoulder abduction involves synchronous movements of the GH, SC, and AC joints and rotation of the scapula on the chest wall. The initial 30° of abduction, achieved by contraction of the supraspinatus, takes place at the GH joint with little movement of the scapula. Beyond 30°, an approximate 2:1 ratio exists between GH and scapular movements. The combined movement is referred to as the scapulohumeral rhythm. Normal shoulder abduction is 180° (Figure 2-4).

FIGURE 2-4 SHOULDER ABDUCTION: SIDEWAYS ARC, CORONAL PLANE.

To test forward flexion of the shoulder (deltoid, coracobrachialis, and biceps muscles; normal range 180°; Figure 2-5), the patient flexes the joint with the elbow extended, while the examiner stabilizes the scapula with one hand and resists forward flexion with the other hand placed over the upper arm. To test extension (latissimus dorsi, teres major, and deltoid muscles; normal range 60°; see Figure 2-5), the patient extends the shoulder, with the forearm fully pronated, while the examiner immobilizes the scapula and resists extension. With the shoulder abducted to 90° and the elbow flexed at 90°, the normal range of internal and external rotation is 90° each (Figure 2-6). With the elbow placed at the side at the waist, the normal range of external rotation is about 45° to 90°, and internal rotation is about 55° to 80° before its motion is stopped by the body; it may be as much as 120° if the patient can reach behind the back to touch the inferior angle of the opposite scapula (Apley scratch test). This is a functional movement required for daily activities, such as reaching a back pocket, scratching the back, or cleansing the perineum.

FIGURE 2-5 SHOULDER FORWARD FLEXION AND EXTENSION.

FIGURE 2-6 SHOULDER INTERNAL AND EXTERNAL ROTATION.

As the patient elevates the arm in abduction, the examiner can assess for the presence of a painful arc. Abduction to 45° to 60° is often painless. A painful arc between 60° and 120° is characteristic of subacromial impingement with rotator cuff tendinitis or subacromial bursitis. The pain often decreases beyond 120°, as the compression of the rotator cuff beneath the coracoacromial arch lessens. Pain between 120° and 180° may indicate abnormalities of the AC joint, whereas GH arthritis causes pain throughout the arc of abduction.

Reverse scapulohumeral rhythm, or greater scapulothoracic than GH movements during abduction, occurs in adhesive capsulitis; instead of the normal, smooth abduction, the patient appears to be “hitching” the entire shoulder complex upward. The capsular pattern of restricted shoulder movements typically observed in adhesive capsulitis is characterized by greater limitation of external rotation than of other movements. In GH arthritis, abduction and rotation are the earliest and most severely restricted movements.

SPECIAL TESTS

Special tests for the shoulder are plentiful. These tests are designed to elicit evidence of impingement, rotator cuff dysfunction, superior labral anterior and posterior (SLAP) lesions, irritation of the long head of the biceps, and shoulder instability. The sensitivity and specificity of each of these tests has been an area of much study. A recent meta-analysis on this topic reveals significant variability in the sensitivity and specificity of these tests, depending on the population studied and the pretest probability of the condition in the population being studied. A summary of these findings is presented in Table 2-2.

Tests for Shoulder Impingement

The Neer impingement sign is elicited with the patient seated and the examiner standing. Scapular rotation is prevented by one hand, as the other elevates the patient’s arm midway between abduction and flexion. In a positive test, the patient experiences pain in the overhead position near the end of shoulder elevation, as the greater tuberosity impinges against the acromion (Figure 2-7). The pain can be relieved by subacromial injection of 5–10 mL of 1.0% lidocaine (Neer impingement test).

FIGURE 2-7 NEER IMPINGEMENT TEST.

In the Hawkins impingement sign, the humerus is forward flexed to 90° and internally rotated, while the examiner’s other hand restricts scapular movements (Figure 2-8). This causes impingement of the greater tuberosity against the anterior acromion with reproduction of the patient’s symptoms. In patients with impingement and supraspinatus tendinitis or a tear, the Jobe test, supraspinatus isolation test, or empty can sign is positive: pain is elicited on resisted elevation of the arm to 90° midway between abduction and forward flexion, with the thumb pointing downward in internal rotation (Figure 2-9).

FIGURE 2-8 HAWKINS IMPINGEMENT SIGN.

FIGURE 2-9 SUPRASPINATUS TEST (EMPTY CAN SIGN).

