Neck pain and pain that radiates below the elbow are often subtle signs of a cervical spine disorder that is mistaken for a shoulder problem. The patient should be asked about paresthesias and muscle weakness. Pneumonia, cardiac ischemia and peptic ulcer disease can present with shoulder pain.
A history of malignancy raises the possibility of metastatic disease. The patient should be asked about previous corticosteroid injections, particularly in the setting of osteopenia or rotator cuff tendon atrophy. A complete physical examination includes inspection and palpation, assessment of range of motion and strength, and provocative shoulder testing for possible impingement syndrome and glenohumeral instability. The neck and the elbow should also be examined to exclude the possibility that the shoulder pain is referred from a pathologic condition in either of these regions.
The physical examination includes observing the way the patient moves and carries the shoulder. The patient should be properly disrobed to permit complete inspection of both shoulders. Swelling, asymmetry, muscle atrophy, scars, ecchymosis and any venous distention should be noted.
Deformity, such as squaring of the shoulder that occurs with anterior dislocation, can immediately suggest a diagnosis. Atrophy of the supraspinatus or infraspinatus should prompt a further work-up for such conditions as rotator cuff tear, suprascapular nerve entrapment or neuropathy. Palpation should include examination of the acromioclavicular and sternoclavicular joints, the cervical spine and the biceps tendon.
The anterior glenohumeral joint, coracoid process, acromion and scapula should also be palpated for any tenderness and deformity. Because the complex series of articulations of the shoulder allows a wide range of motion, the affected extremity should be compared with the unaffected side to determine the patient's normal range.
Active and passive ranges should be assessed. For example, a patient with loss of active motion alone is more likely to have weakness of the affected muscles than joint disease. Shoulder abduction involves the glenohumeral joint and the scapulothoracic articulation.
Glenohumeral motion can be isolated by holding the patient's scapula with one hand while the patient abducts the arm.
The first 20 to 30 degrees of abduction should not require scapulothoracic motion. With the arm internally rotated palm down , abduction continues to degrees. Beyond degrees, full abduction is possible only when the humerus is externally rotated palm up. The Apley scratch test is another useful maneuver to assess shoulder range of motion Figure 2. In this test, abduction and external rotation are measured by having the patient reach behind the head and touch the superior aspect of the opposite scapula.
Conversely, internal rotation and adduction of the shoulder are tested by having the patient reach behind the back and touch the inferior aspect of the opposite scapula. External rotation should be measured with the patient's arms at the side and elbows flexed to 90 degrees. Apley scratch test. The patient attempts to touch the opposite scapula to test range of motion of the shoulder.
Left Testing abduction and external rotation. Right Testing adduction and internal rotation. In evaluating the rotator cuff, the patient's affected extremity should always be compared with the unaffected side to detect subtle differences in strength and motion. A key finding, particularly with rotator cuff problems, is pain accompanied by weakness.
True weakness should be distinguished from weakness that is due to pain. A patient with subacromial bursitis with a tear of the rotator cuff often has objective rotator cuff weakness caused by pain when the arm is positioned in the arc of impingement.
Conversely, the patient will have normal strength if the arm is not tested in abduction. The supraspinatus can be tested by having the patient abduct the shoulders to 90 degrees in forward flexion with the thumbs pointing downward.
The patient then attempts to elevate the arms against examiner resistance Figure 3. The patient attempts to elevate the arms against resistance while the elbows are extended, the arms are abducted and the thumbs are pointing downward. Next, with the patient's arms at the sides, the patient flexes both elbows to 90 degrees while the examiner provides resistance against external rotation Figure 4. This maneuver is used to evaluate the function of the infraspinatus and teres minor muscles, which are mainly responsible for external rotation.
The patient attempts to externally rotate the arms against resistance while the arms are at the sides and the elbows are flexed to 90 degrees.
Subscapularis function is assessed with the lift-off test. The patient rests the dorsum of the hand on the back in the lumbar area. Inability to move the hand off the back by further internal rotation of the arm suggests injury to the subscapularis muscle. A modified version of the lift-off test is useful in a patient who cannot place the hand behind the back. In this version, the patient places the hand of the affected arm on the abdomen and resists the examiner's attempts to externally rotate the arm.
Provocative tests provide a more focused evaluation for specific problems and are typically performed after the history and general examination have been completed Table 2. Neer's impingement sign is elicited when the patient's rotator cuff tendons are pinched under the coracoacromial arch.
The test 4 is performed by placing the arm in forced flexion with the arm fully pronated Figure 5. The scapula should be stabilized during the maneuver to prevent scapulothoracic motion. Pain with this maneuver is a sign of subacromial impingement. Neer's test for impingement of the rotator cuff tendons under the coracoacromial arch. The arm is fully pronated and placed in forced flexion. The Hawkins' test is another commonly performed assessment of impingement.
