Acute Injuries of the Shoulder Complex and Arm




Anatomy



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The anatomy of the shoulder (Figures 20-1 and 20-2) is complex because of the unconstrained nature of the joint, which allows an arc of motion greater than any other joint in the body. The shoulder is stabilized by both bony and soft tissue restraints (Table 20-1). The glenoid forms a small cup, which minimally constrains and stabilizes the humeral head (Figure 20-3). The glenoid labrum, a fibrocartilage lip, adds to the depth and width of the glenoid and is commonly injured in shoulder dislocations and in biceps tendon attachment injuries. The superior, middle, and inferior glenohumeral ligaments stabilize the shoulder through different arcs of motion, and are commonly injured along with the labrum in both adult and younger athletes.1





Figure 20-1



Anatomy of shoulder. (Used with permission from Van De Graaff KM. Human Anatomy. 6th ed. New York:McGraw Hill;2002:Figure 8-25, p 216.)






Figure 20-2



Anatomy of shoulder. (Used with permission from Van De Graaff KM. Human Anatomy. 6th ed. New York:McGraw Hill;2002:Figure 8-25, p 216.)






Table 20-1. Glenohumeral Stabilizers





Figure 20-3



Anatomy of shoulder. (Used with permission from Van De, Graff KM. Human Anatomy, 6th ed. New York:McGraw Hill;2002:Figure 8-25, p 216.)





The rotator cuff (Figures 20-4 and 20-5) provides secondary and dynamic stability to the shoulder, as do the periscapular muscles, which aid in stabilizing the shoulder and position it in space. There is some debate as to whether the biceps and its long head provide significant dynamic shoulder stability or not, but the biceps tendon and associated muscles are commonly injured in association with other patterns of shoulder injury. Although significant portion of shoulder motion is caused by the motion of the shoulder girdle itself, the scapula, the acromioclavicular (AC) joint, clavicle and the sternoclavicular (SC) joint, all contribute to the scapulothoracic and shoulder motion, and this needs to be addressed in detail when considering shoulder injuries. Basic movements of the shoulder are depicted and described in Figure 20-6.





Figure 20-4



Rotator cuff muscles (anterior view).






Figure 20-5



Rotator cuff muscles (posterior view).






Figure 20-6









Movements of shoulder. (A) Flexion (B). Extension (C). Adduction. (D). Abduction (E). Internal rotation (F). External rotation (G). External rotation (right) and internal rotation (left) at 90 degree abduction of shoulder.





Definitions and Epidemiology



Injuries resulting from acute macrotrauma to the shoulder, scapulothoarcic region and proximal arm in the young athlete are listed in Table 20-2. Although sport-related acute injuries to the shoulder and arm are most common in contact—collision sports, such injuries also occur in noncontact throwing sports and weight lifting and similar activities.




Table 20-2. Major Acute Injuries Around the Shoulder and Proximal Arm




Mechanisms



The mechanisms of shoulder injuries are reviewed with specific injuries below.




Clinical Presentation



The history should ascertain the mechanism of injury. The athlete with acute shoulder area injury will present with localized pain that is exacerbated by movements. There will be localized tenderness and characteristic deformity depending upon the nature of the injury. Because of the pain, the movements are restricted. The shoulder area is examined based on the methods described under the “Physical Examination” section below. Abnormal findings are further described under specific injuries.




Physical Examination



Always examine the neck and cervical spine in a patient with shoulder and arm symptoms. Neurovascular examination of the entire upper limb should be an integral part of assessing shoulder complex and arm symptoms.



Inspection



Observe the patient from front, back, and side and systematically note abnormal findings including sternoclavicular joint, the clavicle, acromioclavicular joint, the shoulder, and the scapulothoracic area. Note any swelling, skin break, apparent deformity, asymmetry compared with the uninjured side, and muscle atrophy. A step-off at AC Joint is seen in severe AC joint disruption. Note scapular winging at rest and on performing wall push-up.



Palpation



Palpate all areas systematically for tenderness and crepitus.



Movements



Assess active and passive shoulder and scapulothoracic movements. Observe the quality and form of the movements from front, side, and behind. Note the scapulothoracic motion. Assess strength by testing movements against manual resistance.



Special Tests are described and depicted in Figures 20-7, 20-8, 20-9, 20-10, 20-11, 20-12, 20-13, 20-14, 20-15, 20-16, 20-17, 20-18, 20-19, 20-20, and 20-21.




Figure 20-7



Neer sign. Sudden and forceful forward flexion of the arm impinges the greater tuberosity against the inferior surface of the acromion. Elicitation of pain is considered a positive Neer impingement sign.





Figure 20-8



Hawkins-Kennedy sign. With the athlete standing or sitting on the examination table the arm is forward flexed to 90 degree and forcibly rotated internally. Pain is elicited in injury of the supraspinatus tendon as it impinges against the anterior surface of the coracoacromion ligament and coracoid process.





Figure 20-9



Supraspinatus test. With the athlete standing or sitting on the examination table the shoulder is abducted to 90 degree, internally rotated (thumbs down) and moved forward to approximately 30 degree. Downward manual resistance is applied while the athlete attempts to hold this position. Pain or weakness is indicative of supraspinatus strain. The test may also be positive in case of suprascapular neuropathy.