In subcoracoid impingement, there is impingement of the rotator cuff between the lesser tuberosity and the lateral aspect of the coracoid process during abduction and internal rotation. It commonly occurs in the throwing athlete. This type of impingement is associated with anteromedial shoulder pain and a positive Gerber subcoracoid test: painful restriction of internal rotation when the shoulder is abducted or flexed 90°, because this position produces the narrowest coracohumeral distance. Combined forward flexion, internal rotation, and cross-arm adduction (coracoid impingement test) also causes pain. The coracoid impingement test differs from the O’Brien active compression test for superior labral tears, in which the patient actively resists the examiner while performing the maneuver. The pain of subcoracoid impingement can be relieved by a lidocaine injection between the humeral head and the coracoid process.

Tests of the Rotator Cuff

The supraspinatus (suprascapular nerve) is tested with the shoulder abducted 90°, flexed 30°, and internally rotated with the thumb pointing downward, while the examiner fixes the scapula with one hand and resists abduction with the other hand. This is known as the Jobe test, the supraspinatus isolation test, or the empty can sign (see Figure 2-9). In complete supraspinatus tears, the drop-arm test is positive: the patient is unable to actively maintain 90° of passive shoulder abduction or to slowly lower the arm to the side. With a partial supraspinatus tear, there is wasting and weakness of the supraspinatus muscle. The supraspinatus test, Neer impingement sign, and Hawkins impingement sign are often positive.

Infraspinatus and teres minor tears are associated with weakness of external rotation and a positive external rotation lag sign (ERLS): with the patient sitting, elbow 90° flexed, and the shoulder held by the examiner at 20° to 90° abduction and maximal external rotation, the patient is asked to actively maintain the position of external rotation as the examiner releases the wrist, and a “lag” or “angular drop” occurs. An alternative maneuver is the Hornblower Test. This test involves external rotation with the shoulder in 90° of abduction in the scapular plane. The elbow is flexed 90°, and the patient externally rotates against the resistance of the examiner’s hand (Figure 2-10). Weakness of external rotation in this position constitutes a positive test.

FIGURE 2-10 HORNBLOWER TEST.

This test involves external rotation with the shoulder in 90° of abduction in the scapular plane. The elbow is flexed 90°, and the patient externally rotates against the resistance of the examiner’s hand.

Subscapularis tears are associated with weakness of internal rotation and a positive subscapularis lift-off test: after maximal internal rotation of the shoulder with the dorsum of the hand held against the inferior aspect of scapula, the patient is unable to lift the hand off his back (Figure 2-11). A subscapularis tear is also detected by the belly press test (Figure 2-12). The patient presses the abdomen with the palm of the hand (internal rotation), and if the subscapularis is intact, the patient can maintain pressure without the elbow dropping backward; if there is a subscapularis tear, maximal internal rotation cannot be maintained, and the elbow drops back behind the trunk (positive belly press test). The patient exerts pressure on the abdomen by extending the shoulder rather than by internally rotating it. The test is particularly useful in those patients with restricted internal rotation who cannot place the hand behind the back to perform the lift-off test.

FIGURE 2-11 LIFT-OFF TEST.

FIGURE 2-12 BELLY PRESS TEST.

Tests for Labral Tears and Biceps Tendon Pathology

In bicipital tenosynovitis, pain in the bicipital groove is reproduced by resisted supination of the forearm with the elbow 90° flexed (Yergeson sign or supination sign; Figure 2-13) and by the more sensitive Speed test, in which there is pain on resisted flexion of the shoulder with the elbow extended and the forearm supinated.

FIGURE 2-13 YERGESON SIGN.

In the O’Brien active compression test, with the patient standing, elbow extended, and the shoulder forward flexed 90°, adducted 15°, and internally rotated, so that the thumb points downward, the examiner applies downward pressure on the proximal forearm against the patient’s resistance (Figure 2-14). The shoulder is then externally rotated, and the forearm is supinated, after which the maneuver is repeated. The test is positive if pain is elicited with the first maneuver but not with forearm supination. The thumb-down position (internal rotation) compresses the biceps–glenoid–labrum anchor, causing pain or a click deep in the shoulder if a SLAP lesion is present. In traumatic AC joint lesions, the O’Brien test may also produce more superficial pain on top of the shoulder.

FIGURE 2-14 THE O’BRIEN ACTIVE COMPRESSION TEST.

Kim et al. (2001) described the biceps load II test to assess for the presence of a SLAP lesion. In this test, the patient lies supine with the arm abducted 120°, the elbow flexed to 90°, and the forearm supinated. The patient then flexes the elbow against the resistance of the examiner. Pain elicited by this maneuver constitutes a positive test.