Pain with this maneuver suggests subacromial impingement or rotator cuff tendonitis. One study 6 found Hawkins' test more sensitive for impingement than Neer's test.
Hawkins' test for subacromial impingement or rotator cuff tendonitis. The arm is forward elevated to 90 degrees, then forcibly internally rotated. A possible rotator cuff tear can be evaluated with the drop-arm test. This test is performed by passively abducting the patient's shoulder, then observing as the patient slowly lowers the arm to the waist. Often, the arm will drop to the side if the patient has a rotator cuff tear or supraspinatus dysfunction.
The patient may be able to lower the arm slowly to 90 degrees because this is a function mostly of the deltoid muscle but will be unable to continue the maneuver as far as the waist. Patients with acromioclavicular joint dysfunction often have shoulder pain that is mistaken for impingement syndrome. The cross-arm test isolates the acromioclavicular joint. The patient raises the affected arm to 90 degrees. Active adduction of the arm forces the acromion into the distal end of the clavicle Figure 7.
Pain in the area of the acromioclavicular joint suggests a disorder in this region. Cross-arm test for acromioclavicular joint disorder.
The patient elevates the affected arm to 90 degrees, then actively adducts it. The tests described in this section are useful in evaluating for glenohumeral joint stability. Because the shoulder is normally the most unstable joint in the body, it can demonstrate significant glenohumeral translation motion. Again, the uninvolved extremity should be examined for comparison with the affected side. The anterior apprehension test is performed with the patient supine or seated and the shoulder in a neutral position at 90 degrees of abduction.
The examiner applies slight anterior pressure to the humerus too much force can dislocate the humerus and externally rotates the arm Figure 8. Pain or apprehension about the feeling of impending subluxation or dislocation indicates anterior glenohumeral instability. Apprehension test for anterior instability.
The patient's arm is abducted to 90 degrees while the examiner externally rotates the arm and applies anterior pressure to the humerus. The relocation test is performed immediately after a positive result on the anterior apprehension test.
With the patient supine, the examiner applies posterior force on the proximal humerus while externally rotating the patient's arm. These form an arch above the rotator cuff and humeral head. The long head of biceps passes over the humeral head curving in two planes forming the shape of a question mark. It is recognised as providing a small degree of stability to the gleno-humeral joint.
JBJSB, ]. The biceps pulley is a stabiliser of the long head of biceps in the biceps groove. Rupture of this pulley with a rotator cuff tear leads to medial subluxation of the long head of biceps and dysfunction.
The fusing of the rotatorcuff tendons suggests that they act more as a combined and integrative structure than as single entities. The microstructure of the rotator cuff tendons near the insertions of the supraspinatus and infraspinatus has been further described as a five-layer structure:.
The fibre orientation also differs along the length of the rotator cuff tendon. Near the musculotendinous junctions, the tendons are composed mainly of parallel homogeneous collagen fibers but become flat ribbonlike bundles of fibers that cross at an angle of about 45 degrees as they reach insertion into the humerus [Gohlke et al.
Because of the various fiber orientations and distinct layers within the superiorcapsular complex, significant shear forces likely exist and may have a role in cuff tears. These intratendinous variations in the cuff structure may explain why intrasubstance tears occur. Shear forces are probably directed to layer four, which is the site of development of intratendonous cuff tears. These tend to be degenerate tears of the cuff. The midsubstance of the supraspinatustendon is primarily composed of Type I collagen, with relatively small amounts of Type III collagen, decorin, and biglycan.
The fibrocartilage portion of the insertion has a collagen and proteoglycan content similar to that of tissues that have been subjected to compressive loads. This is partly due to the wrapping of thetendon around the humerus. Therefore, it mainly contains Type II collagen and larger proteoglycans such as aggrecan.
The histological organization, however, does not resemble mature fibrocartilage. In rotator cuff tendinopathy, an increase in collagen Type III, a protein that plays a role in healing and repair, and glycosaminoglycan and proteoglycan content has been observed. These compositional changes may be adaptive, pathologic, or both, and are found to be altered in the older population. Furthermore, recent studies have shown increased levels of smooth muscle actin SMA in torn rotator cuffs.
SMA-positive cells have been shown to contract a collagen-glycosaminoglycan analog in vitro. SMA-containing cells in rotator cuff tears may react with the high levels of GAG and proteoglycan resulting in retraction of the ruptured rotator cuff and inhibition of potential healing. The major arterial supply to the rotator cuff is derived from the ascending branch of the anterior humeral circumflex artery, the acromial branch of the thoracoacromial artery, as well as the suprascapular and posterior humeral circumflex arteries.