Figure 20-10




Drop arm test. The examiner assists the athlete to bring the shoulder to a position of 90-degree abduction (A). Then the athlete is asked to slowly lower the arm to the side (B). In case of rotator cuff tear, pain is elicited as the athlete is lowering the arm or the arm drops suddenly to the side because of weakness.





Figure 20-11



Speed test. With the arm straight and supinated the athlete is asked to forward flex against manual resistance. Pain and tenderness in the bicipital groove is indicative of biceps brachii tendinitis.





Figure 20-12




Yergason test. With the arm by the side, the elbow held at 90 degree, and forearm pronated (A), the athlete is asked to supinate the forearm and flex the elbow against manual resistance, while the examiner is palpating the biceps tendon over the bicipital groove with his other hand (B). Pain and tenderness is elicited in case of biceps tendnitis. Biceps tendon may also be felt to subluxate from the bicipital groove.





Figure 20-13



Apprehension test. With arm abducted at 90 degrees, the shoulder is gently rotated externally. In case of anterior glenohumeral instability the athlete feels a sense of apprehension as if the shoulder is going to dislocate.





Figure 20-14



Jobe relocation test. With the athlete supine and shoulder at the edge of the table the arm is abducted and shoulder gently rotated externally. In case of anterior instability the athlete will feel pain (or a sense of apprehension) during external rotation. At this point a posteriorly directed stress is applied to proximal arm with relief of the pain or apprehension.





Figure 20-15



Load and shift test. With the athlete seated resting arms by the side and palms resting on her thighs (thumbs posterior) the examiner from behind the athlete stabilizes the shoulder with one hand and grasps the head of the humerus with her other hand. The examiner then gently moves the head of the humerus in anterior direction and notes the amount of translation. A relative increase in the movement of the head of the humerus is associated with anterior instability.





Figure 20-16



Sulcus sign. With the athlete seated or standing with the arm by hers side and relaxed, the examiner grasps hers arm and pulls it downward. Appearance of a sulcus below the acromion is indicative of inferior shoulder instability.





Figure 20-17




O’Brien sign. The athlete’s shoulder is held in 90 degree of forward flexion, 10 degree of horizontal adduction, and full internal rotation. The examiner applies downward manual resistance to distal forearm while the athlete attempts to hold the position. Pain is elicited in case of glenoid labral tears.





Figure 20-18



Crank test. The athlete’s shoulder is held at 90-degree abduction, and then axial load is applied as the arm is internally rotated. In case of a SLAP lesion the athlete will feel pain or grinding sensation in the shoulder.





Figure 20-19



Anterior slide test. The athlete is sitting resting her hands on the waist. From behind the athlete, the examiner stabilizes the shoulder with one hand and with the other hand over the elbow applies anteroposterior force. In case of a tear of the glenoid labrum a pop or crack is felt as the head of the humerus slides over the labrum.





Figure 20-20



Cross adduction test. The athlete’s arm is held at 90 degree of abduction and then adducted across the chest. Pain is elicited at the acromioclavicular joint area in case of localized pathology.





Figure 20-21




Scapular retraction test. From behind the athlete the examiner stabilizes the medial border of the scapula as the athlete elevates the arm. A positive test is indicated by relief of rotator cuff impingement pain and suggests a role of the periscapular muscles in the pathophysiology and rehabilitation of the impingement syndrome.





Diagnostic Imaging



Plain films of the shoulder are indicated to assess the presence and nature of fractures and dislocations. Specific views may be needed for certain injuries as discussed in the subsequent sections. For assessment of soft tissue injuries such as musculotendinous tears, MRI is the study of choice. MR arthrogram may be indicated in the assessment of glenoid labral tears.2,3 Radiographic findings for specific injuries are described under individual conditions.




Treatment



Immediate treatment depends upon the nature of the injury. In general, in case of fracture with or without neurovascular involvement, the shoulder and arm should be splinted and immobilized in a sling and the athlete should be sent to the emergency department for definitive evaluation and orthopedic consultation as appropriate. Indications for orthopedic consultation are listed in Box 20-1.




Box 20-1 When to Refer.




Acute Glenohumeral Dislocation



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Definitions and Epidemiology



In a shoulder dislocation the humeral head is at some point completely translated outside the glenoid, and will usually require a reduction to replace the head into the glenoid. Anterior dislocations, in which the humerus is usually dislocated anterior and inferior to the glenoid, are by far the most common.



Shoulder dislocations in general are rare in children. In the athletic setting shoulder dislocations occur in adolescents most often near the time of skeletal maturity, mostly in collision sports. Up to 40% of all primary shoulder dislocations occur in patients younger than 22 years of age, and the overall incidence of shoulder dislocation is as high as 7% in youth hockey.1,4




Mechanism



The mechanism for anterior dislocations is an anteriorly directed force placed on an abducted and externally rotated shoulder, as in being blocked while attempting a throw or similar mechanism. Anterior dislocation can also result from a fall on the externally rotated abducted outstretched arm.




Clinical Presentation



With the more common anterior dislocation the athlete will present acutely on the field or on the sideline with pain, a prominent humeral head anteriorly, with the arm in external rotation, and will not want to move the shoulder. Palpate brachial artery. Test sensation to touch and pin prick over the arm. Loss of sensation over the lateral aspect of the shoulder over the deltoid indicates axillary nerve injury.

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Jan 21, 2019 | Posted by in SPORT MEDICINE | Comments Off on Acute Injuries of the Shoulder Complex and Arm
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