The crank test is also used to detect a SLAP lesion. In this test the arm is abducted 160° with the elbow flexed 90°. The examiner then applies a compressive load across the joint while performing rotation of the shoulder. Pain, usually with external rotation of the shoulder, constitutes a positive test (Figure 2-15).

FIGURE 2-15 THE CRANK TEST.

This test is also used to detect a SLAP lesion.

Tests for Glenohumeral Instability

With the patient supine, the shoulder is 90° abducted and 90° externally rotated; the examiner then applies forward pressure to the posterior aspect of the humeral head (Figure 2-16A). In the presence of GH instability and recurrent anterior subluxation, the patient suddenly becomes apprehensive and complains of pain in the shoulder (positive anterior apprehension test). The relocation test or containment sign (Figure 2-16B) is then performed by applying posterior pressure on the anterior aspect of the humeral head, to push the subluxed humeral head back in the glenoid fossa. Patients with GH instability and secondary impingement experience marked pain relief (positive relocation test). The examiner may then be able to externally rotate and extend the shoulder several degrees further while maintaining the posteriorly directed force on the humeral head. On release of the pressure on the humerus at this point, the patient complains of sudden pain (positive anterior release sign). The sign is more sensitive than the apprehension-relocation test in detecting occult GH instability.

FIGURE 2-16 A, Anterior apprehension test. B, Containment sign.

With the patient standing or sitting and the arm at the side, the examiner stabilizes the scapula with one hand while drawing the humeral head anteriorly or posteriorly with the other hand. GH instability is associated with anterior and posterior displacement (translation) of the humeral head on the fixed scapula (positive anterior and posterior drawer signs). Laxity of the shoulder capsule and ligaments results in inferior subluxation of the humerus on downward traction of the arm, which produces a depression or hollow between the lateral edge of the acromion and the humeral head (positive sulcus sign).

ASPIRATIONS AND INJECTIONS

Aspirations and injections are done about the shoulder for a number of indications. These include aspiration of a joint for synovial fluid analysis to aid in the diagnosis of inflammatory or septic arthritis. Injections of local anesthetic and antiinflammatory medications can be both diagnostic and therapeutic. Injection of a specific site, if accompanied by symptomatic relief, can help confirm the diagnosis and aid further treatment. When performing these injections, sterile technique should always be adhered to. An example of the required equipment is shown in Figure 2-17.

FIGURE 2-17 SOME REQUIRED EQUIPMENT FOR INJECTIONS AND ASPIRATIONS.

For subacromial bursa and rotator cuff tendinitis, with the patient sitting and the shoulder slightly externally rotated, the needle is inserted about 1 cm below the posterior border of the acromion and directed medially, anteriorly, and slightly superiorly toward the tip of the coracoid process to a depth of 2 to 3 cm into the subacromial bursa (posterior subacromial approach, Figure 2-18). A fluid-distended subacromial bursa can be aspirated and injected via a lateral approach (Figure 2-19).

FIGURE 2-18 INJECTION OF SUBACROMIAL BURSA AND ROTATOR CUFF TENDONS (POSTERIOR SUBACROMIAL APPROACH).

FIGURE 2-19 ASPIRATION AND INJECTION OF SUBACROMIAL BURSA (LATERAL APPROACH).

The GH joint is injected using a posterior approach. The entry point is two fingers’ breadth medial and inferior to the palpated posterolateral border of the acromion. The needle is directed anteromedial toward the coracoid process (Figure 2-20).

FIGURE 2-20 INJECTION OF THE GLENOHUMERAL JOINT.

For injection of the bicipital tendon sheath, the patient is sitting or supine, and the tendon is palpated in the bicipital groove while the shoulder is externally rotated. The point of maximum tenderness is marked, and the needle is inserted at an angle of 30° to 45° into the sheath. It is then directed superiorly along the tendon for about 2 cm before the sheath is aspirated and injected (Figure 2-21). Care is taken to avoid intratendinous steroid injection, which can lead to tendon rupture.

FIGURE 2-21 INJECTION OF THE LONG BICEPS TENDON SHEATH.

The AC and SC joints are injected with the patient sitting or standing with the arm at the side. The AC or SC joint is palpated, and the needle is inserted via a superior and anterior approach into the joint and directed inferiorly to a depth of about 0.5 cm. Care is taken not to inject directly into the intraarticular disk, because this can damage the disk and cause secondary osteoarthritis (Figure 2-22).

FIGURE 2-22 INJECTION OF THE ACROMIOCLAVICULAR JOINT.