The pathogenesis of rotator cuff tears has been considered to be influenced by the microvascular supply of the rotator cuff tendons. Most cadaver studies have demonstrated a hypovascular area within the critical zone of the supraspinatustendon. It has been suggested that this area of hypovascularity has a significant role in the attritional degeneration of the aging tendon. More recent studies of the microvascular supply to the supraspinatus tendon in symptomatic patients with impingement syndrome suggest that in the area of greatest impingement, i.
In vivo analysis using orthagonal polarisation spectral imaging has demonstrated that there is good vascularity of supraspinatus, even in the critical zone in intact rotator cuffs [ Biberthaler et al.
A - capillaries within normal supraspinatus tendon. B - absent capillaries in the edges of a supraspinatus cuff tear. We will explore some of the biomechanical reasons for the development of cuff tears, rather than the differences between extrinsic and intrinsic causes. Using finite element modelling of the rotator cuff the stress concentrations were studies in varying degrees of subacromial impingement. The stress concentrations were highest in the critical zone of the cuff with tears potentiating on the articular side, bursal side and intratendinous.
Articular side tears were slightly more common [ Mehta et al. Neer originally believed that rotator cuff tears arose fom a mechanical process secondary to progressive wear. The morphology of the anterior acromion has been found to correlate with cuff tears. This has also been borne out by recent clinical studies where acromial morphology was found to be a predictor for cuff tears [ Gill et al. JSES, ]. Bigliani classification of acromial morphology. Type 3 was more commonly associated with rotator cuff tears [ Bigliani, Clin Sports Med, ].
The triad of anterior capsular laxity, posterior contraction and internal impingement was originally described in overhead athletes [ Walch et al. The posterior condensation gives rise to all intrinsic shoulder muscles, including the teres minor. The muscle groups are well-established by 8 weeks. The teres minor is supplied by the subscapular artery and one of its branches, the circumflex scapular artery, as well as the posterior circumflex humeral artery.
The subscapular artery and the posterior circumflex humeral artery arise from the third, most distal portion of the axillary artery. The subscapular artery is the largest branch off of the axillary artery. It travels caudally before dividing into 2 arteries: the circumflex scapular and the thoracodorsal. The circumflex scapular artery travels around the lateral border of the scapula between the subscapularis and teres minor.
It moves cranially through the triangular space, created by the teres minor superiorly, teres major inferiorly, and long head of the triceps brachii laterally, into the infraspinatus fossa where it joins the scapular anastomosis. Along its route, the circumflex scapular artery supplies the teres minor. The posterior humeral circumflex artery is a more distal branch off of the third portion of the axillary artery.
It travels posteriorly with the axillary nerve through the quadrangular space, bounded by the teres minor superiorly, teres major inferiorly, the surgical neck of humerus laterally, and long head of triceps brachii medially. Then the artery moves anteriorly around the surgical neck of the humerus to supply the shoulder joint. Along its route, the posterior humeral circumflex artery supplies the teres minor. The axillary nerve innervates the teres minor.
The axillary nerve, composed of nerve roots C5 and C6, arises from the posterior cord of the brachial plexus. First, the axillary nerve is posterior to the axillary artery and anterior to the subscapularis muscle, then it travels to the inferior edge of the subscapularis muscle. Here, it moves posteriorly out of the axilla with the posterior circumflex humeral artery PCHA through the quadrangular space, created by the teres minor superiorly, teres major inferiorly, the surgical neck of humerus laterally, and long head of triceps brachii medially.
When it enters the posterior scapula, the axillary nerve bifurcates into two terminal branches; the posterior terminal branch innervates the teres minor. The rotator cuff comprises 4 muscles: supraspinatus, infraspinatus, teres minor, and subscapularis. The supraspinatus, infraspinatus, and teres minor all arise from the posterior scapula and insert on the greater tubercle of the humerus. The subscapularis arises from the subscapular fossa of the anterior scapula and inserts on the lesser tubercle of the humerus.
Collectively, the rotator cuff stabilizes the glenohumeral joint, which is a far more shallow and unstable ball-and-socket joint than the hip. Each muscle also helps with certain movements of the arm. The supraspinatus is responsible for the first 15 degrees of abduction; the deltoid, an intrinsic muscle of the shoulder that is not a rotator cuff muscle, is responsible for abduction from 15 to 90 degrees. The infraspinatus and teres minor both aid in lateral, or external, rotation of the arm at the shoulder.
The subscapularis, along with the teres major, another intrinsic muscle that is not part of the rotator cuff, and extrinsic muscles like the pectoralis major and latissimus dorsi, is responsible for medial, or internal, rotation of the arm. A rotator cuff tear, including a tear to the teres minor, will not heal without surgery; however, good function of the affected shoulder can often be gained non-surgically.
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